Abiotic and biotic factors influencing western United States coniferous forests - Bradley M. Lalande; Stromberger, Mary; Tinkham, Wade; Trivedi, Pankaj; Stewart, Jane (Digital Collections of Colorado (Colorado State University), 2019)
In the next decade, climate models suggest that global temperatures will continue to rise. In the western United States, increases in temperatures and changes in precipitation patterns will escalate the risk of drought conditions. These potentially warmer, drier conditions could induce physiological changes within trees, subsequently increasing stress on coniferous forests that are adapted to cool, wet environments. The abiotic stress accompanied by drought conditions can predispose susceptible hosts to biotic stress of insect and disease populations. In particular, high elevation subalpine fir (Abies lasiocarpa) have encountered higher than average mortality rates throughout the western United States in association with abiotic and biotic agents. Chapter 2 of this thesis investigated the potential drivers of subalpine fir mortality and determined how climatic factors and site and stand characteristics influenced the presence of mortality and biotic agents. The objectives were to identify factors driving subalpine fir mortality in Colorado and included 1) determine abiotic and biotic factors that directly and indirectly affect subalpine fir mortality, 2) determine factors associated with the presence of D. confusus or Armillaria spp., and 3) determine if climate variables were correlated to subalpine fir mortality or the presence of D. confusus and Armillaria spp. I hypothesized that sites with a higher density (i.e. basal area, trees per hectare, or canopy closure) would experience greater mortality due to decreased growth rates from competition and that D. confusus or Armillaria spp. prevalence would be a function of tree stress (i.e. increased density), elevation, slope, and departures from normal precipitation (i.e. drought), and minimum and maximum temperatures. Stand health monitoring plots found that the most relevant factors to subalpine fir mortality are the presence of D. confusus (p = 0.003) and the percent subalpine fir on plot (p = <0.0001). I identified that stand density (p = 0.0038), elevation (p = 0.0581), and Armillaria spp. (p = 0.0006) were the greatest influences on the presence of D. confusus, while the largest influences on the presence of Armillaria spp. are warmer maximum summer temperatures (p = 0.0136) and the presence of D. confusus (p = 0.0289). Results indicated that increased subalpine fir mortality was attributed to high stand density as a predisposing factor, warming temperatures as an inciting factor, and bark beetles (Dryocoetes confusus) and root disease (Armillaria spp.) as contributing factors. The combination of predisposing, inciting, and contributing factors suggests that subalpine mortality can be defined as subalpine fir decline. Management strategies used to reduce the impact of subalpine fir decline will need to address ways to improve stand health, while decreasing populations of both, D. confusus and Armillaria spp. In regards to Armillaria, the inability to successfully manage the disease using current techniques highlights the need to find novel management strategies to minimize its impacts. Since this disease is a root pathogen, soil microbes likely influence its growth and survival. Utilizing soil microbial communities as biocontrols may assist in management of Armillaria. Field sampling within the Priest River Experimental Forest in northern Idaho provided the opportunity to observe how soil microbial communities are associated with two species of Armillaria, A. solidipes (primary pathogen) and A. altimontana (weak pathogen). My research objective for Chapter 3 was to identify the soil fungal communities associated with tree health status (healthy, moderate and dead) and each Armillaria species, A. solidipes and A. altimontana, both of which have differing ecological behaviors (virulent pathogen and non-pathogen, respectively) on western white pine. I hypothesized that soil microbial communities associated with virulent A. solidipes and non-pathogenic A. altimontana would differ in fungal richness and diversity with the latter having a greater richness and diversity due to its beneficial qualities to tree health. While richness and diversity is likely to shift among tree health with a greater diversity and richness for soils associated with healthy trees due to root exudate production near the rhizosphere. Soil samples were collected alongside western white pine (Pinus monticola), while Armillaria rhizomorphs were excavated near the roots. The most abundant fungal taxon was Mortierella spp., which functions as saprophyte decomposing dead and down wood. No significant differences in fungal diversity or richness were found in soils associated with Armillaria species, but, although not significant, there where slight differences between soils associated with moderate and dead trees with a greater diversity and richness in soils with dead trees (p = 0.18). Additionally, soil pH was significantly influenced by soil carbon, nitrogen, and organic matter, while moisture significantly influenced soil carbon, nitrogen, and organic matter, acting as indicators to overall health in the stand. Although not significantly different, more Hypocreaceae (Trichoderma), a known biocontrol for root pathogens, were found within soils associated with A. altimontana and healthy trees. More research is needed to solidify differences, yet these factors give insight into potential beneficial aspects of soil fungal communities in association with Armillaria species and tree health. Changing climates regimes outside of 30-year averages cause increased stress to forests. This stress may predispose trees to a greater abundance biotic agents such as bark beetles and secondary pathogens, such as Armillaria root disease specifically in association with subalpine fir in Colorado. Understanding the role that soil fungal communities play in association to Armillaria root disease and tree health may assist in forest management practices to increase the health of high elevation forests.

Seasonal Progression of Algal Development and Quality in Streams that Vary in Timing of Springtime Peak Flow - Angela Wright; J. A. Balik; B. W. Taylor (2019)
Climate driven shifts in stream hydrology from early, rapid snowmelt may have implications for algae growing within high altitude montane streams. Peak flow scours the benthic layer and clears senesced algal growth and sediment, effectively priming the substrate for new algal growth following peak flow. An earlier peak flow allows for a longer season for algae to accrue biomass, but the implications for algal resource quality are unknown. Algae are crucial components of aquatic ecosystems because they are the basal food resource for animals, and algal nutrient uptake can dominate stream nutrient cycling. This study considers how variation in the timing of peak streamflow of different streams in the southern Rocky Mountains could impact the resource quality and development of algae. Algal samples from these streams were analyzed for biomass, chlorophyll-a, community composition, and percent phosphorous. Baetis bicaudatus, a grazing mayfly, was also sampled as they can selectively feed on nutrient dense algae and therefore their developmental stage and body chemistry may characterize among stream variation in algal resource quality more effectively than bulk algal samples. I hypothesized that with shorter and earlier peak flows, algae will (1) accrue more biomass, (2) have higher amounts of chlorophyll, and (3) have poorer elemental resource quality than algae in a stream with a later peak flow. These hypotheses were tested along seven streams in the southwestern part of Colorado, USA. Analysis of variance (ANOVA) was used to see if there were differences in each variable among streams and dates. Biomass, phosphorus content, chlorophyll-A, and cell counts of algal phyla differed among streams, but only cell counts differed amongst dates. Although concrete conclusions about the effects of peak flow cannot be evaluated until streams have all been sampled to base flow this autumn, the differences detected among streams thus far suggest that an unknown factor is influencing algal development, and patterns in biomass and chlorophyll accrual are consistent with predictions based on these rivers’ melt order.

From Grain to Floodplain: Evaluating heterogeneity of floodplain hydrostatigraphy using sedimentology, geophysics, and remote sensing. - Nicholas Sutfin; H. F. Malenda; Sophie Stauffer; K. Singha; G. Guryan; J. C. Rowland; Kenneth Hurst Williams (Earth Surface Processes and Landforms, 2019)
AbstractStratigraphy is a fundamental component of floodplain heterogeneity and hydraulic conductivity and connectivity of alluvial aquifers, which affect hydrologic processes such as groundwater flow and hyporheic exchange. Watershed‐scale hydrological models commonly simplify the sedimentology and stratigraphy of floodplains, neglecting natural floodplain heterogeneity and anisotropy. This study, conducted in the upper reach of the East River in the East River Basin, Colorado, USA, combines point‐, meander‐, and floodplain‐scale data to determine key features of alluvial aquifers important for estimating hydrologic processes. We compare stratigraphy of two meanders with disparate geometries to explore floodplain heterogeneity and connectivity controls on flow and transport. Meander shape, orientation, and internal stratigraphy affected residence time estimates of laterally exchanged hyporheic water. Although the two meanders share a sediment source, vegetation, and climate, their divergent river migration histories resulted in contrasting meander hydrofacies. In turn, the extent and orientation of these elements controlled the effective hydraulic conductivity and, ultimately, estimates of groundwater transport and hyporheic residence times. Additionally, the meanders’ orientation relative to the valley gradient impacted the hydraulic gradient across the meanders—a key control of groundwater velocity. Lastly, we combine our field data with remotely sensed data and introduce a potential approach to estimate key hydrostratigraphic packages across floodplains. Prospective applications include contaminant transport studies, hyporheic models, and watershed models. © 2019 John Wiley & Sons, Ltd.

Análisis geomorfológico y paleoambiental de la depresión tectónica de Ullum-Zonda, Provincia de San Juan - Pablo Blanc (Conicet, 2019)
El objetivo de la presente tesis doctoral es evaluar la evolución geomorfológica del valle de Ullum-Zonda y las condiciones paleoambientales que prevalecieron en esta depresión durante el Cuaternario tardío. Para ello, se efectuó un análisis geomorfológico, morfotectónico y neotectónico de este valle y de dos grandes cuencas fluviales asociadas que forman parte de la misma depresión tectónica: las cuencas de los ríos de La Travesía y La Ciénaga. Se realizó, además, un análisis litofacial y geocronológico en diversos afloramientos de la Formación Valentín, con el fin de determinar el ambiente sedimentario en que se formó esta unidad. El valle de Ullum-Zonda, situado en la Precordillera de los Andes Centrales de Argentina es una depresión tectónica ubicada en el sector centro-sur de la Provincia de San Juan, en la República Argentina, a unos 20 km al oeste de la ciudad capital de San Juan. Constituye una depresión intermontana de fondo plano, elongada en sentido norte-sur con una extensión de aproximadamente 30 km y un ancho máximo de 14 km en su sector central. Abarca un área aproximada de 290 km2 y se halla a una altura promedio de 800 m s.n.m. Esta depresión forma parte del corredor tectónico Matagusanos-Maradona-Acequión (Perucca, 1990) en el cual convergen y colisionan dos fajas plegadas y corridas (FPC) con diferentes niveles de despegue (decôllement) y de vergencia opuesta: la faja plegada y corrida de piel fina y vergencia oriental de Precordillera Central y la faja plegada y corrida de piel gruesa y vergencia occidental de Precordillera Oriental. La interacción entre la dinámica fluvial del río San Juan, la deformación tectónica, y el clima local ha dado origen durante el Cuaternario a espesas secuencias sedimentarias que constituyen el relleno de esta depresión con espesores que superan los 1.200 m en algunos sectores. Parte de este relleno sedimentario está conformado por material fino (arenas, limos y arcillas) y ha sido interpretado por diversos autores como formado a partir de eventos “lacustres-palustres” que abarcaron en forma parcial y/o total la superficie del valle. Desde el punto de vista geomorfológico, el relieve del área de estudio se agrupó en tres grandes unidades morfoestructurales: la unidad montañosa, formada por el relieve montañoso y el relieve de lomadas; la unidad de transición, que abarca las geoformas de piedemonte y la unidad deprimida llamada también ambiente planizado, que se corresponde con las depresiones intermontanas por las que suele fluir un río y con presencia de pampas y barreales. Los cordones montañosos y unidades de lomadas ubicados al este del área de estudio, en el ámbito de Precordillera Oriental son, de sur a norte la sierras Chica de Zonda, Marquesado, Loma de Las Tapias, Loma de Ullum y sierra de Villicum. La Precordillera Central está representada de sur a norte por el cordón de Las Osamentas, cordón del Espinacito, Sierra Alta de Zonda, cerro Zonda, los cerros del complejo andesítico-dacítico de Ullum, la sierra de La Dehesa y las Lomitas de Matagusanos. Las lomadas compuestas por rocas de granulometría fina (limos y arcillas) no consolidadas o con débil cementación, poseen un aspecto típico de tierras malas o relieve de huayquerías (badlands), es decir laderas con incisión densa y profunda. Los piedemontes están caracterizados por geoformas de acumulación como abanicos aluviales, abanicos coluviales y conos de derrubios, y formas de erosión como glacis, pedimentos y terrazas fluviales. Los glacis presentan una capa aluvial de espesor variable y suelen estar afectados por deformación tectónica cuaternaria. En ciertos sectores, como en la Loma de Las Tapias y piedemonte oriental de la Sierra Chica de Zonda, algunos glacis se presentan profundamente incididos y es frecuente la presencia de relieve de badlands. La litología predominante en los depósitos cuaternarios es muy variada, textural y composicionalmente, dependiendo del área de procedencia y de la geología del macizo alimentador. La unidad deprimida está representada por las planicies aluviales de los ríos de La Travesía y de La Ciénaga y los mega-abanicos aluviales del río San Juan en el valle de Ullum-Zonda y Tulum. Se incluyen también en esta unidad los barreales de Matagusanos y Barrancas. En la cima de la Sierra Chica de Zonda, se reconocieron pequeñas depresiones de fondo plano con relleno de materiales finos, posiblemente originadas a partir de procesos kársticos. Estas depresiones presentan formas circulares a elongadas, en algunos casos en forma perpendicular al eje de la sierra controladas por lineamientos estructurales. Dado que el desarrollo de las dolinas de disolución requiere precipitaciones relativamente importantes, se infiere que las mismas se habrían formado durante un periodo un poco más húmedo y frío que el actual, aunque anterior al Último Máximo Glacial. En la cima y ladera oriental del cerro Zonda, por su parte, se reconocieron fallas normales, presumiblemente activas durante el Cuaternario tardío, que podrían responder a grandes estructuras de deformación gravitacional conocidas como sackungen. Este tipo de fenómeno implica la reptación ladera abajo de grandes bloques del macizo montañoso limitados por fallas relativamente profundas. La erosión fluvial y la orientación favorable de los estratos, controlada por un pliegue por propagación de falla con vergencia oriental, produjo laderas muy escarpadas en el flanco oriental de la sierra, lo que favorecería este tipo de procesos. La ausencia de evidencia de grandes depósitos de remoción en masa al pie de la sierra, sugiere que estas deformaciones se habrían producido en forma lenta y gradual (reptación de laderas) sin llegar a un colapso catastrófico. El análisis de la actividad tectónica relativa de frentes montañosos indicó que las sierras de Villicum (en su sector sur), Marquesado, Chica de Zonda y cordón de Las Osamentas se corresponden con la clase 2 (frentes con alta tasa relativa de actividad tectónica). La sierra de La Dehesa presenta características compartidas entre los frentes clase 2 y clase 3 indicando una tasa de actividad moderada a alta. En la sierra de La Dehesa, la deformación más reciente habría migrado hacia el este y se concentraría en la traza más oriental de la falla Talacasto-La Dehesa que discurre por el piedemonte de la sierra alejada del frente montañoso. En el cordón de Las Osamentas, el elevado grado de meteorización de las lutitas y areniscas devónicas favorecen los procesos erosivos, generando valles anchos en forma de U y numerosos procesos de remoción en masa en su ladera oriental, pudiendo llevar a una subestimación del grado de actividad tectónica relativa. Dicho frente presenta una morfología considerablemente rectilínea salvo por la presencia de valles prominentemente anchos. En el segmento central y norte de la sierra de Villicum, por su parte, la morfología del frente montañoso presenta un fuerte control litológico-estructural que dificulta la aplicación del método. En la quebrada de Zonda se reconocieron al menos tres niveles de terraza por sobre la llanura de inundación abandonada. La incisión y degradación observada en la superficie erosiva basal de algunas terrazas y el espesor muy variable de la cubierta aluvial que las recubre sugiere la ocurrencia de uno o varios ciclos de incisión-planización-agradación-incisión. A partir del análisis de modelos digitales de elevación de alta resolución, se detectó en el flanco oriental de las sierras de Marquesado y extremo norte de la Sierra Chica de Zonda, lo que aparenta ser un bloque sobre-elevado que abarca de oeste a este, desde la falla Villicum-Zonda hasta las localidades de Marquesado y La Bebida. La orientación del aparente límite oriental del bloque es coincidente con la orientación de las escamas tectónicas que conforman el extremo norte de la Sierra Chica de Zonda, por lo que esta anomalía podría representar la manifestación superficial del levantamiento de la sierra durante el Cuaternario, deformando la superficie del mega-abanico aluvial del río San Juan. La falta de evidencia de niveles aterrazados en el valle de Ullum-Zonda, equivalentes a los de la quebrada de Zonda y valle de Tulum (excepto aquellos adosados al piedemonte occidental de la sierra de Marquesado) sugiere que en gran medida la formación de las terrazas reconocidas, respondería principalmente a movimientos tectónicos en el bloque serrano oriental de la depresión, más específicamente al levantamiento del bloque Marquesado-Chica de Zonda. El factor climático por su parte habría constituido un factor de control secundario controlando la descarga fluvial, la erosión y el aporte sedimentario. A partir del análisis de los perfiles longitudinales de los ríos, se identificó un posible bloque tectónico elevado por fallas, previamente desconocidas o poco documentadas, en el borde occidental de la cuenca del río de La Travesía. El mismo tipo de análisis también mostró una llamativa convexidad en el perfil longitudinal en un tramo con presencia de lecho rocoso en roca blanda en un río en el flanco oriental de la Sierra Alta de Zonda, a partir de lo cual se infirió una tasa de alzamiento tectónico localizada que supera a la tasa de erosión local. Por otra parte, la presencia de terrazas erosivas y de relleno cuaternarias únicamente en la margen derecha del río de La Ciénaga sugiere que el lineamiento que discurre paralelo a este río constituiría una posible estructura tectónicamente activa durante el Cuaternario tardío. En el piedemonte occidental de la Loma de Las Tapias la presencia de pliegues por propagación de falla y estratos de crecimiento en los depósitos aluviales datados en 8.330 a 8.180 años cal. AP, indica que la falla Villicum-Zonda presentaría actividad tectónica en el segmento comprendido entre la quebrada de Ullum y el extremo sur de la Loma de Ullum hasta al menos el Holoceno temprano. En el piedemonte occidental del extremo norte de la Sierra Chica de Zonda, se des

Reservoir Memory Complicates Water Management in the Upper Colorado River Basin - Ben Harding (SSRN Electronic Journal, 2019)

The effects of climate change and biodiversity loss on mutualisms - Annika S. Nelson (2019)
The abiotic environment drives species abundances and distributions both directly and indirectly through effects on multi-trophic species interactions. However, few studies have documented the individual and combined consequences of these direct and indirect effects. We studied an ant-tended aphid along an elevational gradient, where lower elevations were more arid. Hypotheses of stronger species interactions at lower elevations and a greater sensitivity of higher trophic levels to climate led us to predict increased top-down control of aphids by natural enemies (third trophic level) but even stronger protection from mutualist ants (fourth trophic level) with increasing aridity. As a result, we predicted that mutualism strength and aphid abundance would increase with aridity. We documented patterns of aphid abundance and tested for both the direct and multi-trophic indirect effects of aridity on aphid performance. To do so, we used both observational and manipulative methods across two years in replicate low and high elevation valleys, where summer temperatures decreased by 3.7°C and precipitation increased by 27 mm/mo from low to high elevations. Aphid colonies were 75% larger in the most (vs. least) arid sites, and this was best explained by changes in interactions with predators and ants. Aphids were unaffected by the direct effects of the abiotic environment or its indirect effects via host plant quality. In contrast, natural enemy effects increased with aridity; under ant exclusion, natural enemies had no effect on aphids in the least arid sites but depressed colony growth by 252% in the most arid sites. Ant activity also increased with aridity, with ants discovering more aphid colonies and experimental baits and allocating more foragers per aphid, although there was 5 no effect of aridity on ant abundance or community composition. Correspondingly, the mutualist services provided by ants increased with aridity; ants provided no benefits to aphids in the least arid sites but doubled colony growth in the most arid sites. In summary, an elevational cline in herbivore abundance was driven by a monotonic increase in trophic level sensitivity to aridity. These findings illustrate that predicting species responses to climate change will require a multi- trophic perspective.

Modeling transient soil moisture limitations on microbial carbon respiration - H. T. Hsu; K. B. Liu; J. L. Druhan; C. R. Lawrence; Matthew Winnick; Katharine Maher (Journal of Geophysical Research: Biogeosciences, 2019)
Abstract Soil microorganisms are known to survive periods of aridity and to recover rapidly after wetting events, with the ability to transition between a dormant state in dry conditions and an active state in wet conditions. Though this dynamic behavior has been previously incorporated into soil carbon respiration modeling frameworks, a direct comparison between this active‐dormant transition mechanism and a more simplified first‐order model has yet to be made. Here, we demonstrate the necessary extent of model complexity needed to reproduce transient carbon respiration rates obtained from a set of soil incubation experiments implemented over a range of soil depths and time intervals. Two approaches are tested, one uses simplified first‐order kinetics, whereas the other employs a transition between active and dormant biomass. The performance of each model is evaluated using an Akaike Information Criterion (AIC) based on the accuracy with which they reproduce an experimental dataset consisting of two sets of time series soil incubations collected across a range of time and depth resolutions. Based on the AIC evaluation and model‐data comparison, we conclude that a dormancy‐enabled model featuring two distinct microbial strategists performs best for the majority of the soil profile (above 108 cm) for both high and low depth resolution and sampling frequency, despite the added parameters required. In contrast, the first‐order model achieves better AIC scores when simulating our deepest soils (112–165 cm), where moisture fluctuations are expected to be less prevalent. These results guide how and where we choose to apply more cost intensive models.

Phenology as a process rather than an event: from individual reaction norms to community metrics - J. Ehrlen; N. C. Underwood; Brian D. Inouye (Ecological Monographs doi 10.1002/ecm.1352, 2019)
Abstract Measures of the seasonal timing of biological events are key to addressing questions about how phenology evolves, modifies species interactions, and mediates biological responses to climate change. Phenology is often characterized in terms of discrete events, such as a date of first flowering or arrival of first migrants. We discuss how phenological events that are typically measured at the population or species level arise from distributions of phenological events across seasons, and from norms of reaction of these phenological events across environments. We argue that individual variation in phenological distributions and reaction norms has important implications for how we should collect, analyze, and interpret phenological information. Regarding phenology as a reaction norm rather than one year's specific values implies that selection acts on the phenologies that an individual expresses over its lifetime. To understand how climate change is likely to influence phenology, we need to consider not only plastic responses along the reaction norm but changes in the reaction norm itself. We show that when individuals vary in their reaction norms, correlations between reaction norm elevation and slope make first events particularly poor estimators of population sensitivity to climate change, and variation in slopes can obscure the pattern of selection on phenology. We also show that knowing the shape of the distribution of phenological events across the season is important for predicting biologically important phenological mismatches with climate change. Last, because phenological events are parts of a continuous developmental process, we suggest that the approach of measuring phenology by recording developmental stages of individuals in a population at a single point in time should be used more widely. We conclude that failure to account for phenological distributions and reaction norms may lead to overinterpretation of metrics based on single events, such as commonly recorded first event dates, and may confound meta‐analyses that use a range of metrics. Rather than prescribing a single universal approach to studying phenology, we point out limitations of inferences based on single metrics and encourage work that considers the multivariate nature of phenology and more tightly links data collection and analyses with biological hypotheses.

Climate change shifts natural selection and the adaptive potential of the perennial forb Bochera stricta in the Rocky Mountians - Jordan B. Bemmels (Evolution, 2019)
Heritable genetic variation is necessary for populations to evolve in response to anthropogenic climate change. However, antagonistic genetic correlations among traits may constrain the rate of adaptation, even if substantial genetic variation exists. We examine potential genetic responses to selection by comparing multivariate genetic variance-covariances of traits and fitness (multivariate Robertson-Price identities) across different environments in a reciprocal transplant experiment of the forb Boechera stricta in the Rocky Mountains. By transplanting populations into four common gardens arrayed along an elevational gradient, and exposing populations to control and snow removal treatments, we simulated future and current climates and snowmelt regimes. Genetic variation in flowering and germination phenology declined in plants moved downslope to warmer, drier sites, suggesting that these traits may have a limited ability to evolve under future climates. Simulated climate change via snow removal altered the strength of selection on flowering traits, but we found little evidence that genetic correlations among traits are likely to affect the rate of adaptation to climate change. Overall, our results suggest that climate change may alter the evolutionary potential of B. stricta, but reduced expression of genetic variation may be a larger impediment to adaptation than constraints imposed by antagonistic genetic correlations.

Mapping the range shifts of East River Valley caddisflies (Trichoptera) - K. Wirebach (2019)
Range shifts occur when all individuals of a species or population move from a previously- habitable area to a newly-habitable area in response to changing environmental conditions. Climate- induced range shifts are well-documented for certain regions, biomes, and taxa, but large knowledge gaps exist for the Western Hemisphere and for aquatic macroinvertebrates specifically. There is a need to understand how climate-induced range shifts of aquatic macroinvertebrates are occurring, especially for taxa which have marked effects on ecosystem functioning, such as detritus shredders. Thirty years of aquatic sampling at the Rocky Mountain Biological Laboratory have revealed that Trichoptera species seem to be shifting their ranges, but the details of this observation have not been quantified. My project aimed to map and describe the multidimensional ranges (and later, range shifts) of caddisflies in this region using survey data and GIS technology. I mapped the current ranges of twelve species in the region and found results consistent with previous studies on life histories, predator vulnerability, and pond hydroperiod tolerance. I will continue this project as part of my senior thesis, which will specifically entail investigating previous ranges and describing range shifts through time and space. These results have several broad-scale implications. First, quantifying which new combinations of species are emerging across the landscape provides a jumping point to researchers wanting to study population and community studies focused on the interactions among species of caddisflies. Second, it also allows ecologists to ask new questions: what are the ecosystem functioning consequences of new community structuring with these taxa? What limits ranges and range shifts for these taxa?

Transitivity and structural balance in marmot social networks - T. W. Wey; F. Jordan; Daniel T. Blumstein (Behav Ecol Sociobiol, 2019)
Social relationships are composed of both positive (affiliative) and negative (agonistic) interactions, representing opposing effects. Social network theory predicts that positive relationships should be transitive; thus, the friend of a friend is more likely to be a friend. Further, when considering both positive and negative relationships jointly, structural balance theory predicts that certain configurations of positive and negative relationships in a triad are inherently less stable (unbalanced) and should tend to be eliminated. However, structural balance has been rarely examined in nonhuman social systems. We tested for transitivity and structural balance in social networks of socially flexible yellow-bellied marmots (Marmota flaviventer) and asked if group size, network density, or group composition affected the degree of structural balance. We found a consistent pattern of significant transitivity in positive interactions, some transitivity in negative interactions, and some evidence of structural balance. In particular, a Bweak^ definition of structural balance is probably more common than Bstrong^ structural balance, which used a stricter definition of balance. Network size limited the ability to detect these social processes, and smaller networks were less likely to show significant transitivity or structural balance. The proportion of adult females in a group affected the level of transitivity but did not affect the degree of structural balance. Our study suggests that there are intriguing similarities in social processes across diverse animal societies and that studying triads and network motifs may help identify basic social mechanisms linking local to global structure. Significance statement Social network theory predicts that basic social mechanisms should lead to similar structural properties across different societies. For example, positive relationships should be transitive (a friend of a friend is a friend), and certain combinations of positive and negative relationships represent conflict and should be unstable over time (e.g., a friend of a friend being an enemy is an unstable state). This latter theory, called structural balance, has rarely been examined in nonhuman societies; hence, we tested for transitivity and structural balance in groups of free-living yellow-bellied marmots. Positive interactions were generally transitive, but evidence for structural balance was inconsistent. Furthermore, group composition could affect network transitivity, and small network size (associated with few interactions) limits ability to detect significant patterns. Our results suggest that transitivity is fundamental in structuring positive relationships, while some forms of structural balance are present but not widespread.

Are Lek Disturbance Buffers Equitable for All Gunnison Sage-Grouse Populations? - Brian S. Cade; Melissa S. Siders; Kenneth W. Holsinger (Journal of Fish and Wildlife Management, 2019)
Abstract Lek disturbance buffers can be used to identify areas that provide important seasonal habitat for Gunnison sage grouse Centrocercus minimus (hereafter GUSG), a species with declining or vulnerable populations across their range. Lek disturbance buffers define areas around leks where anthropogenic disturbance is not permitted and have been considered for potential conservation strategies across GUSG habitat. Currently there is minimal information available on the effectiveness of the size of defined lek disturbance buffers. This study focused on two GUSG populations, the smaller Crawford population and a segment of the larger Gunnison Basin population. We utilized global positioning system location data on GUSG to evaluate seasonal use within three lek disturbance buffers, then compared and contrasted results between the two populations. The Crawford GUSG population showed increased movements from breeding season to late brood-rearing season and in winter returned to a usage pattern similar to the breeding season. Comparatively, the western Gunnison Basin GUSG population showed considerable movement throughout the entire year. In addition to these differences, we noted remarkable differences in distance between active leks, home range size, and total daily distance traveled between Crawford and western Gunnison Basin populations. Lek disturbance buffers created using the standard protocol provided varying protection depending on the distance between leks and number of leks. In small populations, the disturbance buffers overlapped each other, thus producing a smaller total lek disturbance buffer area. In addition to adding to the general body of knowledge of a little-studied species, our study had two important findings: 1) the use of empirical cumulative distribution demonstrated considerable differences in lek disturbance buffer use between the Crawford and the western Gunnison Basin populations, and 2) lek disturbance buffers did not provide equal protection for all populations on the basis of their current definition and derivation. We anticipate that land managers will find our results useful and informative when developing land management plans for the conservation of GUSG. Our analysis showed that the variability between populations and species is important for managers to consider when developing conservation strategies, especially for small populations.

Does the seedbank reflect the composition of the metacommunity for alpine plants? - G. Belfry (2019)
Community ecology and dynamics are often only thought of in terms of the processes selection and speciation. Likewise, plants are often only considered in their immobile, germinated form. However, when it comes to plant community dynamics, seeds and the seedbank are often critical in predicting community change through the processes of drift, and dispersal. The goal of this study is to analyze the relationship between the soil seedbank and the spatial and composition patterns across an alpine plant community. Ultimately, this study found a significant correlation between local vegetation abundance and seed abundance in a given sample, meaning that vegetative community composition plays an important role in community assemblage. The exact mechanism by which seed aggregation by vegetation occurs remains unknown, however this is a subject of current study. The results also suggested possible topographical or meteorological dispersal interactions, which are the subject of planned future study.

Does Aphis asclepiadis colony size mediate Formica rufa and Tapinoma sessile competition for mutualist aphids - N. T. Nguyen (2019)
Mutualisms are the species interaction in which both mutualist partners benefit from the relationship. Most mutualisms involve multiple interacting species and associating with multiple mutualist partners can be beneficial if they provide complementary benefits. Yet, mutualist species may also compete with each other for access to partners, which can alter the benefits the partner receives. Ant-aphid mutualism is a food-for-protection in which aphids produce honeydew to feed ants while ants provide aphids protection against predators. Previous studies of the aphid Aphis asclepiadis and two species of ants, Formica rufa and Tapinoma sessile, show that both ant species provide mutualistic services to aphids. However, aphid colonies tended by F. rufa are five-fold larger than colonies that tended by T. sessile, and the mechanisms driving this pattern are unclear. In this study, we tested whether aphid colonies tended by F. rufa are larger than those tended by T. sessile because (1) F. rufa is a better mutualist or (2) F. rufa competitively excludes T. sessile from tending large aphid colonies. We experimentally established large and small colonies of the aphid Aphis asclepiadis on the host plant Ligusticum porteri in three experimental ant manipulation treatments: open to all ants, F. rufa excluded, and all ants excluded. We recorded the number of aphids on the plants and the number and species of ants tending the aphids every three days for three weeks (21 days). Our results did not provide support for either of the two hypotheses. We found that F. rufa was not significantly more likely to select large aphid colonies to tend, and T. sessile was not significantly more likely to tend aphid colonies when F. rufa was excluded. We also found that the benefit F. rufa provided for the aphid colonies were more variable across the aphid colony life cycle compared to the benefits provided by T. sessile, and the overall benefit the aphid colonies received when they tended by F. rufa and T. sessile were not significantly different. By studying these interactions, we are one step closer to understand mutualism in multi-species context.

Depth- and time-resolved distributions of snowmelt-driven hillslope subsurface flow and transport and their contributions to surface waters. - Yeonju Kim; Benjamin Gilbert; Boris Faybishenko; Amanda Henderson; Jiamin Wan; Tetsu Tokunaga; Markus Bill; W. S. Brown; Wenming Dong; S. S. Hubbard; Kenneth Hurst Williams (Water Resources Research, 2019)
AbstractMajor components of hydrologic and elemental cycles reside underground, where their complex dynamics and linkages to surface waters are obscure. We delineated seasonal subsurface flow and transport dynamics along a hillslope in the Rocky Mountains (USA), where precipitation occurs primarily as winter snow and drainage discharges into the East River, a tributary of the Gunnison River. Hydraulic and geochemical measurements down to 10 m below ground surface supported application of transmissivity feedback of snowmelt to describe subsurface flow and transport through three zones: soil, weathering shale, and saturated fractured shale. Groundwater flow is predicted to depths of at least 176 m, although a shallower limit exists if hillslope‐scale hydraulic conductivities are higher than our local measurements. Snowmelt during the high snowpack water year 2017 sustained flow along the weathering zone and downslope within the soil, while negligible downslope flow occurred along the soil during the low snowpack water year 2018. We introduce subsurface concentration‐discharge (C‐Q) relations for explaining hillslope contributions to C‐Q observed in rivers and demonstrate their calculations based on transmissivity fluxes and measured pore water specific conductance and dissolved organic carbon. The specific conductance data show that major ions in the hillslope pore waters, primarily from the weathering and fractured shale, are about six times more concentrated than in the river, indicating hillslope solute loads are disproportionately high, while flow from this site and similar regions are relatively smaller. This methodology is applicable in different representative environments within snow‐dominated watersheds for linking their subsurface exports to surface waters.

Correlates of maternal glucocorticoid levels in a socially flexible rodent - A. Reese; G. M. Pinho; X. Ortiz Ross; Daniel T. Blumstein (Hormones and behavior, 2019)
While it is generally accepted that social isolation has detrimental effects on social species, little is known about the importance of social interactions in less social species-particularly for wild reproductive females. We studied socially-flexible yellow-bellied marmots (Marmota flaviventer) and asked whether features of the social environment are associated with maternal fecal glucocorticoid metabolite (FGM) concentrations. Since changes in maternal baseline glucocorticoids may have positive or negative consequences for offspring fitness, we were also interested in estimating their relationship with measures of reproductive success. We fitted generalized linear mixed effects models to a dataset including maternal FGM measurements, social network metrics, maternal/alloparental care, and pup FGM and survival. Agonistic interactions were positively associated with maternal FGM levels, while mothers that engaged in relatively more affiliative interactions had reduced FGM levels when living in environments with low predator pressure. Pups associated with mothers exhibiting high FGM levels had low annual survival rates, received less maternal/alloparental care and had higher FGM levels. Interestingly, offspring from mothers with high FGM levels were more likely to survive the summer when born in small litters. In sum, social interactions likely influence and are influenced by glucocorticoid levels of facultatively social females. Potential benefits of social bonds may be context-specific, and agonistic interactions may be tightly correlated with fitness. Female marmots exhibiting high FGM levels had overall low reproductive success, which is predicted by the cort-fitness hypothesis. However, under adverse conditions, offspring summer survival can be maximized if pups are born in small litters.

Progressive sensitivity of trophic levels to warming underlies an elevational gradient in ant–aphid mutualism strength - Cathrine Prenot; Jessica D. Pratt; Cole T. Symanski; Riley T. Pratt; Richard Alexander Smith; Kailen A. Mooney; Annika S. Nelson (Oikos, 2019)
Although species interactions are often proposed to be stronger at lower latitudes and elevations, few studies have evaluated the mechanisms driving such patterns. In this study, we assessed whether, and by which mechanisms, abiotic changes associated with elevation altered the outcome of an ant–aphid protection mutualism. To do so, we characterized the multi‐trophic interactions among the ant Formica podzolica , the aphid Aphis varians , and aphid natural enemies occurring on the plant Chamerion angustifolium within replicate high and low elevation valleys. Low (versus high) elevation sites had longer summers (snowmelt 13 days earlier) and were on average 1.1°C warmer and 41% drier throughout the year. At low elevations, individual ant colonies consumed approximately double the volume of carbohydrate baits, likely due to a higher foraging tempo, and possibly due to a greater demand for sugar‐ versus protein‐rich resources (as indicated by stable isotope analysis). Wild aphid colonies at low elevations were visited by 1.4‐fold more natural enemies (controlling for variation in aphid abundance), while experimental aphid colonies on potted plants were tended 52% more frequently by ants. As a result, ants increased aphid colony survival by 66% at low elevations but had no detectable effect at high elevations; at low (versus high) elevations aphid colonies without ants had lower survival, demonstrating stronger predator effects, while aphid colonies with ants had higher survival, demonstrating even stronger ant benefits. Analyses for the effects of mean summer temperature yielded qualitatively identical results to those based on elevation. Collectively, these findings support predictions for a greater sensitivity of higher trophic levels to warming and demonstrate how species interactions can vary across environmental gradients due to simultaneous changes in species traits and abundances across multiple trophic levels.

Heterogeneity in Hyporheic Flow, Pore Water Chemistry, and Microbial Community Composition in an Alpine Streambed - R. S. Gabor; K. D. Harris; C. M. Saup; Audrey Sawyer; S. R. Bryant; Michael J. Wilkins; Martin Briggs; Annika S. Nelson; Kenneth Hurst Williams (JGR: Biogeosciences, 2019)
AbstractThe hyporheic zone, where surface water and groundwater mix, is an important microbial habitat where biogeochemical reactions influence water quality. We show that spatial variability in hyporheic flow in the East River near Crested Butte, CO, drives heterogeneity in streambed geochemical conditions and microbial community assemblages, but the diversity of microbial assemblages remains nearly constant throughout the reach. In July 2018, we collected approximately 100 pore water samples at 20‐cm depth and analyzed them for anions, cations, dissolved organic carbon, dissolved organic matter (DOM) quality, and basic water quality parameters. Vertical hydraulic head gradients were also measured to assess the potential for upward or downward flow, and heat tracing was used to quantify vertical flux rates at a subset of locations. We found that regions of the streambed that are more groundwater‐dominated contain less dissolved oxygen, higher concentrations of reduced metals, and more microbially processed, recalcitrant DOM, while more surface water‐dominated locations contain higher dissolved oxygen concentrations and terrestrially derived, labile DOM. 16S rRNA gene sequencing of extracted DNA revealed that microbial community composition varies with geochemical gradients related to hyporheic flow. These findings provide a better understanding of hyporheic controls on streambed biogeochemistry during the baseflow season, which is expected to lengthen with climate change in alpine watersheds due to earlier snowmelt onset and reduced snowpack.

Exploring source water mixing and transient residence time distributions of outflow and evapotranspiration with an integrated hydrologic model and Lagrangian particle tracking approach - L. A. Bearup; L. E. Condon; M. Danesh-Yazdi; Reed M. Maxwell (Ecohydrology, 2019)
Abstract Understanding the time water takes as it moves from rain or snowmelt through the terrestrial system to arrive as stream discharge, or evapotranspiration (ET) is an important hydrologic quantity. We develop a Lagrangian particle tracking method to capture transient residence times from source to either ET or outflow in an integrated hydrologic model. This method is parallel and efficiently captures time evolution of parcels of water in the model and tracks the source of water for hydrograph or ET separation. We demonstrate this model using hypothetical hillslope simulations driven by snow or rain dominated forcing and two different land cover types. We show that land cover and forcing both impact the outflow residence time distribution, which spans many years. We also introduce the idea of ET residence time distributions and show that while mean ET residence times are typically less than 1 year, land cover affects this quantity and simulated ET processes draw from much older water (many years old) depending on location on the hillslope or seasonal cycle. Finally, we study source water contribution to outflow and ET and explore assumptions about a residence time‐based definition of older, pre‐event, or groundwater end member. We show that simulated plant processes may switch to more opportunistic and younger sources of water, changing the composition of outflow.

Plant Identity Influences Foliar Fungal Symbionts More Than Elevation in the Colorado Rocky Mountains - D. L. Taylor; Melanie R Kazenel; Jennifer A. Rudgers; Stephanie N. Kivlin; Joshua S. Lynn (Microbial Ecology, 2019)
Despite colonizing nearly every plant on Earth, foliar fungal symbionts have received little attention in studies on the biogeog- raphy of host-associated microbes. Evidence from regional scale studies suggests that foliar fungal symbiont distributions are influenced both by plant hosts and environmental variation in climate and soil resources. However, previous surveys have focused on either one plant host across an environmental gradient or one gradient and multiple plant hosts, making it difficult to disentangle the influence of host identity from the influence of the environment on foliar endophyte communities. We used a culture-based approach to survey fungal symbiont composition in the leaves of nine C3 grass species along replicated elevation gradients in grasslands of the Colorado Rocky Mountains. In these ecosystems, the taxonomic richness and composition of foliar fungal symbionts were mostly structured by the taxonomic identity of the plant host rather than by variation in climate. Plant traits related to size (height and leaf length) were the best predictors of foliar fungal symbiont composition and diversity, and composition did not vary predictably with plant evolutionary history. The largest plants had the most diverse and distinctive fungal communities. These results suggest that across the ~ 300 m elevation range that we sampled, foliar fungal symbionts may indirectly experience climate change by tracking the shifting distributions of plant hosts rather than tracking climate directly.

Timber Losses from West Fork Complex Fire in Southwest Colorado - Kevin Duda; Laren Cyphers; Kurt Mackes (Forest Products Journal, 2019)
Abstract This article provides an assessment of fire effects on timber burned in the West Fork Complex fire area, located in the San Juan Mountains of Colorado. The West Fork Complex fire burned 109,615 acres in 2013, and suppression costs alone totaled $33.2 million. Much of the fire occurred in spruce–fir forests that were previously affected by spruce beetle (Dendroctonus rufipennis). Several timber sales were actively occurring within the fire footprint, and more were anticipated to begin in subsequent years. To provide a more accurate valuation estimate, base log stumpage data from 2003 through 2017 were included in this study to show high degrees of variation over time. With base log stumpage values determined, estimates of total hundred cubic feet of each significant species were calculated using geospatial and forest inventory analysis data. This study determined the timber value loss resulting from the coupled disturbance events of the spruce beetle epidemic and a wildland fire to be $19,083,102. This estimate will allow for a more accurate valuation of the actual damage resulting from the West Fork Complex fire. This study may also be useful in supporting the literary basis for salvage and fuels management after a beetle outbreak to prevent such timber value losses from occurring.

Are Marmot Alarm Class Condition Dependent? - A. L. Nash (2019)
The production and structure of animal signals may be condition dependent and may provide more than one type of information to receivers. While alarm calls are not typically viewed as condition dependent, recent studies have suggested that their structure and possibly their propensity to be emitted depends on condition and state. We asked whether the propensity of yellow-bellied marmots (Marmota flaviventer) to emit calls is influenced by their immunological or parasite status, by quantifying both trap-elicited and natural calling rates as a function of their neutrophil to lymphocyte (NL) ratio, the presence of a blood borne trypanosome, and the presence of several intestinal parasites (Eimeria, Entamoeba, and Ascaris). We built linear mixed effects models to determine if the health measures we collected were associated with the probability of calling in a trap and with annual rates of wild alarm calling. Marmots infected with trypanosomes were marginally more likely to call when trapped and called naturally at Nash 2 significantly higher rates. Ascaris was negatively associated with the probability of calling when trapped. NL ratio was not directly associated with in trap calling probability, but males were more likely to call when they had higher NL ratios. Thus, internal conditions such as parasite infection and immune system activation can modulate the production of alarm signals and thus provide potential information to both predators and prey about the caller’s condition.

Reproductive losses due to climate change? Induced earlier flowering are not the primary threat to plant population viability in a perennial herb - A. M. Anderson; Aldo Compagnoni; Jennifer L. Williams; Tom E. X. Miller; Amy M. Iler; David W. Inouye; Paul J. CaraDonna (Journal of Ecology, 2019)
Abstract Despite a global footprint of shifts in flowering phenology in response to climate change, the reproductive consequences of these shifts are poorly understood. Furthermore, it is unknown whether altered flowering times affect plant population viability. We examine whether climate change‐induced earlier flowering has consequences for population persistence by incorporating reproductive losses from frost damage (a risk of early flowering) into population models of a subalpine sunflower (Helianthella quinquenervis). Using long‐term demographic data for three populations that span the species’ elevation range (8–15 years, depending on the population), we first examine how snowmelt date affects plant vital rates. To verify vital rate responses to snowmelt date experimentally, we manipulate snowmelt date with a snow removal experiment at one population. Finally, we construct stochastic population projection models and Life Table Response Experiments for each population. We find that populations decline (λs < 1) as snowmelt dates become earlier. Frost damage to flower buds, a consequence of climate change‐induced earlier flowering, does not contribute strongly to population declines. Instead, we find evidence that negative effects on survival, likely due to increased drought risk during longer growing seasons, drive projected population declines under earlier snowmelt dates. Synthesis. Shifts in flowering phenology are a conspicuous and important aspect of biological responses to climate change, but here we show that the phenology of reproductive events can be unreliable measures of threats to population persistence, even when earlier flowering is associated with substantial reproductive losses. Evidence for shifts in reproductive phenology, along with scarcer evidence that these shifts actually influence reproductive success, are valuable but can paint an incomplete and even misleading picture of plant population responses to climate change.

Stoichiometry and infectious disease: Linking chemical elements and parasitic interactions - A. J. Sanders (2019)
A growing body of work has shown that parasites’ growth and reproduction can be influenced by the food quality available to their hosts. Consumers, including parasites, require a balanced diet to grow. Unlike many consumers, however, parasites are beholden to the diet quality presented to them by their host, which is in turn a function of the host’s own diet. Here, we tested the hypothesis that the relationship between parasite reproduction and host diet quality is subject to a threshold elemental ratio: that there is a balanced host diet that confers maximum growth to the parasite. We present results from a laboratory experiment where we fed a wide range of experimental diets to Tubifex tubifex infected with Myxobolus cerebralis and observed a hump-shaped relationship between M. cerebralis spore production and T. tubifex diet stoichiometry, indicative of a threshold elemental ratio. Further we compared these results to M. cerebralis spore production by wild T. tubifex, and found that spore production in the wild T. tubifex was characterized by a linear relationship with T. tubifex diet. Together, our results show 13 that host diet stoichiometry can be an important influence on parasite reproduction, but that the relationship between them is complex and sometimes nonlinear. 14

Investigating Microtopographic and Soil Controls on a Mountainous Meadow Plant Community Using High-Resolution Remote Sensing and Surface Geophysical Data - E. Léger; J. C. Rowland; John Peterson; Chelsea Wilmer; Heidi Steltzer; Nicola Falco; Baptiste Dafflon; Haruko M. Wainwright; S. S. Hubbard; Kenneth Hurst Williams (Journal of Geophysical Research: Biogeosciences, 2019)
AbstractThis study aims to investigate the microtopographic controls that dictate the heterogeneity of plant communities in a mountainous floodplain‐hillslope system, using remote sensing and surface geophysical techniques. Working within a lower montane floodplain‐hillslope study site (750 m × 750 m) in the Upper Colorado River Basin, we developed a new data fusion framework, based on machine learning and feature engineering, that exploits remote sensing optical and light detection and ranging (LiDAR) data to estimate the distribution of key plant meadow communities at submeter resolution. We collected surface electrical resistivity tomography data to explore the variability in soil properties along a floodplain‐hillslope transect at 0.50‐m resolution and extracted LiDAR‐derived metrics to model the rapid change in microtopography. We then investigated the covariability among the estimated plant community distributions, soil information, and topographic metrics. Results show that our framework estimated the distribution of nine plant communities with higher accuracy (87% versus 80% overall; 85% versus 60% for shrubs) compared to conventional classification approaches. Analysis of the covariabilities reveals a strong correlation between plant community distribution, soil electric conductivity, and slope, indicating that soil moisture is a primary control on heterogeneous spatial distribution. At the same time, microtopography plays an important role in creating particular ecosystem niches for some of the communities. Such relationships could be exploited to provide information about the spatial variability of soil properties. This highly transferable framework can be employed within long‐term monitoring to capture community‐specific physiological responses to perturbations, offering the possibility of bridging local plot‐scale observations with large landscape monitoring.

Ecosystem Consequences of Soil Warming - John Harte (2019)

Effects of pond permanence on avian behaviors - L. Braun (2019)
As global temperatures rise due to climate change, aquatic ecosystems, such as alpine ponds, become more at risk of drying earlier than normal. These changes in pond hydrology have the potential to alter not only the aquatic ecosystems, but also terrestrial and riparian ecosystems, through resource subsidies provided by the ponds. Vernal ponds (temporary ponds) are particularly vulnerable to these changes due to their size, therefore making the surrounding terrestrial ecosystems susceptible as well. Through observing avian behaviors around both permanent and temporary ponds, our study strived to gain insight on how terrestrial predators react to the change of aquatic hydrology. Our preliminary results indicate that avian predators spend more total time near semi-permanent ponds, but further inclusion of habitat variables, such as pond size, may change these results. Understanding the causes and effects of climate altered hydrology are important in building conservation strategies for aquatic and terrestrial ecosystems as global warming persists and grows in influence.

Two-year bee or not two-year bee? How voltinism is affected by temperature and season length in a high-elevation solitary bee - Regan Cross; Jessica R.K. Forrest; Paul J. CaraDonna (American Naturalist, 2019)
Organisms must often make developmental decisions without complete information about future conditions. This uncertainty-for example, about the duration of conditions favorable for growth-can favor bet-hedging strategies. Here, we investigated the causes of life cycle variation in Osmia iridis, a bee exhibiting a possible bet-hedging strategy with co-occurring 1- and 2-year life cycles. One-year bees reach adulthood quickly but die if they fail to complete pupation before winter; 2-year bees adopt a low-risk, low-reward strategy of postponing pupation until the second summer. We reared larval bees in incubators in various experimental conditions and found that warmer-but not longer-summers and early birthdates increased the frequency of 1-year life cycles. Using in situ temperature measurements and developmental trajectories of laboratory- and field-reared bees, we estimated degree-days required to reach adulthood in a single year. Local long-term (1950-2015) climate records reveal that this heat requirement is met in only ∼7% of summers, suggesting that the observed distribution of life cycles is adaptive. Warming summers will likely decrease average generation times in these populations. Nevertheless, survival of bees attempting 1-year life cycles-particularly those developing from late-laid eggs-will be <100%; consequently, we expect the life cycle polymorphism to persist.

Context dependent biotic interactions control plant abundance across altitudinal environmental gradients - Melanie R Kazenel; Stephanie N. Kivlin; Jennifer A. Rudgers; Joshua S. Lynn (Ecography, 2019)
Climate change is causing species with non-overlapping ranges to come in contact, and a key challenge is to predict the consequences of such species re-shuffling. Experiments on plants have focused largely on novel competitive interactions; other species interactions, such as plant–microbe symbioses, while less studied, may also influence plant responses to climate change. In this greenhouse study, we evaluated interactions between soil microbes and alpine-restricted plant spe- cies, simulating a warming scenario in which low-elevation microbes migrate upslope into the distribution of alpine plants. We examined three alpine grasses from the Rocky Mountains, CO, USA (Poa alpina, Festuca brachyphylla, and Elymus scribneri). We used soil inocula from within (resident) or below (novel) the plants’ current elevation range and examined responses in plant biomass, plant traits, and fungal colonization of roots. Resident soil inocula from the species’ home range decreased biomass to a greater extent than novel soil inocula. The depressed growth in resident soils suggested that these soils harbor more carbon-demanding microbes, as plant biomass generally declined with greater fungal colonization of roots, especially in resident soil inocula. Although plant traits did not respond to the provenance of soil inocula, specific leaf area declined and root:shoot ratio increased when soil inocula were sterilized, indicating microbial mediation of plant trait expression. Contrary to current predictions, our findings suggest that if upwardly migrating microbes were to displace current soil microbes, alpine plants may benefit from this warming-induced microbial re-shuffling.

From grain to floodplain: Evaluating heterogeneity of floodplain hydrostratigraphy using sedimentology, geophysics, and remote sensing - H. F. Malenda (2019)
Floodplain stratigraphy, a major structural element of alluvial aquifers, is a fundamental component of floodplain heterogeneity, hydraulic conductivity, and connectivity. Watershed-scale hydrological models often simplify floodplains by modeling them as largely homogeneous, which inherently overlooks natural floodplain heterogeneity and anisotropy and their effects on hydrologic processes such as groundwater flow and transport and hyporheic exchange. This study, conducted in the East River Basin, Colorado, USA, combines point-, meander-, and floodplain-scale data to explore the importance of detailed field studies and physical representation of alluvial aquifers. We combine sediment core descriptions, hydraulic conductivity estimates from slug tests, ground-penetrating radar (GPR), historical maps of former channels, LiDAR- based elevation and Normalized Difference Vegetation Index data to infer 3-D fluvial stratigraphy. We compare and contrast stratigraphy of two meanders with disparate geometries to explore floodplain heterogeneity and connectivity controls on flow and transport. We identify buried point bars, former channels, and overbank deposits using GPR, corroborated by point sediment descriptions collected during piezometer installment and remotely sensed products. We map heterogeneous structural features that should control resultant flow and transport; orientation and connectivity of these features would control residence times important in hydrologic models. iii

Stridulation in Nicrophorus investigator as a Possible Means of Cooperation during Carcass Sequestration - O. Ortuno (2019)
Burying beetle stridulation has been observed and documented when caring for their young, as well as among agonistic beetles competing for carrion. Burying beetles in the genus Nicrophorus require a small carcass, typically 16-50 grams, in order to reproduce. Once located, the carcass is buried by the burying beetles, after which the beetles lay their eggs in the underground chamber and partake in biparental care. This study found that N. investigator pairs use stridulation during carcass sequestration when faced with an obstacle, but found no significant difference between the beetles’ use of stridulation and lack thereof in terms of their ability to move carrion.

Adaptive gene regulation in wild mammals exposed to high predator abundance - S. W. Cole; Tiffany Armenta; Robert Wayne; Daniel T. Blumstein (Animal Behaviour, 2019)
Psychological stress induced by exposure to predators has complex effects on the behaviour and physiology of prey species. This includes potential influences on gene expression mediated via stress-responsive physiological pathways such as the sympathetic nervous system and hypothalamus–pituitary–adrenal (HPA) axis. Laboratory studies have documented diverse transcriptional effects of predator-induced fear, but genomic responses to predator exposure in the wild remain poorly understood. Here, we used RNA-sequencing to investigate the leukocyte transcriptome response to chronic predator pressure in a well-studied population of wild yellow-bellied marmots, Marmota flaviventer. We assessed the genomic response to this stressor in three ways by (1) identifying differentially expressed individual genes across the genome, (2) assessing whether differentially expressed genes were statistically over-represented by functional categories and (3) testing for transcription factor activity that may mediate observed gene expression differences. We found 349 individual genes regulated in association with chronic predator presence, including transcripts known to regulate heat shock proteins, metabolism and DNA damage repair. Gene ontology analysis revealed that the majority of these differentially expressed genes were involved with the cellular response to stress, cellular metabolism and protein transport. Transcription factor analysis implicated glucocorticoid signalling in mediating these effects. Our work confirms that the physiological response to predator-induced stress is complex, initiating transcriptional activity in multiple processes and pathways. In addition to the canonical expectations that individuals exposed to predators mobilize HPA signalling and homeostasis pathways, we also detected activity in genes typically associated with human anxiety and cerebral function. This is the first study to demonstrate that leukocyte transcriptomes taken from animals living in a natural environment can reflect the complex ecology of fear.

Experimentally determined solute release rates from variably metamorphosed shale : implications for weathering in the East River watershed, CO. - James McGuinness (Digital Collections of Colorado (Colorado State University), 2019)
This study investigates the variability in solute release rates from samples of shale and slate with variable lithology resulting from contact metamorphism. Mineral dissolution column experiments are used to test the hypothesis that solute release rates will vary with metamorphic grade of Mancos Shale samples collected from the East River watershed in southcentral Colorado. To test if there is variation in solute release rates correlating to metamorphic grade in the East River watershed; flow through column experiments were performed at ambient temperatures ( 25C) in clear, acrylic columns with an internal diameter of 2.54 cm and a column length of 30.48 cm. The following synthetic rain water solution was mixed in 15 L batches: 4.07 mg NaNO3, 3.24 mg NaCl, 0.35 mg KCl,1.65 mg CaCl2  H2O, 2.98 mg MgSO4  7H2O, and 3.41 mg (NH4)2SO, per liter of deionized water. Lithium triazide at .05% by volume was added to the input solution to prevent bacterial growth (Neaman et al, 2004). The synthetic rain water solution was pumped through the columns and effluent samples were collected at approximately 24-hour intervals for 20-24. Mancos Shale in the East River watershed has been impacted by contact metamorphism. Mineral compositions have been altered from this metamorphism. The East River Mancos Shale samples are separated into three qualitative groups the highest metamorphosed, moderately metamorphosed, and least metamorphosed. Compositional differences in the bulk mineralogy of metamorphosed samples compared to unmetamorphosed samples are linked to differences in the steady state release of solutes.

Niche breadth changes in response to environmental perturbation: the impact of early snowmelt on subalpine plant-pollinator specialization - E. Sharer (2019)
With global climate change, we observe phenological changes across all ecosystems. In the Colorado Rocky Mountains, warming is resulting in lower snowpack and earlier spring melt. Since plants use snow melt timing as a cue to start growing, climate change is implicated in accelerated bloom time and thus has the potential to cause a phenological mismatch between plants and their pollinators. To account for this mismatch, pollinators may change the plant species they interact with (i.e. their niche breadth) to account for the difference in timing of floral resources. This could include wholescale switching to a new resource, changing the number of species they visit, or instead could change the frequency of their visits to different plants. In this study, we investigated the impact of an environmental perturbation on plant-pollinator niche breadth, focusing on if and how niche breadth changes. We perturbed the system by inducing a phenological change by manipulating the timing of snowmelt which in turn accelerated bloom time by approximately two weeks. Our study thus tested for a phenological mismatch between plants and pollinators. Under this manipulation, in accelerated-snowmelt plots, we found that pollinators foraged on more diverse plants while maintaining the number of plant species they visited. We expect pollinators to expand their niche breadth in order to receive enough floral resources. In changing their own niche breadth, pollinators also broaden plant niche breadth. Consequently, we expect both plants and pollinators to face uncertainties and challenges due to phenological change.

Carbon Dioxide Concentrations and Efflux from Permanent, Semi-Permanent, and Temporary Subalpine Ponds - S. Campbell; A. G. DelVecchia; D. C. West; J. A. Balik; B. W. Taylor; S. A. Wissinger (Wetlands, 2019)
Small ponds account for a disproportionately high percentage of carbon dioxide emissions relative to their small surface area. It is therefore crucial to understand carbon flow in these ponds to refine the current global carbon budget, especially because climate change is affecting pond hydrology. High elevation ponds in the Elk Mountains of western Colorado are drying more frequently as the timing of snowmelt advances. We compared CO2 concentrations and fluxes among ponds of different hydroperiods over diel sampling periods during the course of the 2017 open-water period. CO2 concentrations were significantly negatively correlated with pond depth and averaged 77.6 ± 24.5 μmol L−1 (mean ± S.E.) across all ponds and sampling events. Ponds were up to twenty times supersaturated in CO2 with respect to the atmosphere. Flux was highly variable within individual ponds but correlated with time of sampling and was highest at night. Flux averaged 19.7 ± 18.8 mg CO2 m−2 h−1 across all ponds and sampling events. We also compared flux values obtained using modeled and empirical methods and found that widely-applied models of gas exchange rates using wind-based gas exchange (K) values yielded estimates of CO2 flux that were significantly higher than those obtained using the floating chamber approach, but estimates of CO2 flux using globally averaged convection- based K values were lower than those obtained using the floating chambers. Lastly, we integrated soil vs. water efflux measure- ments with long-term patterns in hydrology to predict how total season-long efflux might change under the more rapid drying regimes and longer seasons that are already occurring in these systems. Because soil CO2 efflux averaged 277.0 ± 49.0 mg CO2 m−2 h−1, temporary ponds emitted 674.1 ± 99.4 kg CO2 m−2 over the course of the 2017 season from ice-out to refreezing, which was over twice as much as permanent and semi-permanent ponds. Our results emphasize that contributions of CO2 from small ponds to the global carbon budget estimates will vary with pond hydroperiod and sampling methodology, which have been overlooked given that most previous estimates were collected from limited sampling periods and from pond waters alone. Furthermore, pond CO2 contributions are predicted to increase over time as pond areas transition from efflux from water to efflux from soil.

New County Records of Aedes aegypti and Aedes epactius in Colorado - John-Paul Mutebi; Erik M. Ostrum (Journal of the American Mosquito Control Association, 2019)
ABSTRACT In August and September 2017, we conducted mosquito surveillance in southeastern Colorado by using ovitraps and larval sampling. The aim was to determine if there were established populations of Aedes aegypti and Ae. albopictus in the region. A single female Ae. aegypti was reared from eggs collected in La Junta, CO, but Ae. albopictus was not detected. Three other species were reared from eggs and/or larvae: Ae. epactius, Culex restuans, and Cx. pipiens. Aedes aegypti and Ae. epactius were detected for the 1st time in Otero and Baca counties, respectively, and these became new county records for Colorado. Both species were detected in very low numbers, suggesting extremely low population density or sporadic introductions into southeastern Colorado.

Comparing predictive measures and model functions for estimating plant biomass: lessons from a sagebrush–rabbitbrush community - Joshua B. Grinath (Plant Ecology, 2019)
It is indicated that accurate predictive models of forb and shrub biomass can frequently be easily obtained using simple linear regression and cover or volume data.

Quantifying Nectar Resources in Bumble Bee Visited Plants - G. Kirschke (2019)
Native bumble bees play key roles in their ecosystems as pollinators, but little is known about the quantity and quality of floral resources on which they depend in natural areas across a season. Additionally, how those resources might be affected by abiotic factors, many of which are being altered under climate change, is poorly understood. To address this knowledge gap, we quantified nectar resources for bumble bee visited plant species in subalpine meadows. Specifically, we (1) examined interspecific variation in nectar resources, (2) compared nectar resources across wet and dry meadow conditions, and (3) examined intraspecific variation in nectar resources between years. Nectar volume, sugar concentration, and sugar content (“nectar traits”) were variable across species, within species, and in response to both local and annual water availability. This research clarifies the relative contributions of plant species to the resource landscape available for bumble bees, and how this resource landscape may respond to variation in abiotic conditions.

Gene expression shifts in yellow-bellied marmots prior to natal dispersal - D. H. Geschwind; Tiffany Armenta; D. N. Cole; Robert Wayne; Daniel T. Blumstein (Behavioral Ecology, 2019)
The causes and consequences of vertebrate natal dispersal have been studied extensively, yet little is known about the molecular mechanisms involved. We used RNA-seq to quantify transcriptomic gene expression in blood of wild yellow-bellied marmots (Marmota flaviventer) prior to dispersing from or remaining philopatric to their natal colony. We tested 3 predictions. First, we hypothesized dispersers and residents will differentially express genes and gene networks since dispersal is physiologically demanding. Second, we expected differentially expressed genes to be involved in metabolism, circadian processes, and immune function. Finally, in dispersing individuals, we predicted differentially expressed genes would change as a function of sampling date relative to dispersal date. We detected 150 differentially expressed genes, including genes that have critical roles in lipid metabolism and antigen defense. Gene network analysis revealed a module of 126 coexpressed genes associated with dispersal that was enriched for extracellular immune function. Of the dispersal-associated genes, 22 altered expression as a function of days until dispersal, suggesting that dispersal-associated genes do not initiate transcription on the same time scale. Our results provide novel insights into the fundamental molecular changes required for dispersal and suggest evolutionary conservation of functional pathways during this behavioral process.

The impacts of long term warming on potential soil microbial activity across soil depth - F. K. Quan-Shau (2019)
Terrestrial soils store more carbon than exists in the atmosphere and all plant life combined. Thus, small changes in the amount of carbon stored in soil or released back to the atmosphere from soil can have large impacts on atmospheric carbon concentrations and climate change. As climate change progresses, warming temperatures are projected to increase soil microbial activity, leading to shifts in soil carbon accumulation and stabilization. Here, we sampled soils across the soil profile during the decommissioning of a 30-year warming experiment conducted in a subalpine meadow to understand the degree to which warming impacts carbon losses in both surface soils and soils deep within the soil profile.

Lifetime Fitness, Sex-Specific Life History, and the Maintenance of a Polyphenism - Michael P. Moore; Ashley Hagan; Jacqueline Doyle; Morgan Geile; N. Gerlane; Christopher Eden; A. C. R. Lackey; Howard Whiteman (The American Naturalist, 2019)
Polyphenisms-alternative morphs produced through plasticity-can reveal the evolutionary and ecological processes that initiate and maintain diversity within populations. We examined lifetime fitness consequences of two morphs in a polyphenic population of Arizona tiger salamanders using a 27-year data set with 1,317 adults and 6,862 captures across eight generations. Larval salamanders develop into either an aquatic paedomorph that retains larval traits and stays in its natal pond or a terrestrial metamorph that undergoes metamorphosis. To evaluate the adaptive significance of this polyphenism, we compared lifetime reproductive success of each morph and assessed how life-history strategies and spatiotemporal variation explained fitness. We found sex-specific differences in lifetime fitness between morphs. For males, paedomorphs had more reproductive opportunities than metamorphs when we accounted for the potential mating advantage of larger males. For females, in contrast, metamorphs had higher estimated egg production than paedomorphs. Life-history strategies differed between morphs largely because the morphs maximized different ends of the trade-off between age at first reproduction and longevity. Spatiotemporal variation affected larval more than adult life-history traits, with little to no effect on lifetime fitness. Thus, environmental variation likely explains differences in morph production across time and space but contributes little to lifetime fitness differences between morphs and sexes. Our long-term study and measures of lifetime fitness provide unique insight into the complex selective regimes potentially acting on each morph and sex. Our findings motivate future work to examine how sex-specific selection may contribute to the maintenance of polyphenism.

Advanced phenology of higher trophic levels shifts aphid host plant preferences and performance - M. L. Mullins (2019)
The abundance of insect herbivores, such as aphids, is mediated by interactions with

Plant chemical mediation of ant behavior - N. C. Acosta; Kailen A. Mooney; Annika S. Nelson (Current Opinion in Insect Science, 2019)
Ants are ecologically dominant members of terrestrial communities. Ant foraging is often strongly associated with plants and depends upon associative learning of chemicals in the environment. As a result, plant chemicals can affect ant behaviors and, in so doing, have strong multi-trophic indirect effects. Plant chemicals mediate ant behaviors in the contexts of floral visitation, seed dispersal and predation, leaf cutting, interactions with ant-mutualist host plants, interactions with mutualist and prey insects in plant canopies, and plant predation of ants by carnivorous plants. Here, we review what is known about these differing contexts in which plant chemicals influence ant behavior, the mechanisms by which ants are affected by plant chemicals, and future directions within these topics.

Rising Temperatures Reduce Colorado River Flow - Sarah Stanley (Eos, 2019)
Hotter conditions have played a much greater role in reducing flow during the ongoing Millennium Drought than in a mid-20th century drought.

Pollinator Community Compositions Across Four Subalpine Plant Species - V. DeLira (2019)
Studies have shown that there have been pollinator declines occurring worldwide (e.g., Beismiejer et al. 2006; Potts et al. 2010; Burkle et al. 2013; Goulson et al. 2015). It is important to understand plant-pollinator interactions as thoroughly as possible, including which species are interacting with each other, to understand the possible consequences that may follow these declines. which prompts a number of problems considering their importance in plant reproduction. The primary objective of this study was to explore the variation in pollinator visitation rates and community composition across four subalpine species that bloom sequentially throughout the summer growing season. This study was conducted at the Rocky Mountain Biological Laboratory (RMBL) located at Gothic, Colorado. Timed pollinator observations of various patches of four subalpine plant species, Delphinium nuttallianum, Hydrophyllum fendleri, Erigeron speciousus and Potentilla pulcherrima, throughout their flowering periods between June and early August showed that pollinator communities are composed by visitation rates, alpha-diversity, and beta-diversity. This information will provides basic information on the type and frequency of visiting pollinators over time and across plants with their various shapes, blooming times, colors, and elevation. The secondary objective of this study was to create an understanding of how pollinator exclusion bags affect studies in which the bags are used to simulate decreased pollination. Observations were made as the ones previously mentioned of plots that have the same four plants with some flowers covered by pollinator exclusion bags compared to plots with no bags. These plots are under the Iler-CaraDonna study looking at the effect of pollinator declines on plant reproduction. This secondary objective showed that there does not appear to be an effect of the pollinator exclusion bags on pollinator foraging behavior. DeLira: POLLINATOR COMMUNITY COMPOSITIONS ACROSS FOUR SUBALPINE PLANT SPECIES 3

Soil microbes that may accompany climate warming increase alpine plant production - D. A. Duarte; Jennifer A. Rudgers; Joshua S. Lynn (Oecologia, 2019)
Climate change is causing species with non-overlapping ranges to come in contact, and a key challenge is to predict the consequences of such species re-shuffling. Experiments on plants have focused largely on novel competitive interactions; other species interactions, such as plant–microbe symbioses, while less studied, may also influence plant responses to climate change. In this greenhouse study, we evaluated interactions between soil microbes and alpine-restricted plant spe- cies, simulating a warming scenario in which low-elevation microbes migrate upslope into the distribution of alpine plants. We examined three alpine grasses from the Rocky Mountains, CO, USA (Poa alpina, Festuca brachyphylla, and Elymus scribneri). We used soil inocula from within (resident) or below (novel) the plants’ current elevation range and examined responses in plant biomass, plant traits, and fungal colonization of roots. Resident soil inocula from the species’ home range decreased biomass to a greater extent than novel soil inocula. The depressed growth in resident soils suggested that these soils harbor more carbon-demanding microbes, as plant biomass generally declined with greater fungal colonization of roots, especially in resident soil inocula. Although plant traits did not respond to the provenance of soil inocula, specific leaf area declined and root:shoot ratio increased when soil inocula were sterilized, indicating microbial mediation of plant trait expression. Contrary to current predictions, our findings suggest that if upwardly migrating microbes were to displace current soil microbes, alpine plants may benefit from this warming-induced microbial re-shuffling.

Distinct Source Water Chemistry Shapes Contrasting Concentration-Discharge Patterns - J. Kaye; Wei Zhi; Langlang Li; Carl I. Steefel; W. S. Brown; Wenming Dong; Kenneth Hurst Williams (Water Resources Research, 2019)
AbstractUnderstanding concentration‐discharge (C‐Q) relationships are essential for predicting chemical weathering and biogeochemical cycling under changing climate and anthropogenic conditions. Contrasting C‐Q relationships have been observed widely, yet a mechanistic framework that can interpret diverse patterns remains elusive. This work hypothesizes that seemingly disparate C‐Q patterns are driven by switching dominance of end‐member source waters and their chemical contrasts arising from subsurface biogeochemical heterogeneity. We use data from Coal Creek, a high‐elevation mountainous catchment in Colorado, and a recently developed watershed reactive transport model (BioRT‐Flux‐PIHM). Sensitivity analysis and Monte‐Carlo simulations (500 cases) show that reaction kinetics and thermodynamics and distribution of source materials across depths govern the chemistry gradients of shallow soil water and deeper groundwater entering the stream. The alternating dominance of organic‐poor yet geo‐solute‐rich groundwater under dry conditions and organic‐rich yet geo‐solute‐poor soil water during spring melt leads to the flushing pattern of dissolved organic carbon and the dilution pattern of geogenic solutes (e.g., Na, Ca, and Mg). In addition, the extent of concentration contrasts regulates the power law slopes (b) of C‐Q patterns via a general equation. At low ratios of soil water versus groundwater concentrations (Cratio = Csw/Cgw < 0.6), dilution occurs; at high ratios (Cratio > 1.8), flushing arises; chemostasis occurs in between. This equation quantitatively interpretsbvalues of 11 solutes (dissolved organic carbon, dissolved P, NO3−, K, Si, Ca, Mg, Na, Al, Mn, and Fe) from three catchments (Coal Creek, Shale Hills, and Plynlimon) of differing climate, geologic, and land cover conditions. This indicates potentially broad regulation of subsurface biogeochemical heterogeneity in determining C‐Q patterns and wide applications of this equation in quantifyingbvalues, which can have broad implications for predicting chemical weathering and biogeochemical transformation at the watershed scale.

Feeding Preference and Growth Effects for Three Trichoptera Species - D. Hughes (2019)
Detritivores diets are very limited in key nutrients such as phosphorus, nitrogen, and fatty acids. This study looked at how detritivores caddisflies selected food based on nutrient quality. We set up controlled experiments to examine food preference and how that might affect overall growth. Our study found that there is the possibility for preference among different food types and that it could influence growth, but nothing has been confirmed. This study help us understand what types of nutrients were available in these aquatic systems.

Ecological role of Limnephilus abbreviates in detritus dynamics - C. Leitz (2019)
Caddisflies are the dominant detritivores in ponds and wetlands in many high elevation freshwaters. By processing detritus, caddisflies mobilize nutrients and energy that are not used by primary consumers which can play an important role in secondary production and nutrient cycling. Thus, caddisflies are significant for these oligotrophic ecosystems because they are often oligotrophic and therefore limited by nutrients. Previous studies have shown detritus processing by caddisflies stimulates algal growth. Historical data shows that certain species of caddisflies are shifting their range to higher elevations due to increasing temperatures. Past experiments at the Rocky Mountain Biological Laboratory have quantified caddisfly diet, detritus breakdown rates, and influences on algal growth, and other measures for several species of caddisfly in this guild. However, data is missing for several species of caddisflies, including those recently expanding their range upslope. I used a microcosms experiment with Limnephilus abbreviatus, Limnephilus externus, and Anabolia bimaculata caddisflies to measure their contribution to detritus breakdown and algal dynamics. Compared to L. externus, I predicted that L. abbreviatus would have a lower detrital breakdown rate and Anabolia bimaculata would have a higher detrital breakdown rate; and patterns in chlorophyll-a concentration would match these detritus trends. Our results support both predictions for L. abbreviatus however while we found that and that A. bimaculata had a slightly lower detrital breakdown rate than L. externus, their contribution to chlorophyll-a growth was greater. Moving forward, we will be able to use this data to create models that simulate real world conditions to anticipate how caddisflies range shifts affect ecosystem functions.

Late Quaternary vertebrates from the Upper Gunnison Basin, Colorado, and small-mammal community resilience to climate change since the last glacial maximum - Steven D. Emslie; David J. Meltzer (Quaternary Research, 2019)
AbstractThe Upper Gunnison Basin (UGB), Colorado, is a montane region characterized by unusual physiography and topographic isolation. Excavations of three caves in the UGB provide one of the most diverse records of high-elevation late Quaternary vertebrates in North America. The localities, Haystack Cave (2450 m above sea level [m asl]), Cement Creek Cave (2860 m asl), and Signature Cave (3055 m asl), together provide a near-continuous record of vertebrate communities that extends from before the last glacial maximum to the present. These communities largely represent a sagebrush (Artemisiaspp.) steppe-tundra environment that prevailed throughout the UGB in the late Pleistocene. At least five taxa of extinct large mammals disappear from the UGB by the Early Holocene; one small mammal (the short-faced skunkBrachyprotomacf.B.brevimala) also became extinct. The fossil record further indicates that only four small extant mammals (Sorex preblei,Dicrostonyxsp.,Lemmiscus curtatus, andUrocitellus elegans) were extirpated from the UGB by the Early Holocene, in part because of community restructuring and loss of open habitats with expansion of forests to higher elevations. An analysis of taxonomic richness and evenness at Cement Creek Cave indicates high resilience in the small mammal community despite major climate shifts over the past 40,000+ yr.

The Effect of Predation on Ant-aphid Mutualism in Ligusticum porteri - E. Cruz (2019)
Predation and mutualism take up a large part of interactions within communities. These multi-trophic level interactions affect the makeup of the community. We explored how predation impacts the strength of mutualism between ants and aphids on the plant Ligusticum porteri. It has been a base assumption that ants mediate the effect of predation on aphids. We manipulated half of the plants by adding lygus bugs and measured ant density of each site. Through this study, it was discovered the presence of predators broke down the mutualism and disrupted it from forming (P < 0.0056). Ant density had no correlation to the efficiency of the mutualism forming or the strength of it (P = 0.360). Larger aphid colonies did attract more ants, and the larger the number of ants resulted in greater services for the aphids (P < 0.0056). Higher ant abundance resulted in a greater growth rate for aphid colonies. The predation impacts the mutualism potentially affecting aphid, ant and lygus abundance, as well as revealing how ants mediate the effect of predation.

Effects of Climate Change on Birds - David W. Inouye (2019)

Investigating the relationship between plant morphology, density, and herbivory of Thlaspi - B. Laake (2019)
The mustard family Brassicaceae includes many crop species, model plant systems, and invasive species. Many of these species produce a class of secondary defense to deter herbivory with a class of chemicals called glucosinolates (Carlsson et. al, 2009; Keeler & Chew, 2008). Thlaspi arvense is a non-native member of the Brassicaceae family that produces these chemicals, yet it remains a target for herbivory. Studying the interaction of both T. arvense and herbivores assists in understanding the factors of what influences a continued arms race of defense and attack (Rodman and Chew, 1980; Lee et. al, 2009). We will investigate how these two factors react to a change of density and an elevational gradient by measuring herbivory at similar phenological stages in a common garden in the Gothic townsite and in randomized field plots at sites of varying elevation. By manipulating density and seed source in the common garden, environmental factors are stabilized, and herbivory selection factors will become more prominent. We expect to find less herbivory per plant in denser populations and more herbivory in plants with seed sources from higher elevation will experience less herbivory. Intro:

The effect of nutrient availability on floral display and pollinator interactions - N. Fresco (2019)
Management and restoration are important in helping the ecosystem recover back to an original form. Native plant species and pollinators are a highlight of ecological restoration. Nitrogen is a nutrient source that most plants use to thrive to grow bigger. In high alpine communities, the soil is nitrogen poor and if given treatment can help make native plant communities grow back. We tested whether adding nitrogen affected floral display and pollination. In this study, the field site location is an area that had been stripped away to bare land to build the billy barr community center in Gothic, Colorado. After the billy barr community was successfully built, the land was bare, so there was a restoration project of bringing back native plants in 2017. There are 24 plots were given treatment of either a control, nitrogen in the form of ammonium nitrate, and carbon in the form of sugar. The experiment focused itself in the summer of 2019, to measure floral display and pollinator interactions with the treatments of the plots. The study consisted of counting how many open flowers were open in the plot, the three native plant species that we focused on was Potentilla pulcherrima, Polemonium foliosissmum, and Linum lewisii (flax). I observed pollinators at each plot; where once a pollinator landed on the plant species that was either Potentilla pulcherrima, Polemonium foliosissmum, or Linum lewisii (flax), it would then be noted and what kind of pollinator. The pollinators that we focused on was the native pollinator species in Gothic, Colorado which consisted of Bombus spp, Osmia, Sweat bees, Mining bees, Bee flies, True fly, Pieridae, Lycaenidae, Swallowtails western tiger, Papilio gothica, Checker spots and Speyeria. These observations took place several times, to have data to test our hypothesis. We found that nitrogen has no effect on floral display and on pollinator visitation. We did find that having a bigger floral display increased pollinator visitation. A recommendation for restoration is to have large flower patches to increase pollinator visitations.

Low to Mid Elevational Resurvey of Bumble bee Distributions in Response to Climate Change - J. Hsu (2019)
In 1974, Graham Pyke conducted a study that examined Bombus spp. distributions along five transects around the Rocky Mountain Biological Laboratory area in Crested Butte, CO. The study was repeated in 2007 and within the intervening 33-year period, it showed that certain species of bumble bees had shifted higher in elevation due to climate change. The study has been repeated every five to seven years since 2007 with the most recent re-survey carried out in 2014. These studies are intended to use bumble bees as an ideal indicator of climate change due to their rapid life cycle. In 2019, I repeated the study using only low to mid-elevation sites to determine whether there was an increase or decrease in relative abundance compared to 2014. Data was collected by capturing bumble bees, identifying them in the field, and also taking photos of bumble bees in a clear cylindrical PVC tube to confirm field identifications. I also recorded the flower species the bumble bees were collected off of. Floral surveys were also conducted to assess whether floral distributions affected bumble bee distributions. We found a general increase in low-elevation species and a general decrease in high-elevation species over the elevation range that I studied, with the exception of one species. Comparison of floral phenology over a short period of time suggested that some plants were present in 2014 that were not present in 2019, which may be attributed to climate change or successional changes in the sites over time. The findings indicated that bumble bee species composition at each site has slightly shifted, but a larger sampling over the entire elevation range will help indicate whether these slight shifts are due to climate change or other unmeasured factors.

Effects of avalanches on rodent populations - G. Sandoval (2019)
Ecologists are interested in studying the factors that affect the abundance of a species. Disturbances, such as avalanches, could affect the populations of small mammals. Live trapping has been a traditional method to study abundances of small mammals; however, it has some downsides. A new, non-invasive method of measuring small mammal abundance was tested in a study last year (2018), and proved to be a good indicator of abundance, but not identification of specific species. This new method is using hair tube traps. This year (2019), these hair tube traps were used to measure the effect of avalanches on small mammal populations. The results showed that avalanches had an effect on abundance at three of the four sites, and that these sites showed a recovery at both the avalanche and non-avalanche sites over the summer.

Return flows from beaver ponds enhance floodplain-to-river metals exchange in alluvial mountain catchments - F. D. Day-Lewis; J. W. Lane; Martin Briggs; Chen Wang; Wenming Dong; Kenneth Hurst Williams (Science of the Total Environment, 2019)
River to floodplain hydrologic connectivity is strongly enhanced by beaver- (Castor canadensis) engineered channel water diversions. The hydroecological impacts are wide ranging and generally positive, however, the hydrogeochemical characteristics of beaver-induced flowpaths have not been thoroughly examined. Using a suite of complementary ground- and drone-based heat tracing and remote sensing methodology we characterized the physical template of beaver-induced floodplain exchange for two alluvial mountain streams near Crested Butte, Colorado, USA. A flowpath-oriented perspective to water quality sampling allowed characterization of the chemical evolution of channel water diverted through floodplain beaver ponds and ultimately back to the channel in 'beaver pond return flows'. Subsurface return flow seepages were universally suboxic, while ponds and surface return flows showed a range of oxygen concentration due to in-situ photosynthesis and atmospheric mixing. Median concentrations of reduced metals: manganese (Mn), iron (Fe), aluminum (Al), and arsenic (As) were substantially higher along beaver-induced flowpaths than in geologically controlled seepages and upstream main channel locations. The areal footprint of reduced return seepage flowpaths were imaged with surface electromagnetic methods, indicating extensive zones of high-conductivity shallow groundwater flowing back toward the main channels and emerging at relatively warm bank seepage zones observed with infrared. Multiple-depth redox dynamics within one focused seepage zone showed coupled variation over time, likely driven by observed changes in seepage rate that may be controlled by pond stage. High-resolution times series of dissolved Mn and Fe collected downstream of the beaver-impacted reaches demonstrated seasonal dynamics in mixed river metal concentrations. Al time series concentrations showed proportional change to Fe at the smaller stream location, indicating chemically reduced flowpaths were sourcing Al to the channel. Overall our results indicated beaver-induced floodplain exchanges create important, and perhaps dominant, transport pathways for floodplain metals by expanding chemically-reduced zones paired with strong advective exchange.

A meta-analysis of 1,119 manipulative experiments on terrestrial carbon-cycling responses to global change - Z. Yang; Yufei Liu; Dongdong Wang; S. Niu; S. Fatichi; R. J. Norby; D. Guo; S. Piao; P. Ciais; Y. Y. Wang; Shiqiang Wan; Jian Song; et al. (Nature Ecology & Evolutiion, 2019)
There is an urgent need to explore the interactions among multiple global change drivers in underrepresented regions such as semi-arid ecosystems, forests in the tropics and subtropics, and Arctic tundra when forecasting future terrestrial carbon-climate feedback.

Evaluation of genetic change from translocation among Gunnison Sage-Grouse (Centrocercus minimus) populations (The Condor, 2019)
AbstractMaintenance of genetic diversity is important for conserving species, especially those with fragmented habitats or ranges. In the absence of natural dispersal, translocation can be used to achieve this goal, although the success of translocation can be difficult to measure. Here we evaluate genetic change following translocation in Gunnison Sage-Grouse (Centrocercus minimus), a species reduced to 7 discrete populations with low levels of gene flow and high levels of genetic differentiation. Between 2000 and 2014, 306 birds from the largest and most genetically diverse population (Gunnison Basin) were translocated to 5 much smaller satellite populations to augment local population size and increase genetic diversity. Although the magnitude of the effect varied by population, we found evidence of increased genetic variation, decreased genetic differentiation from Gunnison Basin, and reproduction between translocated individuals and resident birds. These results suggest that translocations are impacting satellite populations, with current data providing a new baseline for genetic diversity among populations of this imperiled species.

Stable isotope compositions of precipitation from Gunnison, Colorado 2007–2016: implications for the climatology of a high-elevation valley - Suzanne B. Marchetti; David W. Marchetti (Heliyon, 2019)
Stable isotope ratios of precipitation are useful tracers of climatic and hydrological processes. To better understand the isotope hydro-climatology of a high-elevation Rocky Mountain valley we collected meteoric water samples from Gunnison, Colorado, USA and determined stable isotope values for 239 individual precipitation events over a nine year period. Annual precipitation in Gunnison is moderately bi-modal with significant winter snowfall and convective summer thunderstorms associated with the North American Monsoon. Stable isotope values of precipitation span a large range, with summer rains as high as δ2H = +19‰ and δ18O = +4.8‰ (relative to V-SMOW) and winter snowfall as low as δ2H = -286‰ and δ18O = -36.7‰. These data define a local meteoric water line for Gunnison of δ2H = 7.2 δ18O - 4.2. Monthly meteoric water lines have slopes similar to the Global Meteoric Water Line (∼8) for winter months and more evaporated slopes (∼6) during the summer. Monthly mean temperature most strongly controls the monthly isotopic composition of precipitation (m = 0.61-0.64 ‰/°C); the slope of the isotope/temperature relationship is steeper in summer than winter.

The Risk of Curtailment under the Colorado River Compact - Jacob A. Fleck; Anne J. Castle (SSRN Electronic Journal, 2019)
Water supply in the Colorado River could drop so far in the next decade that the ability of the Upper Colorado River Basin states – Colorado, Utah, Wyoming, and New Mexico – to meet their legal obligations to downstream users in Nevada, Arizona, California, and Mexico would be in grave jeopardy. Legal institutions designed nearly a century ago are inadequate to address the significant risk of shortfall combined with uncertainty about whose water supplies would be cut, and by how much. This report indicates that declines in the Colorado River’s flow could force water curtailments in coming decades, posing a credible risk to Colorado communities and requiring serious consideration of insurance protection like demand management.

Fungal colonization of plant roots is resistant to nitrogen addition and resilient to dominant species losses - Quentin D Read; Jeremiah A Henning; Aimee T Classen; Nathan J. Sanders (Ecosphere, 2019)
Abstract Global change drivers, such as nitrogen (N) deposition and non‐random species extinctions, may shift interactions among aboveground and belowground communities. However, tightly coupled interactions between aboveground and belowground organisms may buffer ecosystems to global change. Here, we test how four years of organic and inorganic N addition and removal of a dominant plant species, Festuca thurberi , independently and interactively influences fungal colonization patterns and performance in a co‐dominant plant species, Helianthella quinquenervis . Surprisingly, we found N addition and Festuca removal had no measurable effects on the colonization of arbuscular mycorrhizal fungi (AMF) and dark septate endophyte ( DSE ) or the performance of Helianthella seedlings grown with field‐collected inoculum in a companion greenhouse experiment. However, the proximity of Helianthella to Festuca predicted fungal colonization: DSE colonization decreased by 1% for each cm of distance Helianthella was from Festuca , although the differences in fungal inoculum potential had no effect on Helianthella seedling survival or biomass. Our results suggest that plant–fungal interactions can be resistant to N addition and resilient to the loss of dominant plant species. Additionally, our results suggest that soil legacies, mediated through surviving symbiont communities or changes in soil properties, can shape ecosystem resistance and resilience to disturbance and perturbations.

Altitudinal gradients fail to predict fungal symbiont responses to warming - D. L. Taylor; Melanie R Kazenel; Jennifer A. Rudgers; Stephanie N. Kivlin; Joshua S. Lynn (Ecology, 2019)
AbstractClimate change is shifting altitudinal species ranges, with potential to disrupt species interactions. Altitudinal gradient studies and warming experiments can both increase understanding of climate effects on species interactions, but few studies have used both together to improve predictions. We examined whether plant–fungal symbioses responded similarly to altitude and 23 yr of experimental warming. Root‐ and leaf‐associated fungi, which can mediate plants’ climate sensitivity, responded divergently to elevation vs. warming. Fungal colonization, diversity, and composition varied with altitude, but climate variables were generally weak predictors; other factors such as host plant identity, plant community composition, or edaphic variables likely drive fungal altitudinal distributions. Manipulated warming altered fungal colonization, but not composition or diversity. Leaf symbionts were more sensitive to climate and experimental warming than root symbionts. Altitudinal patterns and responses to warming differed among host plant species and fungal groups, indicating that predicting climate effects on symbioses will require tracking both host and symbiont identities. Combining experimental and observational methods can yield valuable insight into how climate change may alter plant–symbiont interactions, but our results indicate that altitude does not always serve as an adequate proxy for warming effects on fungal symbionts of plants.

Elevational cline in herbivore abundance driven by a monotonic increase in trophic level sensitivity to aridity - Matthew J. Hecking; Cole T. Symanski; Annika S. Nelson; Kailen A. Mooney (Journal of Animal Ecology, 2019)
The abiotic environment drives species abundances and distributions both directly and indirectly through effects on multi-trophic species interactions. However, few studies have documented the individual and combined consequences of these direct and indirect effects. We studied an ant-tended aphid along an elevational gradient, where lower elevations were more arid. Hypotheses of stronger species interactions at lower elevations and a greater sensitivity of higher trophic levels to climate led us to predict increased top-down control of aphids by natural enemies (third trophic level) but even stronger protection from mutualist ants (fourth trophic level) with increasing aridity. As a result, we predicted that mutualism strength and aphid abundance would increase with aridity. We documented patterns of aphid abundance and tested for both the direct and multi-trophic indirect effects of aridity on aphid performance. To do so, we used both observational and manipulative methods across two years in replicate high- and low-elevation valleys, where summer temperatures decreased by 3.7°C and precipitation increased by 27 mm/mo from low to high elevations. Aphid colonies were 75% larger in the most (vs. least) arid sites, and this was best explained by changes in interactions with predators and ants. Aphids were unaffected by the direct effects of the abiotic environment or its indirect effects via host plant quality. In contrast, natural enemy effects increased with aridity; under ant exclusion, natural enemies had no effect on aphids in the least arid sites but depressed colony growth by 252% in the most arid sites. Ant activity also increased with aridity, with ants discovering more aphid colonies and experimental baits and allocating more foragers per aphid, although there was no effect of aridity on ant abundance or community composition. Correspondingly, the mutualist services provided by ants increased with aridity; ants provided no benefits to aphids in the least arid sites but doubled colony growth in the most arid sites. In summary, an elevational cline in herbivore abundance was driven by a monotonic increase in trophic-level sensitivity to aridity. These findings illustrate that predicting species responses to climate change will require a multi-trophic perspective.

Pre- and post-ingestive defenses affect larval feeding on a lethal invasive host plant - L. M. Fisher; Rachel A Steward; Carol L. Boggs (Entomologia Experimentalis et Applicata, 2019)
Abstract Evolutionary traps arise when organisms use novel, low‐quality or even lethal resources based on previously reliable cues. Persistence of such maladaptive interactions depends not only on how individuals locate important resources, such as host plants, but also the mechanisms underlying poor performance. Pieris macdunnoughii (Remington) (Lepidoptera: Pieridae) lays eggs on a non‐native mustard, Thlaspi arvense (L.) (Brassicaceae), which is lethal to the larvae. We first tested whether larval feeding behavior was affected before (pre‐) ingestion or following (post‐) ingestion of leaf material, indicating activity of feeding deterrents, toxins, or both in this evolutionary trap. Neonates were less likely to start feeding and eventually fed more slowly on T. arvense than on the native host plant Cardamine cordifolia (Gray) (Brassicaceae) in both laboratory and field. Starvation was a primary cause of mortality, indicating the role of a feeding deterrent. Feeding did not differ between larvae from invaded and uninvaded population. Second, T. arvense defensive chemistry is dominated by the glucosinolate sinigrin (allyl or 2‐propenyl glucosinolate). Adding sinigrin to the leaves of T. arvense and native hosts C. cordifolia and Descurainia incana (Bernhardi ex Fischer & Meyer) (Brassicaceae) delayed the onset of feeding, caused larvae to feed more slowly, and decreased survival on the native hosts. This evolutionary trap may not be driven by a novel deterrent, but rather by a change in the concentration of a deterrent found in native hosts. Many insects have adapted to evolutionary traps posed by invasive plants, incorporating the new plant into their diets. Thlaspi arvense remains lethal to P. macdunnoughii , and pre‐ingestive deterrents such as excess sinigrin may contribute to persistent maladaptation.

Parasitism modifies the direct effects of warming on a hemiparasite and its host - Paul D. Nabity; L. Agnew; Nicole E. Rafferty (PLOS ONE, 2019)
Climate change is affecting interactions among species, including host-parasite interactions. The effects of warming are of particular interest for interactions in which parasite and host physiology are intertwined, such as those between parasitic plants and their hosts. However, little is known about how warming will affect plant parasitic interactions, hindering our ability to predict how host and parasite species will respond to climate change. Here, we test how warming affects aboveground and belowground biomass of a hemiparasitic species (Castilleja sulphurea) and its host (Bouteloua gracilis), asking whether the effects of warming depend on the interaction between these species. We also measured how warming affected the number of haustorial connections between parasite and host. We grew each species alone and together under ambient and warmed conditions. Hosts produced more belowground biomass under warming. However, host biomass was reduced when plants were grown with a hemiparasite. Thus, parasitism negated the benefit of warming on belowground growth of the host. Host resource allocation to roots versus shoots also changed in response to both interaction with the parasite and warming, with hosts producing more root biomass relative to shoot biomass when grown with a parasite and when warmed. As expected, hemiparasite biomass was greater when grown with a host. Warmed parasites had lower root:shoot ratios but only when grown with a host. Under elevated temperatures, hemiparasite aboveground biomass was marginally greater, and plants produced significantly more haustoria. These findings indicate that warming can influence biomass production, both by modifying the interaction between host plants and hemiparasites and by affecting the growth of each species directly. To predict how species will be affected, it is important to understand not only the direct effects of warming but also the indirect effects that are mediated by species interactions. Ultimately, understanding how climate change will affect species interactions is key to understanding how it will affect individual species.

How vulnerable are pollen-specialist solitary bees to temperature-mediated shifts in the timing of food availability? - G. Gauthier (2019)
Rising temperatures are advancing the seasonal timing of flowering and pollinator activity in

Assessment of Spatiotemporal Variability of Evapotranspiration and Its Governing Factors in a Mountainous Watershed - J. Rungee; Anh Phuong Tran; Boris Faybishenko; Baptiste Dafflon; S. S. Hubbard (Water, 2019)
Evapotranspiration (ET) is a key component of the water balance, which influences hydrometeorology, water resources, carbon and other biogeochemical cycles, and ecosystem diversity. This study aims to investigate the spatio-temporal variations of ET at the East River watershed in Colorado and analyze the factors that control these variations. ET was acquired using the community land model (CLM) simulations and was compared with the values estimated using Fu’s equation and a watershed-scale water balance equation. The simulation results showed that 55% of annual precipitation in the East River is lost to ET, in which 75% of the ET comes from the summer months (May to September). We also found that the contribution of transpiration to the total ET was ~50%, which is much larger than that of soil evaporation (32%) and canopy evaporation (18%). Spatial analysis indicated that the ET is greater at elevations of 2950–3200 m and lower along the river valley (<2750 m) and at the high elevations (>3900 m). A correlation analysis of factors affecting ET showed that the land elevation, air temperature, and vegetation are closely correlated and together they govern the ET spatial variability. The results also suggested that ET in areas with more finely textured soil is slightly larger than regions with coarse-texture soil. This study presents a promising approach to the assessment of ET with a high spatiotemporal resolution over watershed scales and investigates factors controlling ET spatiotemporal variations.

Intraspecific flower color variation along elevation gradients - Arthur E. Smith (2019)

Phenotypic plasticity of floral volatiles in response to increasing drought stress - Paula Sosenski; Robert A. Raguso; Diane R. Campbell (American Journal of Botany, 2019)

The effect of 10 years of repeat lethal sampling on wild bee abundance - H. T. Benkoski (2019)
Insect pollinators serve vital roles in natural and agricultural systems. There is a lack of long-term data on wild bee populations in North America, so standardized sampling protocols have been developed to address this need. The purpose of this study was to determine the effect of 10 years of long-term, repeated lethal sampling through the use of aerial netting and pan traps on wild bee abundance. Several single-sample sites were sampled and compared to phenologically similar sites that had been repeatedly sampled for a decade. In this paper, we focus on the bumble bees only. We predicted to find no effect of repeated sampling on bumble bee abundance or diversity because they are not lethally sampled but, rather, identified in the field and released. We found no significant difference between the catch rate and species richness for bumble bees caught among single-sample and their paired repeated-sample sites. This suggests that the paired sites are suitably comparable, and allows us to move forward in the analysis of the lethally sampled, solitary bees’ catch rate and species richness among the single-sample and repeated-sample sites.

Spectacle in the meadows - David W. Inouye (Gunnison County Times, 2019)

Social security: less socially connected marmots produce noisier alarm calls - H. Fuong; Daniel T. Blumstein (Animal Behaviour, 2019)
The nonlinearity and fear hypothesis predicts that the structure of alarm vocalizations will be influenced by the signaller's internal state. Specifically, stressed or otherwise more aroused individuals will produce alarm calls that are relatively more nonlinear (i.e. they sound noisier). The position of an individual in a social network can influence an individual's sense of security. More centrally located individuals may feel more secure and thus we might expect that they would produce noisier calls. Building on previous research about the influence of social relationships on an individual's sense of security, we asked whether social network position explained variation in the noisiness (quantified as Wiener entropy) and goodness of pitch of alarm calls produced by trapped yellow-bellied marmots, Marmota flaviventer. More socially isolated individuals, characterized by lower instrength, produced alarm calls with higher entropy and higher goodness of pitch. These isolated individuals may be more aroused because they have fewer social partners to depend on when presented with a predatory threat; therefore, they produce both noisy and potentially louder calls. Additionally, individuals with higher outcloseness produced calls with higher goodness of pitch, which may be indicative of their ability to better inform neighbours of impending threats. Overall, this study further illustrates how an individual's social network position influences the structure of its alarm calls, which could reflect how individuals perceive their current safety levels.

No evidence that gut microbiota impose a net cost on their butterfly host - Kabir Peay; A. Ravencraft; Nicole Kish; Carol L. Boggs (Molecular Ecology, 2019)
Gut microbes are believed to play a critical role in most animal life, yet fitness effects and cost-benefit trade-offs incurred by the host are poorly understood. Unlike most hosts studied to date, butterflies largely acquire their nutrients from larval feeding, leaving relatively little opportunity for nutritive contributions by the adult's microbiota. This provides an opportunity to measure whether hosting gut microbiota comes at a net nutritional price. Because host and bacteria may compete for sugars, we hypothesized that gut flora would be nutritionally neutral to adult butterflies with plentiful food, but detrimental to semistarved hosts, especially when at high density. We held field-caught adult Speyeria mormonia under abundant or restricted food conditions. Because antibiotic treatments did not generate consistent variation in their gut microbiota, we used interindividual variability in bacterial loads and operational taxonomic unit abundances to examine correlations between host fitness and the abdominal microbiota present upon natural death. We detected strikingly few relationships between microbial flora and host fitness. Neither total bacterial load nor the abundances of dominant bacterial taxa were related to butterfly fecundity, egg mass or egg chemical content. Increased abundance of a Commensalibacter species did correlate with longer host life span, while increased abundance of a Rhodococcus species correlated with shorter life span. Contrary to our expectations, these relationships were unchanged by food availability to the host and were unrelated to reproductive output. Our results suggest the butterfly microbiota comprises parasitic, commensal and beneficial taxa that together do not impose a net reproductive cost, even under caloric stress.

Observing pollinator trait variation in relation to niche breadth in seasons of high and low precipitation - B. E. Davis (2019)
Interactions between plants and pollinators are complex and a change to one can cause a significant impact on the other. Environmental perturbations like drought can alter plant- pollinator systems, changing the relative abundance of flower species, shifting species distribution, and decreasing floral resources. As a result of these drought-induced changes, pollinators, particularly insect pollinators, may be forced to change their foraging behavior. Pollinators’ foraging behavior is greatly defined by their niche breadth, which is the set of flower species that they can and will visit. A niche breadth is influenced by multiple factors such as the phenology of flowers, geography, and both the morphology of flowers and pollinators. Pollination events are more likely to occur if the morphological traits of the pollinator and the flower “match” in such a way as to make the interaction most efficient and beneficial for both partners: the pollinator needs to be able to reach nectar and the plant must be able to deposit its pollen on the pollinator for transport to another flower. In this way trait matching helps to define pollinator niche breadths. In this project I examined the impact of a drought in 2018 on the foraging patterns and niche breadth of pollinator species in the area around Gothic, Colorado. I predicted that because of the drought and resulting decrease or shift in floral resources, flower abundance, and flower species distribution, pollinating insect species will be forced to alter their foraging behavior and widen their niche breadth. As a result of this increase in generalist foraging behavior, bee traits and floral traits would likely match less frequently during the drought year. I found this hypothesis to be mostly rejected; trait matching was essentially nonexistent in the compared traits in the drought year and the next non-drought year. Floral abundance did decrease during the drought, but floral species richness did not significantly decrease. There was no clear decrease in pollinator abundance during the drought, however there was a decrease in pollinator abundance in the following year. This shows that a pollinator group’s niche breadth is highly variable and likely impacted by multiple factors including, but not limited by, floral abundance, floral species richness, abundance of other pollinators, and the quantity and quality of floral resources.

Predator and prey species have opposing responses to recreational trail use - A. Escamilla (2019)
While many ecological studies have investigated the impacts of recreation and trails on wildlife, we lack an understanding of how wildlife respond to recreational trails that exhibit seasonally dynamic levels of human activity. We used camera traps to assess changes in the presence of mammals along a recreational trail before and during the summer tourism season in Crested Butte, CO. We used linear mixed-effects regression models to explain variation in the ungulate and carnivore detection rates as a function of whether the cameras were on or off a trail, on an established versus proposed trail, and how these interacted with the presence of dogs, humans, and for ungulates, carnivores. We controlled for the potentially confounding effects of distance from trailhead and controlled for detectability by quantifying the proportion of each camera’s detection area that was covered with trees using ArcMap. We found that deer and elk detection rates were higher in July and in the current trail section, suggesting that prey species prefer areas with high levels of human activity. Carnivore species detection rates were higher in the proposed trail section in June, suggesting that predator species prefer areas with low levels of human activity. Overall, we found that both prey and predator species show rapid, but opposing, behavioral changes in response to season and recreational trail use.

Tracking diverse minerals, hungry organisms, and dangerous contaminants using reactive transport models (Elements, 2019)

The Direct and Interactive Effects of Warming and Species Interaction on Plant Functional Traits - K. Rand (2019)
Global climate change is a threat that continues to affect nearly every ecosystem on the planet through warmer temperatures, changes in precipitation patterns, and many other manifestations of a warmer world. Warming directly and indirectly affects plants and ecosystem functioning. In the natural world, both the direct and indirect effects of warming impact plant communities and the ecosystem functions simultaneously. Here, we conducted an experiment to determine how the direct and indirect effects of warming impacts plant functional traits in an alpine ecosystem. We leveraged an existing warming experiment in the Upper Gunnison Valley Basin in Colorado, USA. The ongoing 6-year study elevates plot temperatures using open-top warming chambers and manipulates species composition by removing the dominant plant species at a high and low elevation to evaluate the direct and indirect effects of warming on ecosystem structure and function. We sampled plant species from within the plots to answer a series of interrelated questions focused on how shifts in warming and species interactions alters plant functional traits: (1) How does warming directly alter plant functional traits? (2) How does removing the dominant species alter plant functional traits by shifting species interactions? (3) Will warming and species removal interact synergistically to alter plant traits? We hypothesized that: (1) Warming will shift the individual and community-wide traits to be more conservative by exacerbating water-stress in a moisture-limited environment. (2) Removing the dominant species will shift the plant community to be more acquisitive as the remaining plants are released from competitive pressure. (3) Warming and species removal will have counteractive effects on plant functional traits, possibly neutralizing the simulated effects of climate change on plant communities when both treatments occur simultaneously. Our results confirmed that warming and species removal have opposing effects on community shifts, though not in the direction that was expected. By comparing trait values within a species across the warming and removal treatments, we did not see overall shifts in most traits. The shifts in communities are therefore driven by shifts in the relative abundance of species as climate change selects for plant species that are best adapted to warmer environments in the absence of the dominant species, creating winners and losers in the plant community. From our results, it is evident that direct and indirect effects of climate change counteract each other rather than amplify each other. Functional traits of plants remain an effective lens through which we can observe the pathways through which climate change drives shifts in ecosystem structure and function.

Impacts of the invasive species Linaria vulgaris on soil ecology and native plant biodiversity - F. Shirley (2019)
Invasive species are a major threat to biodiversity. Invasive plant species can alter ecosystems by outcompeting natives, lowering biodiversity, and change soil ecology. Additionally, invasive species can be costly to manage. Linaria vulgaris, a non-native noxious weed from Europe and Asia, was used as a study organism to better understand how invasive plant species impact biodiversity and soil ecology. I hypothesized that Linaria vulgaris would lower native plant biodiversity and increase litter and total nitrogen levels in invaded areas. However, there was no significant difference found between plots with L. vulgaris present or absent or with plots where L. vulgaris has been experimentally pulled for 19 years. Additionally, I hypothesized that the soil ecology was negatively affecting L. vulgaris growth. However, a potted-plant experiment found no significant difference in the growth of L. vulgaris between soils where it was locally abundant vs. declining. Taken together, these results suggest that L. vulgaris may surpass its own carrying capacity and decline its own population, allowing native plant species to rebound in abundance in the presence of L. vulgaris.

Trap behavior of Zonotrichia leucophrys oriantha at different elevations in the West Elk Mountains, Colorado - E. Wieser (2019)
High-alpine ecosystems are particularly vulnerable to climate change. Thus, many ecosystem patterns are shifting due to warming temperatures, extreme weather events, and seasonal changes. This becomes an issue for birds that breed and live in high-elevation environments, as they may not be able to co-adapt quick enough to rapid shifts in mountain conditions and habitat. Zonotrichia leucophrys oriantha or the Mountain White-Crowned Sparrow (henceforth called: oriantha) is a native, migratory species that resides in Gunnison County, CO, USA. Oriantha can serve as a model species because it lives and breeds across an elevational range, allowing for life-history differences in the population to be observed. Our hypothesis states that if there are variations in life-history traits along an elevational gradient, than trap-behavior will also show variation. Within this study, our aim was to determine whether there were differences in oriantha behavior across elevation by gauging the level of trap-activity at different elevations. We predicted such differences would exist between elevations. We tested for variables including sex, fat, tarsus length, recapture count, and whether the bird was previously banded. The most significant effects on the activity index of trapped birds were elevation and recapture counts, while sex, fat, tarsus length, and previously banded showed no significant effects. Although stress-induced energetics may account for different trap-activity levels, a more thorough and direct examination needs to be conducted in order to explain the causal mechanisms of such differences and how elevation plays a role in trap-behavior.

Seasonal manganese transport in the hyporheic zone of a snowmelt-dominated river (East River, Colorado) - S. R. Bryant (2019)
Manganese (Mn) plays a critical role in river water quality since Mn-oxides serve as

Pollinator mediated reproductive consequences of altered co-flowering under climate change depend on abiotic context - M. Faust (2019)
Pollinator mediated reproductive consequences of altered co-flowering under climate change depend on abiotic context

The persistent maladaptation of Pieris macdunnoughii: Constraints on adaptation to an evolutionary trap - Rachel A Steward (2019)
Evolutionary traps arise when organisms use novel, low-quality or even lethal resources based on previously reliable cues. Persistence of such maladaptive interactions depends not only on how individuals locate important resources, such as host plants, but also the mechanisms underlying poor performance. Pieris macdunnoughii (Remington) (Lepidoptera: Pieridae) lays eggs on a non-native mustard, Thlaspi arvense (L.) (Brassicaceae), which is lethal to its larvae. However, in the 150 years since T. arvense invaded this butterfly continues to recognize and oviposit on the invasive mustard. I evaluated two possible constraints on the evolution of decreased preference within an invaded population. First, an evolutionary response to selection may be constrained by low heritable genetic variation for preference. Second, evolutionary traps are expected to persist when overlapping cue sets (cue similarity) link decreased preference for the novel, unsuitable plant with decreased preference for the historical, high-quality resources. I determined that while preference for the nonnative host over the native host is heritable, sex-linked, and varies considerably in the population, it is unlikely that this preference is correlated with preference for native hosts with similar defensive chemical profiles. Thus, neither a lack of heritable genetic variation nor an increased risk of excluding good host plants when avoiding T. arvense are likely to be constraining escape from this evolutionary trap. Instead, our results suggest behavioral v plasticity may buffer populations from innate preference for the lethal host. Finally, I tested the mechanisms underlying poor performance of neonate larvae on the novel host. Larvae were less likely to start eating T. arvense and starvation was a primary cause of mortality, indicating a pre-ingestive feeding deterrent. A primary oviposition stimulant, the glucosinolate sinigrin, increased this deterrent effect and mortality when added to T. arvense and native host plant leaves. Pre-ingestive deterrents, even those familiar to herbivorous insects, may significantly contribute to the persistence of evolutionary traps. vi

Colorado's Joint Review Process: The AMAX Experience - Michael J. Rock (2019)
The Colorado mountains include a mineral belt containing molybdenum, which is only slightly more common than gold. The Henderson Mine, which was built in the mid-1960s, was the largest private sector capital investment ever made in the State of Colorado. The Mount Emmons Mine, which will cost one billion dollars to develop, may again be the largest private sector investment in Colorado. AMAX had an advantage when it came into Gunnison County because it had a good reputation in Colorado from its work on the Henderson Mine and the Experiment in Ecology that was conducted there. The county, Colorado Department of Natural Resources, and the United States Forest Service serve as the lead agencies at these meetings which are also attended by representatives of other cooperating agencies. AMAX therefore asked ROMCOE, Center for Environmental Problem Solving, to organize a tour of several boom town areas in Colorado and Wyoming.

Is there intraspecific variation in synchrony in subalpine flowering species? - A. Turner (2019)

Is the Recent Drought on the Colorado River the New Normal? - Joseph Barsugli; Ben Livneh; Martin Hoerling (Eos, 2019)
Understanding Historical Changes in the Flow of the Colorado River; Boulder, Colorado, 24–25 September 2018

Implications of global climate change on cow parsnip in Colorado: from flowering phenology to multitrophic interactions - Bjostad, Louis; Ode, Paul J.; Seshadri, Arathi; Brittany N. Smith (Digital Collections of Colorado (Colorado State University), 2019)
Plants play a central role in structuring nearly all terrestrial communities and providing ecosystem services. As ectothermic organisms, the synchronization of plant and insect life history events (phenology) are strongly dependent on temperature and precipitation, two of the major components of climate change. Plants can serve as indicator species for how climate change might alter community composition that in turn contributes to ecosystem and landscape stability. I investigated elevation as a proxy for climate change from ten spatially separate Colorado populations of cow parsnip Heracleum maximum Bartram (Apiaceae) in both 2017 and 2018. I studied, plant flowering phenology and plant trait measurements that attributed to plant fitness measures (seed production and weight). Additionally, I investigated floral visitors in association with flowering phenology and how the presence or absence of parsnip webworm Depressaria radiella Goeze (Lepidoptera: Depressariidae) impacted pollinators visiting plants. I found that elevation does not clearly explain phenological differences amongst H. maximum plants in high elevations (>2600m), yet insect diversity decreases as elevation increases. Additionally, D. radiella presence increases plant seed production, and secondary plant umbels compensate for consumed primary umbel flowers and fruit. I also found that male flowers with pollen or female flowers with nectar are not significantly different from each other in regard to insect families that visit them. Lastly, both abiotic conditions and biotic plant-insect interactions may contribute to multitrophic community assemblages under warming temperatures.

Global Climate Change-Induced Mutualism Breakdown Among Legumes and their Soil Synbionts - E. Paulson (2019)

Effect of blood parasites on incubation efficiency of Z. l. oriantha in the Colorado Rocky Mountains - C. McCuen (2019)
Haemoparasites are common in passerines and have known mild to detrimental effects on populations. It is important to understand how these effects influence nest incubation in females, as it could reflect future reproductive success of that species as vectors and transmission increase with climate change. We investigated how incubation temperatures varied in female mountain white-crowned sparrows in the presence and absence of haemoparasites to determine if these parasites are influencing efficiency. There was a trend showing that parasitized females showed more variance in nest temperature, but it was not significant. A larger sample is necessary to draw conclusions from this study.

Pollen and vegetative secondary chemistry of three pollen-rewarding lupines - Daniel Cook; Jacob M. Heiling; Stephen T. Lee; Rebecca E. Irwin (American Journal of Botany, 2019)
Our results are consistent with the hypothesis that, in these pollen-rewarding species, pollen secondary chemistry may reflect the need to attract and reward pollinators more than the need to defend pollen from herbivory.

Streamflow partitioning and transit time distribution in snow-dominated basins as a function of climate - Z. Fang; D. Wilusz; C. Harman; Rina Schumer; Kenneth Hurst Williams (Journal of Hydrology, 2019)
Abstract Snowmelt is the principal control on the timing and magnitude of water flow through mountainous watersheds. The effects of precipitation type and quantity on storage and hydrologic connectivity in mountainous systems were explored by combining the observed stable isotope δ18O in rain, snow, snowmelt, and streamflow with numerically simulated hydrologic boundary fluxes and inverse techniques applied to transient travel time distributions (TTD) using StorAge Selection (SAS) functions. Hydrologic simulations of the East River (ER, 85 km2), a snow-dominated Colorado River headwater basin, for water years 2006–2017 were used to test a diverse set of snow accumulation scenarios. During the snowmelt period, the ER released younger water during high storage periods across seasonal and annual timescales (an “inverse storage effect”). Additionally, more young water was released from storage during wet years than during dry years. However, wet years also appeared to increase hydrologic connectivity, which simultaneously flushed older water from the basin. During years with reduced snowpack, flow paths were inactivated and snowmelt remained in the subsurface to become older water that was potentially reactivated in subsequent wet years. Incremental warming in hydrologic model simulations was used to evaluate TTD sensitivity to precipitation changing from snow to rain. Despite the altered timing of boundary fluxes because of warming, years with basin average precipitation above 3.25 mm d−1 (1200 mm y−1) were resilient to temperature increases up to 10 °C with respect to annual water balance partitioning and streamflow TTD. In contrast, years with less precipitation were sensitive to increased temperatures, showing marked increases in the fraction of inflow lost to evapotranspiration. Younger water was preferentially lost to evapotranspiration, which led to an increase in the mean age of streamflow in drier years.

Litter relocation behavior in two species of ground dwelling squirrels - A. J. Rossi; J. R. Aliperti; Kenneth B. Armitage; D. H. Van Vuren (Ethology, 2019)
Abstract Maternal investment in mammals may take many forms, including spatial relocation of offspring. Litter relocation behavior, in which a female moves her litter to a new location, has been reported for several species of carnivores and rodents but has received little study. We describe litter relocations during long‐term studies of two species of ground‐dwelling squirrels, yellow‐bellied marmots (YBM, Marmota flaviventer ) and golden‐mantled ground squirrels (GMGS, Callospermophilus lateralis ), to determine the distance and frequency of litter relocations and to explore possible explanations for litter relocation behavior. We observed 19 litters relocated by YBM mothers and 32 by GMGS mothers. Although YBM are much larger than GMGS, relocation distances for YBM (median = 46 m and range = 15–324 m) were not greater than those for GMGS (median = 79 m and range = 16–252 m), possibly because YBM home ranges in our study area were exceptionally small. Frequency of litter relocation was greater for GMGS (21% of litters produced) than for YBM (10%), perhaps because GMGS experience fewer social constraints or greater predation risk. We identified several possible costs (energy expenditure and vulnerability to predators while transporting young) and benefits (reduced exposure to predation risk, increased habitat quality, and social benefits) of litter relocation. Future studies should continue to explore litter relocations to better understand the ecological causes and consequences of this behavior.

Invasive plants and water availablity mediate outcomes of plant-pollinator interactions - W. Recart Gonzalez (2019)

Climate change, phenological shifts, and species interactions: Case studies in subalpine plant and migratory fish populations - Rebecca M. Dalton (2019)
Climate Change, Phenological Shifts, and Species Interactions:

Exploring mechanisms explaining coexistence patterns of Rhyacophila species (Trichoptera) in streams near the Rocky Mountain Biological Laboratory - A. Ruiz (2019)
Coexistence of closely related species can be explained by a number of biotic and abiotic factors. In Trichoptera (caddisflies), the patterns of coexistence of the species Rhyacophila in streams near the Rocky Mountain Biological Laboratory (RMBL) has been tracked for 43 years. This study is a continuation from previous student projects carried out in 2017 and 2018 to explore the mechanisms explaining patterns of coexistence of these caddisflies. In addition to coexistence patterns, data from previous studies include species preferences for streams of different altitude, size, water temperature, and the coverage of the nuisance diatom Didymosphenia geminata. The coverage of D. geminata varies among years (favored in low-flow years), and streams (favored in streams with lower levels of phosphorus). Previous studies considered those factors only at the scale of stream reaches, but microhabitat preferences within stream reaches by different species of Rhyacophila remain to be investigated. Another previously unexplored factor is resource partitioning of prey by these predatory caddisflies. Questions asked in this study include: 1) Do certain pairs of species coexist in stream reaches by partitioning microhabitats (specifically, current velocities, water depths, substrate particle sizes or coverage of Didymo?) 2) Do Rhyacophila species shift microhabitats in the presence of potential competitors? 3) Does partitioning of food (prey) resources explain coexistence of pairs of species of Rhyacophila? We addressed those questions by continuing surveys in seven out of eight long- term stream sites near RMBL and adding measurements of microhabitat and diet preferences of coexisting Rhyacophila species. We also surveyed eight small streams in the Upper East River drainage while waiting for water levels to be safe in the larger, long-term sites. Results showed that two species that typically coexist at warmer water sites (R. brunnea and R. valuma) did not partition microhabitats, while the two species that coexist in colder water sites (R. alberta and R. hyalinata) preferred different water depth and substrate microhabitats. We were unable to test effects of Didymo during this very high-water year. In addition, while we could not distinguish specific prey species in the gut contents of these caddisflies, one of each pair of coexisting species had significantly larger mouth gapes than the other, suggesting that they may partition prey species (larger: Baetis vs smaller: chironomids).

Snowmelt affects aphid (Aphis asclepladis) populations through soil moisture and host plant phenology - James H Den Uyl (2019)
Plant-insect interactions are ecologically important relationships that are greatly affected by climate change. Previous research concerning an aphid species (Aphis asclepiadis) and its host plant (Ligusticum porteri) has shown that aphid abundances correlate significantly with snowmelt date in the subalpine zone of the Rocky Mountains. The mechanisms underlying this phenomenon have not been previously identified. Our construction of a structural equational model identified soil moisture and plant phenology as two major pathways by which snowmelt indirectly affects aphids. By comparing aphid and host plant populations at different elevations and experimentally manipulating soil moisture we observed significant responses in aphid abundance, ant abundance, aphid predators, and some measures plant quality. While bottom-up processes may be playing a role in determining aphid abundances, top-down pressures appear to have much more control over this aphid dominated ecosystem. iii ACKNOWLEDGEMENTS I would like to acknowledge all the help, direction, and mentorship Dr. Emily Mooney provided me in the completion of this study. I would also like to thank Dr. Shane Heschel and Dr. Jeremy Bono for their guidance and participation in my graduate committee. A special thanks to Dr. Janel Owens and Phuong Nguyen for their work on honeydew analysis and Benjamin Davidson and Samantha Trail for their assistance in the field. This research was supported by a grant from the National Science Foundation Division of Environmental Biology (award # 1655914), a graduate fellowship from the Rocky Mountain Biological Laboratory, and support from the Biology Department at the University of Colorado at Colorado Springs. iv

Microbial communities across a hillslope-riparian transect shaped by proximity to the stream, groundwater table, and weathered bedrock - B. C. Thomas; P. B. M. Carnevali; A. Lavy; Jillian F. Banfield; Jiamin Wan; Tetsu Tokunaga; Wenming Dong; S. S. Hubbard; Kenneth Hurst Williams (Ecology and Evolution, 2019)
Abstract Watersheds are important suppliers of freshwater for human societies. Within mountainous watersheds, microbial communities impact water chemistry and element fluxes as water from precipitation events discharge through soils and underlying weathered rock, yet there is limited information regarding the structure and function of these communities. Within the East River, CO watershed, we conducted a depth‐resolved, hillslope to riparian zone transect study to identify factors that control how microorganisms are distributed and their functions. Metagenomic and geochemical analyses indicate that distance from the East River and proximity to groundwater and underlying weathered shale strongly impact microbial community structure and metabolic potential. Riparian zone microbial communities are compositionally distinct, from the phylum down to the species level, from all hillslope communities. Bacteria from phyla lacking isolated representatives consistently increase in abundance with increasing depth, but only in the riparian zone saturated sediments we found Candidate Phyla Radiation bacteria. Riparian zone microbial communities are functionally differentiated from hillslope communities based on their capacities for carbon and nitrogen fixation and sulfate reduction. Selenium reduction is prominent at depth in weathered shale and saturated riparian zone sediments and could impact water quality. We anticipate that the drivers of community composition and metabolic potential identified throughout the studied transect will predict patterns across the larger watershed hillslope system.

Floral reward strategies, visitor behavior, and plant reproductive outcomes - Jacob M. Heiling (2019)
Many plants that bear hidden or recessed floral nectar experience nectar robbing, the removal of nectar by a floral visitor through holes pierced in the corolla. Although robbing can reduce plant reproductive success, many studies fail to find such effects. We outline three mechanistic hypotheses that can explain when interactions between plants and nectar-robbers should be commensal rather than antagonistic: the non-discrimination (pollinators do not avoid robbed flowers), visitor prevalence (robber visitation is rare relative to pollinator visitation), and pollen saturation (stigmas receive sufficient pollen to fertilize all ovules with one or very few pollinator visits) hypotheses. We then explore these mechanisms in the North American subalpine, bumble bee-pollinated and nectar-robbed plant Corydalis caseana (Fumariaceae). We first confirmed that the effects of nectar robbing on female reproductive success were neutral in C. caseana. We then tested the three mechanisms underlying these neutral effects using a combination of observational studies and experiments. We found evidence for all three mechanisms. First, consistent with the non-discrimination hypothesis, pollinators failed to discriminate against experimentally robbed flowers or inflorescences even though naturally robbed flowers offered significantly lower nectar rewards than unrobbed flowers. Second, C. caseana was more commonly visited by pollinators than by nectar robbers, in accordance with the visitor prevalence hypothesis. Third, stigmas of unvisited flowers as well as those visited once by pollinators were saturated with pollen, with all stigmas bearing pollen loads several 1 orders of magnitude higher than the number of ovules per fruit, consistent with the pollen saturation hypothesis. Our investigation of the mechanisms driving the commensal outcome of nectar robbing in this system deepens our understanding of the ecology of nectar robbing and contributes to a more general understanding of the variation in the outcomes of interactions between species. 2

Volatile organic compounds as signals for pollinators and their consistency across years - L. Sharrett (2019)
Volatile organic compounds (VOCs) are emitted by every part of a plant and are believed to work as possible olfactory signals, drawing in pollinators and antagonists. This study was designed to address whether VOCs served as a signal to pollinators, indicating the size of the nectar reward. This part of the study focused on two populations of Ipomopsis aggregata plants. Another part of the 2019 study measured floral VOCs for six species in a dry meadow also studied in 2017 and 2018 to address the consistency of emission of VOCs across three years differing in environmental conditions including date of snowmelt. The total emission of volatiles by flowers of I. aggregata did not correlate detectably with the production of nectar. In the dry meadow experiment, the composition of volatile emissions changed significantly across the three years, particularly for Galium boreale in the late snowmelt year of 2019.

Adaptation and diversification of bluebells Mertensia spp., Boranginaceae - S. Y. Lin (2019)
Flowering phenology marks the transition from vegetative growth to reproduction and exposes plants to seasonally varying selective environments during flowering. Life-history trade- offs between time and size at reproduction suggest that early-flowering species should generally be smaller than late-flowering species. Furthermore, consistent seasonal variation in environmental conditions may generate seasonally varying selection on morphological traits (such as vegetative size and floral traits), potentially causing correlations between morphological traits and flowering phenology. Similarly, trait correlations may be driven by multiple traits responding in parallel to environmental gradients; for example, low air temperature and high wind velocity in high-altitude habitats might favour smaller species that also flower rapidly after snowmelt. To assess interspecific correlations between flowering phenology and other traits, I focused on 12 species of Mertensia (Boraginaceae) that have similar vegetative and floral morphology but differ greatly in size, flowering phenology, and altitudinal distribution. I developed two novel techniques to estimate flowering phenology of each species based on a single day’s survey, measured size and reproductive traits of each species, and used phylogenetic comparative methods to test for interspecific correlations among flowering phenology, size, floral traits, and altitude. Early-flowering Mertensia species were shorter in stature, produced fewer flowers, and occurred at higher altitudes than late-flowering species. However, traits of individual flowers (stigma–anther separation and floral volume) were not strongly associated with variation in flowering phenology or plant size. The evolution of flowering phenology within Mertensia has been associated with changes in plant size but not floral traits. Early-flowering species may be smaller because they have less time for growth before reproduction, and because short stature and early flowering are both adaptations to high-altitude environments. 9

Effects of weather and floral density on foraging activity of cavity nesting bees ( Osmia spp.) - I. Rivera; Lydia H. Wong; Jessica R.K. Forrest (2019)
Thermoregulation is an important factor for bee flight which ultimately contributes to an individual’s ability to forage and produce offspring. Rising temperatures could benefit insects by increasing their efficiency in reproduction and provisioning. However, warming could negatively impact floral resources, thereby indirectly affecting foraging and reproductive success in specialist bees negatively. In this study I investigated the effects of weather variation and floral density on individual foraging rate in subalpine populations of the solitary bee species ​Osmia iridis and Osmia coloradensis​ on individual foraging rate. I examined how temperature, percent cloud coverage and floral density affected the foraging rates and provisioning efficiency. Foraging rate did not increase with rising temperatures nor with increased floral densities. However, increased cloud coverage did decrease the foraging rates of bees, as expected. The results suggest that temperature, cloud coverage, and host floral density are not the only factors that affect the foraging rates of solitary bees and understanding the response to warming is critical to understanding the responses to global change in bee populations.

Effects of recreational trails on small mammal communities in north-central Gunnison County, Colorado - L. Macias (2019)
Human recreation can lead to changes in behavior and distribution patterns of wildlife populations. This project aims to (1) evaluate the effectiveness of the Hunt trap, a novel non- invasive technique used to estimate small mammal abundance (2) determine the distance from trails at which we see an effect on small mammal activity and (3) assess the impact of non- motorized recreational activities on rodent species abundance. We investigated these objectives at areas of high utilization using a non-invasive camera trap method at a series of locations throughout July and August 2019. Heavily used recreational trails did not show a significant impact on habitat utilization by several small mammal species. Nocturnal species including deer mice (Peromyscus maniculatus) activity was higher, however not significant, in proximity to trails. Diurnal rodents including golden-mantled ground squirrels (Callospermaphilus lateralis) and least chipmunks (Tamias minimus) did not exhibit a negative trail effect. Quantifying the impacts of human recreational disturbance on wildlife is essential for a functional ecosystem and establishing management policies regarding use of recreational trails.

The individual and combined effects of snowmelt timing and frost exposure on the reproductive success of montane forbs - Isaac O. Jensen; Pardee G.; Rebecca E. Irwin; David W. Inouye (Journal of Ecology, 2019)

Identifying the Impact of Biotic Interactions on Meadow Species Distributions in Sagebrush and Bunchgrass Dominated Systems - S. LaRocca (2019)
Understanding drivers of species distributions is an important challenge for more accurately projecting ecological change under climate warming. Species distributions have often been modeled using solely environmental factors as predictors. However, there is much recent data supporting the hypothesis that biotic interactions strongly influence species distributions at both local and global scales. This study aims to provide data on how existing plant communities alter the realized ranges of other species. By comparing species distribution model (SDM) predictions with field observations, we analyzed the effects of two taxa of dominant plant cover, sagebrush and a Fescue bunchgrass, upon the distributions of ~20 different herbaceous meadow species in a subalpine valley in western Colorado. This data will add to our understanding of how plant community dynamics interact with observed distributions across scales.

Does road dust affect growth rates in Ipomopsis aggregata? - David W. Johnson (2019)
The physiological effects of road dust on the wildflower rosettes Ipomopsis aggregata, scarlet gilia, are shown to non-significantly reduce their growth rate in two meadows near the Rocky Mountain Biological Laboratory. Growth rate was a proxy for the amount of photosynthesis that occurred in the rosettes during the summer. There were differences between the two site locations that suggest there are some unknown variables of microsite that were not explored. However, the overall trend does show that dusting treatments of rosettes reduced their growth over the course of the summer. Initial size of selected rosettes were bigger in Lower Maxfield Meadow than that of Upper Maxfield Meadow.

The depredation of Mountain White-crowned Sparrow (Zonotrichia leucophyrys oriantha) nests by the golden-mantled ground squirrel (Callospermophilus lateralis) and long-tailed weasel (Mustela frenata) - Ross R. Conover; Savannah Troy (The Wilson J. of Ornithology, 2019)
The identities of avian nest predators remain unknown in many systems. The Mountain White-crowned Sparrow (Zonotrichia leucophrys oriantha) is a high-elevation ground-nesting passerine for which only 4 of 15 suspected nest predator species have been confirmed. In this short communication, we confirm 2 previously suspected but unverified nest predators of Z. l. oriantha that were video recorded during the 2016 and 2017 summer breeding seasons. These nest depredation events include a golden-mantled ground squirrel (Callospermophilus lateralis) in 2016 and a long-tailed weasel (Mustela frenata) in 2017. Both predators were recorded removing nestlings.

The impact of climate change on Rocky Mountain plant communities: Differences in floral trait along an elevational gradient of transplanted communities - L. DuFresne (2019)
Alpine climates are seemingly adverse environments for plants. These habitats directly impact plants via pollinator scarcity and abiotic factors like extreme temperatures and precipitation that influence resource allocation. As a result, elevational gradients are natural laboratories that can be used to examine how climate shapes plant form, function, and diversity. The aim of this project is to assess the effects of temperature and snowmelt date on the floral traits and reproductive phenology of experimental transplanted communities along an elevational gradient. Traits measured in this study were flower length, diameter, petal length, and height of the highest flower; phenology stages recorded were bud, flower, withered petals, and fruiting. Data collection occurred along three subalpine meadow sites off of Washington Gulch Road in Crested Butte, CO, each of which contains transplanted turfs from higher/lower on the mountain as well as both transplanted and untouched control plots. Comparisons between controls on the elevational gradient show that diameter is least affected by changes in elevation, whereas height of the highest flower changes significantly. Additionally, floral traits measured in transplants are more similar to those of their original site than those in their destination site. This indicates a lesser degree of phenotypic plasticity and more genetic determinacy in the floral traits measured, which could pose serious concerns to the reproductive fitness of these communities in the future as climate change rapidly alters alpine environments.

Hyporheic Zone Microbiome Assembly Is Linked to Dynamic Water Mixing Patterns in Snowmelt-Dominated Headwater Catchments - K. D. Harris; Malak M. Tfaily; Audrey Sawyer; S. R. Bryant; C. M. Saup; Michael J. Wilkins; J. N. Christensen; Annika S. Nelson; Kenneth Hurst Williams (Journal of Geophysical Research: Biogeosciences, 2019)
Abstract Terrestrial and aquatic elemental cycles are tightly linked in upland fluvial networks. Biotic and abiotic mineral weathering, microbially mediated degradation of organic matter, and anthropogenic influences all result in the movement of solutes (e.g., carbon, metals, and nutrients) through these catchments, with implications for downstream water quality. Within the river channel, the region of hyporheic mixing represents a hot spot of microbial activity, exerting significant control over solute cycling. To investigate how snowmelt‐driven seasonal changes in river discharge affect microbial community assembly and carbon biogeochemistry, depth‐resolved pore water samples were recovered from multiple locations around a representative meander on the East River near Crested Butte, CO, USA. Vertical temperature sensor arrays were also installed in the streambed to enable seepage flux estimates. Snowmelt‐driven high river discharge led to an expanding zone of vertical hyporheic mixing and introduced dissolved oxygen into the streambed that stimulated aerobic microbial respiration. These physicochemical processes contributed to microbial communities undergoing homogenizing selection, in contrast to other ecosystems where lower permeability may limit the extent of mixing. Conversely, lower river discharge conditions led to a greater influence of upwelling groundwater within the streambed and a decrease in microbial respiration rates. Associated with these processes, microbial communities throughout the streambed exhibited increasing dissimilarity between each other, suggesting that the earlier onset of snowmelt and longer periods of base flow may lead to changes in the composition (and associated function) of streambed microbiomes, with consequent implications for the processing and export of solutes from upland catchments.

Social transmission of a novel foraging trait in yellow-bellied marmots - A. W. Evans (2019)
Social transmission of novel behaviors can be an adaptive technique to rapidly and flexibly change responses to the surrounding environment. Although the dynamics of social transmission have been studied in highly social birds, primates, otters, and bats, we lack a solid understanding of the dynamics of social transmission in less social species, for which weaker social relationships may be less conducive for social transmission. To explore this knowledge gap, we tested a facultatively social species, yellow-bellied marmots (Marmota flaviventer), for presence of social transmission in a novel foraging task. We introduced a novel foraging behavior into a wild population with a 2-action puzzle box and studied the diffusion of this trait through the colonies’ social network with network-based diffusion analysis (NBDA). In two out of four successful diffusion we found that a social transmission model fit better than an asocial model. From this we infer that social transmission is conditionally used by certain marmot groups and may thus be a cognitive ability used by wild groups of less social species.

The function of floral orientation in bluebells: interactions with pollinators and rain in two species of Mertensia (Boraginaceae) - S. Y. Lin; Jessica R.K. Forrest (Journal of Plant Ecology, 2019)
Aims Important Findings Pollinators are traditionally considered to be the primary agent of Mertensia brevistyla had a significantly more upright floral orienta- selection on floral traits. However, floral traits may also be under tion than M. fusiformis, and seed set was highest in upright M. bre- selection from abiotic agents (e.g. rain), which makes considering vistyla and in horizontal/pendant M. fusiformis stems, supporting an the relative importance of pollinators and abiotic selective agents adaptive function (via female fitness) of the interspecific difference on floral traits essential. The functional significance of floral orien- in orientation. However, floral visitor assemblages did not differ tation is often ascribed to pollinator attraction, but orientation can significantly between the two species; visitors did not exhibit sig- also protect reproductive structures from rain. Therefore, a study nificant preference for either orientation; and pollinator-mediated that incorporates both factors will enhance our understanding of selection on orientation was undetectable. Similarly, there was lit- the ecological roles of floral orientation in plant fitness. Mertensia tle effect of water on seed set in either species, regardless of floral brevistyla and M. fusiformis are herbaceous species that differ in orientation. However, pollen germinability was reduced in both their floral orientations. A series of field and laboratory experi- species by immersion in water; and water was more likely to contact ments was used to investigate the adaptive function of floral orien- anthers in M. fusiformis than in M. brevistyla, due to interspecific tation in these species, particularly with respect to pollinators and differences in floral morphology. We conclude that pollinators are rain. likely not the primary selective agent driving differences in orienta- tion in these Mertensia species. Instead, the negative effect of rain

Parasites Are Associated With Noisy Alarm Calls - K. Nouri; Daniel T. Blumstein (Front. Ecol. Evol., 2019)
Many animal signals used for mate choice assessment are condition dependent, but less is known about the condition dependence of other biologically important signals. We asked whether yellow-bellied marmot (Marmota flaviventer) alarm calls varied as a function of parasite infection and/or neutrophil:lymphocyte ratios (a measure of immunological challenge). We found that marmots infected with Eimeria, an intestinal parasite, had noisier calls. This is potentially because of an immunostimulating effect of Eimeria infection which may draw energy from nonvital functions. The results suggest calls potentially contain information about parasite status which could be used by receivers to estimate a caller’s condition. Future studies are required to determine whether infection influences caller reliability and how receivers respond to alarm calls from parasitized individuals.

Effects of spatial patterning of co-flowering plant species on pollination quantity and purity - Jonathan R. Thompson; H. F. Fung; Jane E. Ogilvie (Annals of Botany, 2018)

Plant dominance in a subalpine montane meadow: biotic vs. abiotic controls of subordinate diversity within and across sites - E. LaPlante; L.A. Souza (PeerJ, 2018)
Background. Understanding the underlying factors that determine the relative abun- dance of plant species is critical to predict both biodiversity and ecosystem function. Biotic and abiotic factors can shape the distribution and the relative abundance of species across natural communities, greatly influencing local biodiversity.

Impacts of drought gradient on pollen limitation in flowers in dry subalpine meadows - D. MacArthur-Waltz (2018)

First-order controls of soil and leaf moisture - Samuel Pierce (2018)

Direct and indirect effects of episodic frost on plants growth and reproduction in subalpine wildflowers - Pardee G.; Rebecca E. Irwin; David W. Inouye (Global Change Biology, 2018)

Spatial patterns and climate relationships of major plant traits in the New World differ between woody and herbaceous species - M. Bahn; B. J. McGill; R. K. Peet; J. C. Svenning; N. Morueta-Holme; S. K. Wiser; B. Boyle; K. Engemann; N. J. B. Kraft; Peter M. van Bodegom; I. Simova; C. Violle; et al. (Journal of Biogeography, 2018)

Habitat preference of an herbivore shapes the habitat distribution of its host plant - H. A. Affeldt; J. M. Frazier; N. M. Alexandre; J. W. Lee; A. D. Gloss; Parris T Humphrey; Noah K Whiteman (Ecosphere 9, 2018)
Plant distributions can be limited by habitat-biased herbivory, but the proximate causes of such biases are rarely known. Distinguishing plant-centric from herbivore-centric mechanisms driving differential herbivory between habitats is difficult without experimental manipulation of both plants and herbivores. Here we tested alternative hypotheses driving habitat-biased herbivory in bittercress (Cardamine cordifolia), which is more abundant under shade of shrubs and trees (shade) than in nearby meadows (sun) where herbivory is intense from the specialist fly Scaptomyza nigrita. This system has served as a textbook example of habitat-biased herbivory driving a plant's distribution across an ecotone, but the proximate mechanisms underlying differential herbivory are still unclear. First, we found that higher S. nigrita herbivory in sun habitats contrasts sharply with their preference to attack plants from shade habitats in laboratory choice experiments. Second, S. nigrita strongly preferred leaves in simulated sun over simulated shade habitats, regardless of plant source habitat. Thus, herbivore preference for brighter, warmer habitats overrides their preference for more palatable shade plants. This promotes the sun-biased herbivore pressure that drives the distribution of bittercress into shade habitats.

Heritable plant phenotypes track light and herbivory levels at fine spatial scales - S. Faries; A. C. Nelson-Dittrich; J. M. Frazier; A. D. Gloss; Parris T Humphrey; Noah K Whiteman (Oecologia, 2018)
Organismal phenotypes often co-vary with environmental variables across broad geographic ranges. Less is known about the extent to which phenotypes match local conditions when multiple biotic and abiotic stressors vary at fine spatial scales. Bittercress (Brassicaceae: Cardamine cordifolia), a perennial forb, grows across a microgeographic mosaic of two contrasting herbivory regimes: high herbivory in meadows (sun habitats) and low herbivory in deeply shaded forest understories (shade habitats). We tested for local phenotypic differentiation in plant size, leaf morphology, and anti-herbivore defense (realized resistance and defensive chemicals, i.e., glucosinolates) across this habitat mosaic through reciprocal transplant–common garden experiments with clonally propagated rhizomes. We found habitat-specific divergence in morphological and defen- sive phenotypes that manifested as contrasting responses to growth in shade common gardens: weak petiole elongation and attenuated defenses in populations from shade habitats, and strong petiole elongation and elevated defenses in populations from sun habitats. These divergent phenotypes are generally consistent with reciprocal local adaptation: plants from shade habitats that naturally experience low herbivory show reduced investment in defense and an attenuated shade avoidance response, owing to its ineffectiveness within forest understories. By contrast, plants from sun habitats with high herbivory show shade-induced elongation, but no evidence of attenuated defenses canonically associated with elongation in shade- intolerant plant species. Finally, we observed differences in flowering phenology between habitat types that could potentially contribute to inter-habitat divergence by reducing gene flow. This study illuminates how clonally heritable plant phenotypes track a fine-grained mosaic of herbivore pressure and light availability in a native plant.

Effects of Climate Change on Plants, Pollinators and Their Interactions - Pardee G. (2018)
1. Changes from historic weather patterns have affected the phenology of many organisms worldwide. Altered phenology can introduce organisms to novel abiotic conditions during growth and modify species interactions, both of which could drive changes in reproduction. 2. We explored how climate change can alter plant reproduction using an experiment in which we manipulated the individual and combined effects of snowmelt timing and frost exposure, as well as pollination and measured subsequent effects on phenology, peak flower density, frost damage, pollinator visitation, and reproduction of four subalpine wildflowers. The four plants included species flowering in spring to mid-summer. 11 3. The phenology of all four species significantly advanced and the bloom duration was longer in the plots from which we removed snow, but with species-specific responses to snow removal and frost exposure in terms of frost damage, flower production, pollinator visitation, and reproduction. The two early-blooming species showed significant signs of frost damage in both early-snowmelt and frost treatments, which negatively impacted reproduction for one of the species. Further, the earliest-blooming species had lower visitation rates in the snow removal plots, which might result in a mismatch with pollinators under advanced phenology. We also found lower fruit and seed set for the early-blooming species in the snow removal treatment, which could be attributed to the plants growing under unfavorable weather conditions. However, the later-blooming species escaped frost damage even in the plots where snow was removed, and experienced increased pollinator visitation and reproduction. 4. Synthesis. This study provides insight into how plant communities could become altered due to changes in abiotic conditions. While early-blooming species may be at a disadvantage under climate change, species that bloom later in the season may benefit from early snowmelt, suggesting that climate change has the potential to reshape flowering communities. 12

Relationships between CO2, thermodynamic limits on silicate weathering, and the strength of the silicate weathering feedback - Katharine Maher; Matthew Winnick (Earth and Planetary Science Letters, 2018)

Nesting aggregation as a predictor of brood parasitism in mason bees (Osmia spp.) - A. Groulx; Jessica R.K. Forrest (Ecological Entemology, 2018)

Consistent shifts in pollinator-relevant floral coloration along a Rocky Mountain elevation gradient - M. Gray; M. J. Stansberry; T. E. White; Kenneth D. Whitney; C.F. (Rick) Williams; Joshua S. Lynn (Journal of Ecology, 2018)

The Relationship between Soil Properties and Variation in the Morphology and Phenology of non-native mustard plant Thlaspi arvense in Subalpine Meadows - N. Djuric (2018)
The ability of soil to retain moisture can significantly impact the severity of droughts on plants. Deep, loamy soils retain moisture from snow melt into the dry season more efficiently than shallow, sandy soils that lose water to runoff and percolation. Soil depth and texture are thus significant in determining how plants respond to climatic challenges. Similarly, soil composition can impact the number of leaves, branching behaviour, and stem height of plants.Overall, there are many factors impacting the growth of plants and how they respond to challenges. Thlaspi arvense, an invasive mustard, has demonstrated success in diverse microhabitats in the subalpine meadows of Gunnison County. To determine what qualities of a microhabitat favour the growth of T. arvense, edaphic properties including moisture, pH, conductivity, organic content, and soil type were investigated. Distance from the road (as a proxy for disturbance) and elevation were also considered. These environmental characteristics were paired with morphological and phenological observations to understand how they might influence the behaviour of T. arvense. We recognize that genetic variation in our populations could influence conclusions made regarding the impact of environmental conditions on T. arvense. To understand these potential genetic effects, a common garden experiment was performed. Flowering time varied within genetically different populations sourced from opposite ends of the elevational gradient and grown in the same environment.

Evaluating Critical Thermal Tolerances of Solitary Bees - L. Naslund (2018)
Climate change is predicted to impact pollinators through both direct and indirect mechanisms: by altering physiological stress through warming temperatures and by changing species interactions through the altered phenology and abundance of food sources and competitors. While research has been done to evaluate the indirect mechanism of climate change on bees, less is known about the direct mechanism of thermal stress. To fill this gap, we measured the critical maxima (CTmax) of 20 distinct solitary bee taxa to 1) evaluate differences in CTmax among taxa, 2) identify the life history-traits that influence thermal tolerance, 3) determine how well CTmax predicts success in hotter-than-average years, as a proxy for conditions under long-term warming, and 4) evaluate if there is local adaptation of CTmax at different elevations within the same species. We found significant differences among taxa in average CTmax, driven primarily by Lasioglossum inconditum, Halictus virgatellus, Sphecodes sp., and Habropoda sp. which had significantly lower CTmax and Pseudopanurgus bakeri, Halictus rubicundus, Osmia spp. and Megachile spp. which had significantly higher CTmax than all additional species tested. In evaluating the traits related to differences in thermal tolerance, we found that only mass significantly predicted CTmax, with larger bees demonstrating higher CTmax. We found that CTmax predicted responses to a hotter-than-average year, indicating a relationship between thermal tolerance and fecundity effects. Finally, we found evidence for local adaptation in CTmax to elevation only in Hylaeus spp. and Megachile spp. Taken together, these results indicate a direct mechanism of climate change impact beyond alterations in the phenology and abundance of interacting species and indicate a species-specific response to warming based on both the breadth of thermal tolerance and local adaptation of populations.

Across Caste Variation of Proboscis Length and Within Caste Phenotype Matching of Subalpine Bumble Bees (Bombus spp.) - T. J. Barnes (2018)
Bumble bees (​Bombus ​spp.) are eusocial insects that typically consist of three castes, with each caste emerging and foraging at different times. Bumble bee queens and workers differ morphologically in several measurable traits, but morphological variation within species and within caste has not been well characterized. For the purposes of this study traits that are functionally significant are of particular interest, such as the length of the bumble bee’s proboscis, which bees use to extract nectar from flowers. Variation in the length of the bumble bee’s proboscis may affect their foraging behavior, and may inform what flowers they prefer to, or are capable of, feeding on. Variation of the length of the proboscis of five species of subalpine bumble bees was observed using 150 specimens of each species, comparing between species and between caste within those species. This study found that the queens of five of the five species have significantly longer proboscis than workers. Corolla length of several flowers that the bumble bees visited were measured and compared to the proboscis length. Phenotype matching, meaning flower preference according to proboscis length, was observed between species, but was not significant between castes of the same species.

Traditional plant functional groups explain variation in economic but not size related traits across the tundra biome - A. D. Bjorkman; Brieanne Forbes; H. D. Thomas; I. H. Myers-Smith; Johannes H. C. Cornelissen; S. C. Elmendorf; Benjamin Blonder (Global ecology and biogeography, 2018)

Climate Warming Drives Local Extinction in a Subalpine Meadow - M. L. Stanton; A. M. Panetta; John Harte (Mountain Views, 2018)

Costs and benefits of alternative food handling tactics help explain facultative exploitation of pollination mutualisms - Rebecca E. Irwin (Ecological Society of America, 2018)
AbstractMany mutualisms are taken advantage of by organisms that take rewards from their partners but provide no benefit in return. In the absence of traits that limit exploitation, facultative exploiters (partners that can either exploit or cooperate) are widely predicted by mutualism theory to choose an exploitative strategy, potentially threatening mutualism stability. However, it is unknown whether facultative exploiters choose to exploit, and, if so, make this choice because it is the most beneficial strategy for them. We explored these questions in a subalpine plant‐insect community in which individuals of several bumble bee species visit flowers both “legitimately” (entering via the flower opening, picking up and depositing pollen, and hence behaving mutualistically) and via nectar robbing (creating holes through corollas or using an existing hole, bypassing stigmas and anthers). We applied foraging theory to (1) quantify handling costs, benefits and foraging efficiencies incurred by three bumble bee species as they visited flowers legitimately or robbed nectar in cage experiments, and (2) determine whether these efficiencies matched the food handling tactics these bee species employed in the field. Relative efficiencies of legitimate and robbing tactics depended on the combination of bee and plant species. In some cases (Bombus mixtusvisitingCorydalis caseanaorMertensia ciliata), the robbing tactic permitted more efficient nectar removal. As both mutualism and foraging theory would predict, in the field,B. mixtusvisitingC. caseanawere observed more frequently robbing than foraging legitimately. However, forBombus flavifronsvisitingM. ciliata, the expectation from mutualism theory did not hold: legitimate visitation was the more efficient tactic. Legitimate visitation toM. ciliatawas in fact more frequently observed in free‐flyingB. flavifrons. Free‐flyingB. mixtusalso frequently visitedM. ciliataflowers legitimately. This may reflect lower nectar volumes in robbed than unrobbed flowers in the field. These results suggest that a foraging ecology perspective is informative to the choice of tactics facultative exploiters make. In contrast, the simple expectation that exploiters should always have an advantage, and hence could threaten mutualism persistence unless they are deterred or punished, may not be broadly applicable.

Rocky Mountain Biological Laboratory, Gothic CO Ecology of Place: Making Ecology and Evolutionary Biology Spatially Explicit - Ian Billick; J. S. Reithel; Ian K Breckheimer; Joshua S. Lynn; David W. Inouye; Kenneth Hurst Williams (Mountain Views, 2018)

50 years of mountain passes: A perspective on Dan Janzen's classic article - M. Kaspari; R. B. Huey; K. S. Sheldon; Nathan J. Sanders (American Naturalist, 2018)

Consequences of secondary nectar robbing for male components of plant reproduction - Bosak J. T.; Rebecca E. Irwin (American Journal of Botany, 2018)
Premise of the StudyOrganisms engage in multiple species interactions simultaneously. While pollination studies generally focus on plants and pollinators exclusively, secondary robbing, a behavior that requires other species (primary robbers) to first create access holes in corollas, is common. It has been shown that secondary robbing can reduce plants' female fitness; however, we lack knowledge about its impact on male plant fitness.MethodsWe experimentally simulated primary and secondary robbing in the monocarpic perennial Ipomopsis aggregata (Polemoniaceae), quantifying indirect effects on pollinator‐mediated pollen (dye) donation. We also assessed whether continual nectar removal via the floral opening has similar effects on hummingbird‐pollinator behavior as continual secondary robbing through robber holes.Key ResultsWe found no significant indirect effects of secondary robbing on a component of Ipomopsis male fitness. Although robbing did reduce pollen (dye) donation due to avoidance of robbed plants by pollinating hummingbirds, pollen donation did not differ between the two robbing treatments. The effects of secondary robbing on hummingbird behavior resembled effects of chronic nectar removal by pollinators. Our results indicate that hummingbird pollinators may use a combination of cues, including cues given by the presence or absence of nectar, to make foraging decisions.ConclusionsCombined with prior research, this study suggests that secondary robbing is less costly to a component of male fitness than to female fitness in Ipomopsis, broadening our knowledge of the overall costs of mutualism exploitation to total plant fitness.

Landscape, Science, and Social Reproduction - Laura Alice Watt (2018)
This chapter discusses the arc of Carolyn Merchant’s direct and indirect influences on work, particularly now forming a bridge between completed landscape history of Point Reyes National Seashore here in northern California, and developing a new focus on the history of the Rocky Mountain Biological Laboratory in Colorado. Wilderness designation in large portions of the surrounding Grand Mesa, Uncompahgre, and Gunnison National Forests and the Black Canyon of the Gunnison National Park have increasingly bureaucratized the landscape, requiring permits for research projects where the ecologists once had fairly free rein. From studying how ideas of preservation become inscribed on working landscapes, to investigating the ways in which field science shapes and is shaped by the landscape around it, the author continue to find inspiration and insight from Merchant’s scholarship.

Ammoniozippeite, a New Uranyl Sulfate Mineral from the Blue Lizard Mine, San Juan County, Utah, and the Burro Mine, San Miguel County, Colorado, USA - Jakub Plášil; Travis A. Olds; Joe Marty; Anthony R. Kampf; Barbara P. Nash (The Canadian Mineralogist, 2018)
Research Article| May 30, 2018 Ammoniozippeite, a New Uranyl Sulfate Mineral from the Blue Lizard Mine, San Juan County, Utah, and the Burro Mine, San Miguel County, Colorado, USA Anthony R. Kampf; Anthony R. Kampf § Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, U.S.A. § Corresponding author e-mail address: akampf@nhm.org Search for other works by this author on: GSW Google Scholar Jakub Plášil; Jakub Plášil Institute of Physics ASCR, v.v.i., Na Slovance 1999/2, 18221 Prague 8, Czech Republic Search for other works by this author on: GSW Google Scholar Travis A. Olds; Travis A. Olds Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, U.S.A. Search for other works by this author on: GSW Google Scholar Barbara P. Nash; Barbara P. Nash Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, U.S.A. Search for other works by this author on: GSW Google Scholar Joe Marty Joe Marty 5199 E. Silver Oak Road, Salt Lake City, Utah 84108, U.S.A. Search for other works by this author on: GSW Google Scholar Author and Article Information Anthony R. Kampf § Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, U.S.A. Jakub Plášil Institute of Physics ASCR, v.v.i., Na Slovance 1999/2, 18221 Prague 8, Czech Republic Travis A. Olds Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, U.S.A. Barbara P. Nash Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, U.S.A. Joe Marty 5199 E. Silver Oak Road, Salt Lake City, Utah 84108, U.S.A. § Corresponding author e-mail address: akampf@nhm.org Publisher: Mineralogical Association of Canada First Online: 25 May 2018 Online Issn: 1499-1276 Print Issn: 0008-4476 © 2018 Mineralogical Association of Canada The Canadian Mineralogist (2018) 56 (3): 235–245. https://doi.org/10.3749/canmin.1800002 Article history First Online: 25 May 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Anthony R. Kampf, Jakub Plášil, Travis A. Olds, Barbara P. Nash, Joe Marty; Ammoniozippeite, a New Uranyl Sulfate Mineral from the Blue Lizard Mine, San Juan County, Utah, and the Burro Mine, San Miguel County, Colorado, USA. The Canadian Mineralogist 2018;; 56 (3): 235–245. doi: https://doi.org/10.3749/canmin.1800002 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyThe Canadian Mineralogist Search Advanced Search Abstract The new mineral ammoniozippeite (IMA2017-017), (NH4)2[(UO2)2(SO4)O2]·H2O, was found in both the Blue Lizard mine San Juan County, Utah, and the Burro mine, San Miguel County, Colorado, USA. At both mines, it occurs as a low-temperature, secondary phase. The mineral is yellow to yellowish orange with pale yellow streak and fluoresces dull green yellow under 405 nm laser light. Crystals are transparent and have vitreous luster. It is brittle, with Mohs hardness of about 2½, splintery fracture, and three cleavages: {010} and {001} perfect, {100} good. The calculated density for the ideal formula is 4.433 g/cm3. Crystals are acicular to bladed, elongate on [100], up to about 0.2 mm in length at the Blue Lizard, and up to 2 mm at the Burro. Ammoniozippeite is optically biaxial (+) with α = 1.678(2), β = 1.724(3), γ = 1.779(3) (white light); the measured 2V is 87.1(5)°; r < v dispersion is weak; the optical orientation is X = b, Y = c, Z = a; and pleochroism is X colorless, Y orange yellow, and Z yellow orange (X ≪ Y < Z). Electron microprobe analyses (WDS mode) provided the empirical formulae [(NH4)1.97Na0.03]Σ2.00(U1.00O2)2(S1.01O4)O2·H2O and [(NH4)1.99K0.06Na0.04]Σ2.09(U1.01O2)2(S0.97O4)O2·H2O for crystals from the Burro and Blue Lizard mines, respectively. The five strongest X-ray powder diffraction lines for Burro mine material are [dobs Å(I)(hkl)]: 7.17(100)(020), 3.580(21)(040), 3.489(42)(203), 3.138(63)(223), and 1.6966(18)(229,426). Ammoniozippeite is orthorhombic, Ccmb, a 8.7944(3), b 14.3296(7), c 17.1718(12) Å, V 2164.0(2) Å3, and Z = 8. The structure of ammoniozippeite (R1 = 0.0396 for 932 reflections with Io > 2σI) contains edge-sharing zig-zag chains of pentagonal bipyramids that are linked by sharing corners with SO4 groups, yielding a [(UO2)2(SO4)O2]2– sheet based on the zippeite-type topology. The interlayer region contains two NH4+ groups and one H2O group pfu, statistically distributed over three sites. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The Effects of Climate-Driven Changes in Co-flowering between Linum lewisii and Potentilla pulcherrima on Pollinator Services - J. Robledo (2018)
Anthropogenic climate change is affecting many ecosystems. Changes in the melting of snowpack have altered flowering phenology in subalpine meadows. The subalpine meadows at the Rocky Mountain Biological Laboratory in Gothic, Colorado are experiencing shifts in co-flowering patterns. Two flowers, Linum lewisii and Potentilla pulcherrima, which had significant historical co-flowering overlap are now having 25% less overlap. The consequences of this shift are not well known and could be having an effect on plant-pollinator interactions. Although L. lewisii is self-compatible, outcrossing results in higher fruit and seed production. This means that pollinator services are important to L. lewisii, as it requires pollination to reproduce more effectively. This decrease in overlap may mean that there is less competition for pollinator services between these two species. This short-term study looked at pollinator visitation rates and pollen deposition on L. lewisii by applying different treatments to plots that decreased flowering overlap even further. Synchrony was manipulated by removing 100% and 50% of P. pulcherrima flowers in different sites. I expect that pollinator visitation rates to L. lewisii are higher and conspecific pollen deposition higher when there is less overlap. This hypothesis was not supported, however. I found that there was no significant difference between the treatments for pollinator visitation rates and conspecific pollen deposition. Assuming the experiment was conducted at a scale to which pollinators respond, this result suggests that climate-induced changes in co- flowering overlap will not have consequences for reproduction in this plant species. 1

Mix and Match: Transplanting symbiotic fungal partners across elevational gradients to gauge responses in migrating Elymus hosts - Kirk C. Anderson (2018)
Within the next century, ecosystems are projected to experience climate warming, with strong effects in mountain systems. Warming can alter species distributions, with documented upward migrations along elevation gradients. Species interactions may be important factors that promote species establishment during climate-induced migration. For plants, fungal interactions could help or hamper establishment, but little research has addressed this issue in mountain ecosystems. As plants move up-slope, they may bring fungal symbionts with them, encounter novel fungal consortia, or have the roles of their symbionts change. To investigate fungal symbionts during upward migration, I performed a field study that transplanted a low-elevation restricted grass species (Elymus elymoides) and broadly distributed grass species (E. trachycaulus) into low- and high-elevation sites. At each site, I imposed three soil treatments: sterile soil, fungal spores added from low-elevation sites, or fungal spores added from high-elevation sites, to create mismatches between plants and fungi (e.g., low elevation fungal spores added in high elevation sites). I hypothesized that plant performance would be reduced when the symbiont was mismatched with its abiotic environment. After two years, E. elymoides transplanted into high-elevation sites had a reduced survival when inoculated with low-elevation fungi relative to high elevation fungi or sterile soil, suggesting that low elevation fungal communities were pathogenic at high elevation. Unexpectedly, a fungal mismatch increased growth for both species in low- elevation sites. These results demonstrate the potential for climate change to induce mismatches between plants and fungal symbionts that could affect their future fitness and geographic distributions.

The Bureau of land management Kerber Creek restoration project - Romana M. Sutton (Digital Collections of Colorado (Colorado State University), 2018)
From May to December, 2009, I worked as an intern for the Bureau of Land Management in Saguache, Colorado, primarily on the Kerber Creek Restoration Project.Mining during late the 1800s to mid 1900s resulted in mine waste deposits along the creek.These wastes had detrimental effects on the creek and riparian zone.The goal of the Kerber Creek Restoration Project is to improve conditions in Kerber Creek and the surrounding watershed.During my internship with the Bureau of Land Management I monitored water quality, evaluated aquatic invertebrate abundance and composition, assessed fishery abundance and diversity, determined upland vegetation Cover Frequency Index, and collected preliminary stream channel morphological data.Working closely with Steve Sanchez, Natural Resources Specialist, on the project from May-December 2009 taught me

Transient LTRE analysis reveals the demographic and trait-mediated processes that buffer population growth - Adriana A. Maldonado-Chaparro; D. Z. Childs; Kenneth B. Armitage; Daniel T. Blumstein (Ecology Letters, 2018)
Adriana A. Maldonado- Temporal variation in environmental conditions affects population growth directly via its impact Chaparro,1,2,3* Daniel T. on vital rates, and indirectly through induced variation in demographic structure and phenotypic Blumstein,1,4 Kenneth B. Armitage5 trait distributions. We currently know very little about how these processes jointly mediate popu- and Dylan Z. Childs6* lation responses to their environment. To address this gap, we develop a general transient life table response experiment (LTRE) which partitions the contributions to population growth arising from variation in (1) survival and reproduction, (2) demographic structure, (3) trait values and (4) climatic drivers. We apply the LTRE to a population of yellow-bellied marmots (Marmota fla- viventer) to demonstrate the impact of demographic and trait-mediated processes. Our analysis provides a new perspective on demographic buffering, which may be a more subtle phenomena than is currently assumed. The new LTRE framework presents opportunities to improve our understanding of how trait variation influences population dynamics and adaptation in stochastic environments.

Facies reconstruction and detrital zircon geochronology of the Ingleside/Casper Formation - Rocca, Monique; Egenhoff, Sven; Singleton, John; Kajal Nair (Digital Collections of Colorado (Colorado State University), 2018)
Mixed siliciclastic-carbonate deposits of the Ingleside/Casper Formation in northern Colorado and southeastern Wyoming developed along the flanks of the Ancestral Front Range during the Late Paleozoic. This study establishes a sedimentological model for the Ingleside/Casper Formation along with using detrital zircon data to identify siliciclastic sediment sources for Late Paleozoic deposits in two Ancestral Rocky Mountain basins along the Ancestral Front Range and Uncompahgre Highlands. The stratigraphic successions of the Ingleside/Casper Formation display a diverse suite of carbonate and siliciclastic lithofacies in close lateral and vertical association with each other. The six different siliciclastic facies and their subfacies identified in this study include: (1) cross-bedded sandstone (tabular cross-bedded sandstone and trough cross-bedded sandstone), (2) horizontally-bedded sandstone, (3) massive sandstone, (4) conglomeratic sandstone, (5) ripple-laminated sandstone (asymmetric current ripples, moderately-steeply climbing ripples, and gently climbing ripples), and (6) silt-rich siliciclastic mudstone. The three different carbonate facies and their subfacies identified in this study include: (1) carbonate mudstone-wackestone, (2) carbonate packstone (packstone with non-skeletal grains and packstone with bioclasts), and (3) carbonate grainstone (grainstone with non-skeletal grains and grainstone with bioclasts). Thinning and/or pinching out of carbonate facies accompanied with a gradual increase in siliciclastic sedimentation is observed laterally across the study area from north to south. Eight stratigraphic intervals are recognized from correlations across a north-south transect of 120 km and each interval displays a lithofacies assemblage dominated either by carbonates or siliciclastics. Both carbonate and siliciclastic successions display small-scale fining-upward trends, with coarsening-upwards being partially or wholly absent across the study area. One of the eight intervals (termed Interval 6) is of significant interest in this study because it displays a unique lithofacies assemblage, with it being the only interval where trough cross-beds of facies 1B occur. Overall, carbonate units vary in the extent to which they onlap onto siliciclastic strata throughout the succession: Intervals 1 to 4 record a successive advance of onlap towards the south, whereas intervals 5 to 8 record a retreat of onlap and a successive northwards migration of carbonate strata. The nine different lithofacies and their subfacies identified in this study represent an array of shallow-marine paleoenvironments that include foreshore, shoreface, offshore transition, and offshore, and terrestrial settings comprising coastal eolian dunes and fluvial systems. Stratigraphic distribution of facies suggests that deposition in a shallow-marine environment alternated between dominantly siliciclastic and dominantly carbonate, mainly as a result of fluctuations in the input of siliciclastic sediment and its effect on carbonate deposition. In a distal direction, both siliciclastic and carbonate facies graded into carbonate mudstone that is identified as the most distal setting across all stratigraphic successions studied here. The Ingleside/Casper succession is interpreted to consist of two superimposed scales of sea-level fluctuations with the small-scale cycles represented by deepening-upwards successions across the study area, and a superimposed large-scale sea level curve recorded in the varying onlap of carbonates. The superimposed curve shows an overall transgression in the lower part of the succession succeeded by a regression in the upper part. Independent of this type of sea-level curve, dry eolian dunes dominated the stratigraphic record during Interval 6 and reflect a sharp change in climate to more arid conditions that accompanied the exclusive formation of dunes during this time. The sedimentological study suggests that deposition of the Casper/Ingleside Formation was governed by the two orders of sea-level oscillations and also climate change, both operating on two separate scales. The general fall in sea level and increase in aridity in the upper Ingleside/Casper Formation is attributed to the onset of a major Gondwanan glaciation phase that culminated during the Pennsylvanian-Permian transition which is likely to be located at the very top of this unit. Based on exclusively sedimentological considerations, this study therefore suggests that the Ingleside Formation, which is typically assigned a Permian age, was most likely deposited during the Late Pennsylvanian. This interpretation is also based on the correlation of the Coloradoan Ingleside Formation to the Casper Formation in Wyoming that contains a known Late Pennsylvanian fussuline assemblage. This study also presents new detrital zircon U-Pb geochronology data from the type section of the Ingleside Formation at Owl Canyon, and the Molas and Hermosa Formations near Molas Lake to understand Late Paleozoic sediment provenance and dispersal patterns across Colorado. U-Pb ages on 120-150 zircons were determined from each sample using LA-ICPMS, and ages with excessive discordance (>20% discordant or <5% reverse discordant) were rejected. All samples contain between 5% and 10% concordant Paleozoic aged zircons ranging from 330-490 Ma. Other significant age distribution peaks identified range between 990-1200 Ma, 1340-1500 Ma, 1600-1800 Ma, and 2500-3500 Ma. The wide spread of zircon age populations record a mixed Laurentian derivation comprising local and distal sediment sources. Paleozoic-age zircons are interpreted to coincide with high magmatic flux during the Taconic and Acadian orogenies in the Appalachian orogen. The diverse components in the U-Pb age data suggest that a widespread sand-dispersal system that transported local and distant sediment sources along the Ancestral Rockies was operational during the Late Paleozoic. Areas of eolian recycling observed in the Ingleside and Molas Formations points towards eolian systems playing an important role in transportation of distally-sourced zircons during Late Paleozoic time. Additionally, the U-Pb detrital zircon data indicate that a shift from non-marine to marine deposition across the Fountain-Ingleside transition was accompanied by a decrease in locally-sourced detrital zircons, most likely marking the cessation of Ancestral Front Range uplift. Conversely, the shift from non-marine to marine deposition across the Molas-Hermosa contact was accompanied by an increase in locally-sourced detrital zircons, most likely marking the initiation of the Uncompahgre uplift.

Determining the Effects of Climate-Induced Range Shifts on Caddisfly Population Dynamics - M. Hagaman (2018)
The geographic distribution of many freshwater insects is restricted in part by timing of snowmelt and the temperature of the water. Because of this, climate change is having a significant effect on the distribution of aquatic species around Gothic, Colorado. Scientists have documented that species typically found in lower elevation have begun to expand their range into higher alpine ponds. However, it is unknown how elevation will affect their population dynamics and rate of nutrient recycling. Caddisflies are a species of aquatic detritivores that are fundamental in providing nutrients to the ecosystem. Understanding how elevation affects caddisfly growth and population size is key to understanding how climate change will affect alpine communities globally. To have a better understanding of this concept, I studied 37 ponds ranging from 2,347 to 3,505 meters in elevation and looked at how elevation affected population density, adult body size, and adult emergence time of four species of caddisfly: Limnephilus externus, Limnephilus picturatus, Grammotaulius lorretae, and Asynarchus nigriculus. I took density samples of these species in each pond throughout the summer. Pupae were placed in emergence chambers, and adults were collected and measured. Elevation had a significant effect on the emergence time of Asynarchus. Elevation also positively affected Asynarchus density while it negatively affected Grammotaulius density. Pond type had a significant effect on Asynarchus thorax and abdomen weight at the Mexican Cut. This study was important because understanding how climate change affects foundational species may help us better understand its far-reaching effects on ecosystems.

Multiple models and experiments underscore large uncertainty in soil carbon dynamics - Gates, Timothy K.; J. A. Moore; B. Sridhar; G. Wang; M. D. Hartman; W. R. Wieder; E. Morrison; M. A. Mayes; Riley W.; R. Abramoff; A. Salazar; C. Averill; et al. (Biogeochemistry, 2018)
Soils contain more carbon than plants or the atmosphere, and sensitivities of soil organic carbon (SOC) stocks to changing climate and plant productivity are a major uncertainty in global carbon cycle projections. Despite a consensus that microbial degradation and mineral stabilization processes control SOC cycling, no systematic synthesis of long-term warming and litter addition experiments has been used to test process-based microbe-mineral SOC models. We explored SOC responses to warming and increased carbon inputs using a synthesis of 147 field manipulation experiments and five SOC models with different representations of microbial and mineral processes. Model projections diverged but encompassed a similar range of variability as the experimental results. Experimental measurements were insufficient to eliminate or validate individual model outcomes. While all models projected that CO2 efflux would increase and SOC stocks would decline under warming, nearly one-third of experiments observed decreases in CO2 flux and nearly half of experiments observed increases in SOC stocks under warming. Long- term measurements of C inputs to soil and their changes under warming are needed to reconcile modeled and observed patterns. Measurements separating the responses of mineral-protected and unprotected SOC fractions in manipulation experiments are needed to address key uncertainties in microbial degradation and mineral stabilization mechanisms. Integrating models with experimental design will allow targeting of these uncertainties and help to reconcile divergence among models to produce more confident projections of SOC responses to global changes.

Comparing the level of human disturbance in 2009 and 2018 at yellow-bellied marmot (Marmota flaviventer) colonies - E. Foli (2018)
Natural areas and the animal communities within them are inevitably affected by human disturbance. Human disturbance can occur through tourism, ecotourism, and simply human presence. The effect of a human on an animal can be detrimental, and has even been shown to cause increases of stress response, result in animals spending less time foraging and taking care of young and more time foraging, and influence development of habituation, or decreased sensitivity, to human presence (Frid & Dill, 2002; Maréchal et al., 2016, Knapp et al., 2013). In order to understand any effects human disturbance may have on yellow-bellied marmot colonies (Marmota flaviventer), human disturbance must first be documented. In 2009, a study documented the level of human disturbance occurring within 300m of five marmot colonies along the East River Valley in the form of light and heavy vehicles, bicycles, dogs, and pedestrians. By revisiting those methods of disturbance documentation, we produced a dataset measuring the level of human disturbance at the same five marmot colonies in 2018. Through comparison of the 2009 average rates of disturbance at each colony to the average rates in 2018, the correlation of rank order of total and light vehicles was significant, as well as the difference in average rates of heavy vehicles. This means that the colonies that experienced the highest vehicle traffic in 2009 still experience the most in 2018, while rates of heavy vehicles changed significantly from 2009 to 2018. Flight initiation distance of marmots did not change significantly in response to the beginning of the tourist season, indicating marmots may not change behavior for a short-term disturbance. Coupled with the documentation of human disturbance, this data can be used to further track human disturbance in the future and apply the documentation to studies that help understand the behavior and development of species in affected communities.

Plant functional trait change across a warming tundra biome - A. D. Bjorkman; N. Ruger; A. Blach-Overgaard; S. Normand; Brieanne Forbes; P. S. A. Beck; D. Georges; D. Blok; I. H. Myers-Smith; S. C. Elmendorf; Johannes H. C. Cornelissen; Benjamin Blonder (Nature, 2018)
Biome-wide relationships between temperature, moisture and seven key plant functional traits across the tundra and over time show that community height increased with warming across all sites, whereas other traits lagged behind predicted rates of change.

Rocky Mountain Biological Lab. Ecology of Place: Making Ecology and Evolutionary Biology spatially explicit - Ian Billick; J. S. Reithel; Ian K Breckheimer; Joshua S. Lynn; David W. Inouye; Kenneth Hurst Williams (Mountain Views, 2018)

Nesting Preferences of Osmia Bees in the Rocky Mountains - A. Gander (2018)
Osmia is a genus of solitary, cavity-nesting bees which will readily nest in artificial nest- blocks. Nest-blocks (or “trap-nests”) have long been used to study cavity-nesting bees and have recently been popularized for conserving bees in urban and agricultural systems. What attributes of the nest-block, its placement, and its proximal environment are attractive to Osmia? At each of several existing sites with nest-blocks already set up in the Rocky Mountains, CO, I measured the orientation and height of each nest-block; the health, circumference, and color of each tree with a nest-block; and the internal temperature of each nest-block. Osmia preferred warmer nest-blocks and blocks on larger trees, but there was no observed effect of any other variable on the number of nesting Osmia iridis. Future research should focus on measuring internal nest temperature for longer periods of time and placing nest-blocks on a wider variety of tree circumferences.

Developmental and social constraints on early reproduction in an asocial ground squirrel - Caitlin P. Wells; D. H. Van Vuren (Journal of Zoology, 2018)
AbstractFor short‐lived species, selection for early reproduction should be strong, yet females often delay their first reproductive bout. Delay in age of first reproduction due to developmental constraints, such as food availability, or social constraints, such as the inhibitory presence of breeding adults, has been documented for social mammals, but effects on asocial species are less well known. We evaluated the influence of developmental and social factors on early reproduction in a short‐lived, asocial species, the golden‐mantled ground squirrel (Callospermophilus lateralis). We found that females who reproduced as yearlings had been weaned earlier in their natal summer and experienced early snow melt during their yearling spring, suggesting the importance of access to high‐quality food at critical stages. Females were more likely to reproduce as yearlings when there were more adult males present during the breeding season, possibly because exposure to males accelerates reproductive maturity. Maternal presence had no effect on yearling reproduction, but yearlings with a littermate sister present were only 22% as likely to reproduce as females without a sister present, suggesting the effect of sibling competition well past weaning. Furthermore, the negative effect of a sister's presence, but not the presence of other females, suggests that relatedness affects reproductive competition in this asocial species.

Short-term, low-level nitrogen deposition dampens a trophic cascade between bears and plants - Joshua B. Grinath (Ecology and Evolution, 2018)
AbstractHuman activities have substantially increased atmospheric nitrogen (N) deposition in ecosystems worldwide, often leading to higher plant quality for herbivores and greater herbivory. Predators frequently suppress herbivores and indirectly benefit plants via “trophic cascades”, and the strength of these interactions can also depend on N availability. However, the evidence for N deposition effects on cascades primarily comes from studies of high‐level N deposition. Most terrestrial ecosystems currently receive elevated, but low‐level N deposition, and it is unclear whether this subtle N enrichment has any effect on cascades. Here, I asked whether low‐level N deposition alters a trophic cascade from black bears to plants in Colorado. In this ecological network, bears indirectly benefit plants by consuming ants and suppressing positive effects of ants on herbivores. Using a three year N enrichment experiment, I assessed changes in this cascade by measuring plant and arthropod responses to simulated N deposition, bear damage to ant nests, and the presence of mutualist herbivores and ants. I found that low‐level N enrichment and bears had interacting effects on plant reproduction. In ambient N conditions, bears indirectly increased plant reproduction by causing ant nests to become inactive and suppressing positive ant effects on herbivores that were detrimental for plants. Yet, bear‐induced ant nest inactivity had no effect on plant reproduction in N‐enriched conditions. When N was added, ants had greater positive effects on herbivores, but herbivores had weak effects on plants, potentially because plants were more resistant to herbivores. Ultimately, the results indicate that N enrichment strengthened resource control of the community and weakened plant–herbivore interactions and the cascade from bears to plants. This study suggests that common rates of low‐level N deposition are changing the strength of trophic cascades and may have already altered resource versus consumer control of ecological community structure in many ecosystems.

Invasion and restoration of western rivers dominated by Tamarix spp. - Deborah M. Finch; Steven W. Carothers; Kenneth J. Kingsley; John T. Stanley (2018)
Fifty years ago, riparian habitats were not recognized for their extensive and critical contributions to wildlife and the ecosystem function of watersheds. This changed as riparian values were identified and documented, and the science of riparian ecology developed steadily. Papers in this volume range from the more mesic northwestern United States to the arid Southwest and Mexico. More than two dozen authors-most with decades of experience-review the origins of riparian science in the western United States, document what is currently known about riparian ecosystems, and project future needs. Topics are widespread and include: interactions with fire, climate change, and declining water; impacts from exotic species; unintended consequences of biological control; the role of small mammals; watershed response to beavers; watershed and riparian changes; changes below large dams; water birds of the Colorado River Delta; and terrestrial vertebrates of mesquite bosques. Appendices and references chronicle the field's literature, authors, "riparian pioneers," and conferences.

Contact Metamorphism of the Mancos Shale: Impacts on Solute Release and Weatherability in the East River Valley, Gothic, CO - B. C. Sams (2018)
Alteration of rocks by contact metamorphism directly impacts rock pore structure and mineralogy, potentially decreasing weathering susceptibility and altering water residence times and release rates of aqueous solutes. Mountainous catchments, which can often be metamorphosed, are important for water and solute supply. Changes in the underlying lithology of a catchment can therefore directly impact water quality and solute release rates, imparting watershed scale changes in flow regimes and rate of flow within hydrologic systems. Here we aim to quantify differences in solute release rates from Mancos shale samples as a function of degree of metamorphism. Variable contact metamorphism of Mancos shale bedrock in the East River provides a natural test bed to investigate the role of underlying geology on weathering susceptibility, solute release rates and changing river chemistry in metamorphosed and unmetamorphosed sections of the Mancos shale. To analyze the relationship between rate of solute release and degree of metamorphism, three trials of column scale experiments were conducted for unmetamorphosed and metamorphosed Mancos shale samples collected in the East River, Colorado. Steady state calcium release rates from metamorphosed samples were found to be an order of magnitude higher than the release of calcium from unmetamorphosed samples. These solute release rates will help constrain watershed scale weathering and solute sources in the East River to better understand the relationship between rates of rock weathering and catchment solute release. Different solute release rates calculated from metamorphosed and unmetamorphosed samples at the column scale can be used to further constrain the spatial variation of weatherablity in metamorphosed and unmetamorphosed shale. Changes in release rates from unmetamorphosed and metamorphosed samples could be linked to differences present in sample mineralogy. iii

Using ecological stoichiometry to understand and predict infectious diseases - A. J. Sanders; B. W. Taylor (Oikos, 2018)
A key characteristic of host–parasite interactions is the theft of host nutrients by the parasite, yet we lack a general framework for understanding and predicting the interplay of host and parasite nutrition that applies across biological levels of organization. The elemental nutrients (C, N, P, Fe, etc.), and ecological stoichiometry provide a framework for understanding host–parasite interactions and their relation to ecosystem functioning. Here we use the ecological stoichiometry framework to develop hypotheses and predictions regarding the relationship between elemental nutrients and host–parasite interactions. We predict that a suite of host and parasite traits, stoichiometric homeostasis, host diet stoichiometry, and biogeochemical cycling are related to disease dynamics, host immunity and resistance, and bacterial growth form determination. We show that ecological stoichiometry is capable of expanding our understanding of host–parasite interactions, and complementing other approaches such as population and community ecology, and molecular biology, for studying infectious diseases.

Changes of dispersal ability in an isolated population - C. Bacon (2018)
Dispersal is a core mechanism in the maintenance of metapopulations. It maintains genetic diversity by connecting subpopulations and generates new populations to replace those that die out. However, as populations become more isolated, as occurs in habitat fragmentation, dispersal becomes more difficult. This should lead to selective pressure against dispersive individuals, causing a reduction in dispersal traits. Over time, this can lead to variation in dispersal traits among populations. We examine this idea using an extreme case of isolation in Euphydryas gillettii, a population that has remained completely isolated for forty years. By comparing this population to a baseline established using multiple populations in the native range of the species, we found that the isolated population showed characteristics indicative of relatively low dispersal. iv

Spatial and Temporal Patterns of Coexistence in Closely Related Rhyacophila (Trichoptera) Species - J. Yang (2018)
Environmental change affects the survival, interaction and co-existence of species within an ecosystem. We studied multiple species of Rhyacophila, a primitive genus of caddisfly that, in its larval state, lives at the bottom of cold, oxygen rich and fast flowing streams. Previous research has shown that six species, four of which are common, occur in the high montane, subalpine and alpine streams of the Upper East River Basin in the Gunnison National Forest. The goals of this study are: 1) to document the patterns of co-existence of different Rhyacophila species over space by sampling the same streams previously surveyed and to conduct species co- occurrence analyses to determine if there are any positive or negative associations between pairs of species; 2) to measure various environmental factors to obtain descriptive data about the typical niches of different species, which enabled us to generate hypotheses about potential causes of species co-occurrences; and 3) to conduct both seasonal and long-term temporal comparisons of Rhyacophila species co-occurrence patterns and environmental associations using the past 31 years of data. Results suggest that partitioning of space, time and competition are a few key mechanisms that can explain the observed patterns of Rhyacophila coexistence. Because Rhyacophila are particularly sensitive to environmental change, this study provides clues to climate change related impacts and serves as a comparative model for more threatened freshwater systems in Colorado.

Atypical flowers can be as profitable as typical hummingbird flowers - Mary V. Price; Nickolas M. Waser; Paul J. CaraDonna (The American Naturalist, 2018)
In western North America, hummingbirds can be observed systematically visiting flowers that lack the typical reddish color, tubular morphology, and dilute nectar of "hummingbird flowers." Curious about this behavior, we asked whether these atypical flowers are energetically profitable for hummingbirds. Our field measurements of nectar content and hummingbird foraging speeds, taken over four decades at multiple localities, show that atypical flowers can be as profitable as typical ones and suggest that the profit can support 24-h metabolic requirements of the birds. Thus, atypical flowers may contribute to successful migration of hummingbirds, enhance their population densities, and allow them to occupy areas seemingly depauperate in suitable resources. These results illustrate what can be gained by attending to the unexpected.

Effects of abiotic and biotic stress on plant fitness and herbivore defense in Boechera stricta - A. Carter (2018)
Abiotic and biotic factors influence plant fitness by altering the physical environment and resource availability. According to the stress gradient hypothesis, increasing physical stress in an environment increases positive plant-plant interactions and decreases negative interspecies interactions. I investigated how variance in abiotic stress modifies interactions between the wildflower Boechera stricta and its heterospecific plant neighbors. I also tested how heterospecific neighbor density may affect insect herbivory due to associational defenses. I conducted a common garden experiment where the density of neighbor vegetation naturally varied across microsites and rainout shelters were used to manipulate soil moisture. I collected data on B. stricta survival, fecundity, and insect herbivory under these varying combinations of drought and neighbor density. I also performed a potted plant experiment with B. stricta to isolate the relationship between neighbor vegetation density, herbivore defense, and plant fitness. From early season data in the common garden, I found a significant positive relationship between neighboring vegetation density and survival in B. stricta. I also found a significant positive relationship between neighboring vegetation and total fitness in B. stricta planted in 2015, suggesting facilitation. Consistent with the stress gradient hypothesis, plants in the rainout plots showed greater facilitation than those in the control plots. However, I found no significant interaction between neighboring vegetation and abiotic conditions (permissive vs. drought- stressed environments). From the potted plant experiment, I found a significant negative relationship between herbivory and neighboring vegetation, indicative of associational defenses. I also found an indirect negative relationship between neighboring vegetation and reproductive output, providing evidence for competition. Finally, I found genetic variation in these plant-plant interactions; of the two genotypes I tested, one experienced greater competitive effects of neighbors (evidenced by a stronger decrease in reproduction with increasing neighbor density), while the other benefited more from neighbors through associational defenses. Genotypic differences in the strength and direction of ecological interactions with neighbors indicates that the stress-gradient hypothesis may not be sufficient in understanding plant responses to stress.

Cumulative reproductive costs on current reproduction in a wild polytocous mammal - K. D. Kroeger; Jane M. Reid; Kenneth B. Armitage; Julien G. A. Martin; Daniel T. Blumstein (Ecology and Evolution, 2018)
The cumulative cost of reproduction hypothesis predicts that reproductive costs accumulate over an individual's reproductive life span. While short-term costs have been extensively explored, the prevalence of cumulative long-term costs and the circumstances under which such costs occur alongside or instead of short-term costs, are far from clear. Indeed, few studies have simultaneously tested for both short-term and cumulative long-term reproductive costs in natural populations. Even in mammals, comparatively little is known about cumulative effects of previous reproduction, especially in species with high variation in offspring numbers, where costs could vary among successful reproductive events. Here, we quantify effects of previous short-term and cumulative long-term reproduction on current reproduction probability and litter size in wild female yellow-bellied marmots (Marmota flaviventer) and test how these effects vary with age and between two contrasting environments. We provide evidence for cumulative long-term effects: females that had both reproduced frequently and weaned large litters on average in previous years had decreased current reproduction probability. We found no evidence for short-term reproductive costs between reproductive bouts. However, females weaned larger litters when they had weaned larger litters on average in previous years and had lower current reproduction probability when their previous reproductive success was low. Together these results suggest that, alongside persistent among-individual variation, long-term reproductive history affects current reproductive success.

Can Variation of Insect Populations Affect Mountain White-crowned Sparrow Daily Nest Survival? - A. Emerson (2018)
Mountain white-crowned sparrows’ (Zonotrichia leucophrys oriantha; hereafter MWCS) diet fluctuates across seasons given their changing nutrient requirements across life stages and environment. Insect population densities may influence the daily nest survival of MWCS who depend upon these organisms as food because the transition from egg to adult occurs in less than one year. Insect population fluctuation is influenced by temperature (˚C) and precipitation (cm), which were also examined in this nest survival study. Our objective was to determine nest success relative to insect prey availability with corresponding abiotic shifts. Nest data was collected in the upper East River Valley, Colorado, over a period of seven years (2005, 2007, 2008, and 2014-2017). We calculated daily nest survival using a time-sensitive, hierarchical modeling procedure in program MARK to determine the effects of insect population density (Diptera and Lepidoptera), weather, nest stage (incubation or nestling), clutch size, and seasonality (linear and quadratic). We found a slight, but significant negative correlation between nest survival and Diptera abundance and significant positive correlation between nest survival and Lepidoptera abundance. This study helps us to understand the resource requirements of MWCS throughout the nesting season so that we may predict future patterns in population fluctuation based on prey population density as impacted by temperature and precipitation.

Strong social relationships are associated with decreased longevity in a facultatively social mammal - Alexandra N. Lim; Svenja B. Kroeger; Dana M. Williams; Julien G. A. Martin; Daniel T. Blumstein (Proc. R. Soc. B, 2018)
Humans in strong social relationships are more likely to live longer because social relationships may buffer stressors and thus have protective effects. However, a shortcoming of human studies is that they often rely on self-reporting of these relationships. By contrast, observational studies of non-human animals permit detailed analyses of the specific nature of social relationships. Thus, discoveries that some social animals live longer and healthier lives if they are involved in social grooming, forage together or have more affiliative associates emphasizes the potential importance of social relationships on health and longevity. Previous studies have focused on the impact of social metrics on longevity in obligately social species. However, if sociality indeed has a key role in longevity, we might expect that affiliative relationships should also influence longevity in less social species. We focused on socially flexible yellow-bellied marmots (Marmota flaviventer) and asked whether female longevity covaries with the specific nature of social relationships. We quantified social relationships with social network statistics that were based on affiliative interactions, and then estimated the correlation between longevity and sociality using bivariate models. We found a significant negative phenotypic correlation between affiliative social relationship strength and longevity; marmots with greater degree, closeness and those with a greater negative average shortest path length died at younger ages. We conclude that sociality plays an important role in longevity, but how it does so may depend on whether a species is obligately or facultatively social.

Comparing Plant-Pollinator Network Structure between Drought and Non-Drought Years - A. Fife (2018)
Network analyses can be used to examine multi-species interactions and have been applied to many ecological interactions such as food webs, antagonistic relationships such as plant- herbivory, and mutualistic relationships. A particular focus has been on plant-pollinator interactions given their importance in driving terrestrial ecosystem functions. These networks can be structured with various attributes, which have been measured with network indices to describe the interactions. The indices of interest for this study are connectance, diversity of interactions, generality, vulnerability, nestedness, and specialization. Natural perturbations, such as drought or climate change, have the potential to alter the structure of these networks. We compared network structure between 2017, a year with normal precipitation and 2018, a year with extreme drought conditions in East River Valley in western Colorado, USA. Phenological mismatch and the decrease in relative abundances as a result of drought were predicted to cause changes in network structure. We constructed quantitative networks were built at three sites by collecting floral visitation data through capturing of pollinators. We compared the indices from 2017 and 2018 and the network structures showed a significant difference in diversity of interactions, meanwhile showing visible differences in connectance, nestedness, and specialization. Fife 3

Do socio-cultural traits and other demographics affect outdoor recreation constraints? The case for Mesa County, Colorado - T. Timothy Casey; Steven Ross Murray; Nathan Perry (Journal of Kinesiology & Wellness, 2018)
Physical activity from outdoor recreational pursuits is well known to be beneficial and has been encouraged by the US Surgeon General.  Specific constraints, often reflected in sociocultural issues, can be impediments to individuals participating in outdoor recreational activities.  Data were collected in conjunction with the Bureau of Land Management and the Mesa County Health Department in Colorado via surveys involving 580 residents of Mesa County regarding access to outdoor recreation.  Ordinal logistic regression was used to test whether ten different constraints to outdoor recreation were important to the respondents, given their age, sex, education, race/ethnicity, native language, and residential density.  The results indicated that the probability of experiencing outdoor constraints increased with lower education, Hispanic ethnicity, native Spanish speaking, and young age.  A second model, albeit with fewer respondents, was tested to include income.  The results of the second model were similar to the first model and also showed that lower incomes were associated with a higher probability of outdoor constraints.  The results of the two models indicated that socioeconomic status was a driving factor behind constraints to outdoor recreation.

Role of animal detritivores in the breakdown of emergent plant detrius in temporary ponds - A. J. Klemmer; M. E. Perchik; S. A. Wissinger (Freshwater Science, 2018)

Comparing detritus breakdown rates with and without detritivores in subalpine ponds with different hydroperiods - G. OMalley (2018)
It is widely accepted that in stream systems, detritivores accelerate the breakdown of detritus that has been “conditioned” by microbial decomposers. By accelerating the breakdown of dead plant material, detritivores release nutrients and smaller food particles that are used by downstream plants and animals, respectively . Standing-water ecologists have often assumed animal detritivores play a similar role in ponds and wetlands, but there are few published studies investigating the contribution of animal detritivores to the overall breakdown of detritus in standing water systems. In this study, I compared detrital breakdown rates with and without invertebrate detritivores in nine subalpine ponds that differ in hydroperiod (permanent, semi-permanent, and temporary) at the Mexican Cut in the East River Valley in the Colorado Rockies. The biomass dominant detritivores in these systems are cased caddisflies (Trichoptera: Limnephilidae). I placed 14 containers with 5g of sedge into 3 permanent and 3 semi-permanent ponds, and 10 containers in 3 temporary ponds, into the nine ponds. half of the containers were covered with coarse mesh (20 mm) to allow detritivore access, while the other half were covered in fine mesh (2 mm) to prevent detritivore access. Every ten days, a pair of containers (one coarse and one fine mesh) were removed from each pond to compare the rate of detritus breakdown through time. . On each date, the sedge was oven-dried and weighed, and detritivores in each container were identified. Detritus in the coarse mesh containers lost mass two times faster than the detritus in the fine mesh containers. Fine particulate organic matter increased at a higher rate in the coarse mesh containers, suggesting that these caddisflies have a significant impact on the breakdown rate of detritus. Additionally, the detritus broke down fastest in the permanent ponds.

Nutrient excretion rates of common aquatic taxa in high elevation ponds at the Mexican Cut - E. Jameson (2018)
Nutrient cycling is crucial for proper functioning of aquatic ecosystems. Animals play an integral part of this process, especially in nutrient poor ecosystems such as the high elevation ponds at the Mexican Cut Nature Preserve. Nutrients such as nitrogen (N) and phosphorus (P) are both limiting nutrients, and animal excretion increases the availability of these nutrients. We measured the excretion rates of common aquatic macroinvertebrates and the demand for nutrients in these pond ecosystems. We found excretion rates in aquatic macroinvertebrate taxa varied over several orders of magnitude for both nitrogen and phosphorus. It appeared that smaller taxa had higher mass-specific excretion rates, but we did not test these differences statistically. We compared nutrient demand between permanent and semi-permanent pond types, but did not observe any significant difference between the two. The macroinvertebrate community contributed significantly to pond N and P demand. Phosphorus contribution ranged from 25.5% to 67.7%, while macroinvertebrates contributed over 100% of N demand in all but one pond and as much as 352% of demand in one case. These results demonstrate the importance of these macroinvertebrate communities to nutrient cycling, and the potential consequences that climate driven changes in community composition could have on ecosystem functioning in these ponds.

Age, state, environment and season dependence of senescence in body mass - Jane M. Reid; Svenja B. Kroeger; Kenneth B. Armitage; Julien G. A. Martin; Daniel T. Blumstein (Ecology and Evolution, 2018)
AbstractSenescence is a highly variable process that comprises both age‐dependent and state‐dependent components and can be greatly affected by environmental conditions. However, few studies have quantified the magnitude of age‐dependent and state‐dependent senescence in key life‐history traits across individuals inhabiting different spatially structured and seasonal environments. We used longitudinal data from wild female yellow‐bellied marmots (Marmota flaviventer), living in two adjacent environments that differ in elevation and associated phenology, to quantify how age and individual state, measured as “time to death,” affect body mass senescence in different environments. Further, we quantified how patterns of senescence differed between two biologically distinct seasons, spring, and late summer. Body mass senescence had an age‐dependent component, expressed as a decrease in mass in old age. Overall, estimated age‐dependent senescence was greater in females living in the more favorable lower elevation environment, than in the harsher higher elevation environment, and greater in late summer than in spring. Body mass senescence also had a state‐dependent component, captured by effects of time to death, but only in the more favorable lower elevation environment. In spring, body mass gradually decreased from 2 years before death, whereas in late summer, state‐dependent effects were expressed as a terminal decrease in body mass in the last year of life. Contrary to expectations, we found that senescence was more likely to be observed under more favorable environmental conditions, rather than under harsher conditions. By further demonstrating that senescence patterns differ among seasons, our results imply that within‐year temporal environmental variation must be considered alongside spatial environmental variation in order to characterize and understand the pattern and magnitude of senescence in wild populations.

More social female yellow-bellied marmots have enhanced summer survival - A. Montero (2018)
For many animals, group living is an effective strategy to mitigate predation risk and ensure survival. However, in yellow-bellied marmots (Marmota flaviventer), increased sociality is associated with lower female reproductive success, decreased female longevity, and increased over-winter mortality for both males and females which raises questions about the adaptive value of sociality in this facultatively social mammal. Here we used social network analysis to ask questions about the relationship between specific attributes of sociality and summer survival, which is almost always attributable to predation. Yearling females have enhanced survival when they have stronger social relationships and are more central in their network. Adult female survival is not associated with social network traits, but females are more likely to survive the summer if they live in larger groups. Male survival is not associated with either social network trait variation or variation in group size. These findings identify a benefit for marmot sociality and an explanation for marmot colony social structuring.

Effect of blood parasites on secondary sexual characteristics and morphology in mountain white-crowned sparrows - E. A. Newman (2018)
Blood parasites affect numerous species of birds across the world and can cause serious population declines. Haemosporidian blood parasites in Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) are known to affect certain behavioral and morphological characteristics of hosts, including dominance-related characters like song. Blood parasites cause a host of symptoms, including anemia, reduced aerobic capacity, and increased metabolic demand. This study investigates the presence of various blood parasites and their influence upon crown-stripe width in males, a secondary sexual characteristic. According to the Hamilton-Zuk hypothesis, secondary sexual characteristics should be reduced in parasitized males and their breeding success consequently lowered. Birds were captured and processed at the Rocky Mountain Biological Laboratory, and for each bird a blood smear was taken as well as body measurements like tarsus, tail, and wing length. The presence of blood parasites Plasmodium, Haemoproteus, and Leucocytozoon were tested in relation to crown-stripe width, crown-stripe proportion, and tail, wing, and tarsus length. There was no significant effect of infection on crown-stripe width or proportion or wing and tarsus length, but there was a significant effect of Haemoproteus infection on increasing male tail length in males, and on Leucocytozoon x Plasmodium cross-infection on female tale length. This study warrants further research on effects of blood infections on morphological and behavioral phenotypes in Mountain White-crown sparrows, as climate change impacts vector populations and infection could increase in high- elevation areas.

High interspecific variation in nutrient excretion within a guild of closely related caddisfly species - Washko S. E.; J. A. Balik; B. W. Taylor; S. A. Wissinger (Ecosphere, 2018)
AbstractUnderstanding the amount of variation in functional traits between closely related species within guilds is critical for understanding links between community composition and ecosystem processes. Nutrient excretion is an important link between animals and their environments, and aquatic invertebrate communities can supply a considerable proportion of ecosystem nutrient demand via excretion. We quantified nitrogen (N) and phosphorus (P) excretion rates of 10 species of larval caddisflies that inhabit high‐elevation ponds and wetlands to determine the magnitude of variation in nutrient excretion within this guild. We found considerable interspecific variation in biomass‐specific excretion of nitrogen (eightfold differences), phosphorus (sevenfold differences), and the stoichiometric N:P ratios (fivefold differences). Through a meta‐analysis, we compared the variation within this guild to the variation found in other family‐level species assemblages to determine the overall range in the variation of nutrient excretion that could be expected across guilds and to determine whether the variation in this caddisfly guild is comparatively extreme, average, or low. The meta‐analysis revealed a large range in variation among guilds, and comparatively, the variation within this caddisfly guild is high for N excretion and intermediate for P excretion. The considerable variation within guilds revealed by our meta‐analysis suggests that functional redundancy among guild members is difficult to predict. Thus, some natural or human‐caused species gains or losses within biological groupings such as guilds and trophic levels could have little or no effect on ecosystem processes, whereas others could have very large effects.

Local adaption in Boechera stricta in the context of climate change - G. Steinmetz (2018)
This study examines whether climate change alters patterns of local adaptation in Boechera stricta (Brassicaceae). A common garden experiment was established in sites around the Rocky Mountain Biological Laboratory in Colorado. In the fall of 2017, Dr. Jill Anderson and her lab planted seeds from a broad elevational gradient into four common gardens in four treatments: a control (contemporary climate change condition), snow removal (a climate change simulation), snow addition (historical condition) and snow addition and supplemental water (another historical condition). In the growing season of 2018, we recorded data on three key early life history fitness components germination success, probability of survival of seedlings, and time until mortality for seedlings. As low elevation populations are exposed to hot and dry conditions, we predicted that low elevation maternal families would have greater fitness in treatments simulating ongoing climate change, whereas local adaptation would be more prominent under historical conditions. We found that low-elevation populations had greatest germination success across treatments and gardens. However, families from high elevation populations had enhanced probability of surviving and greater time until mortality. Overall, fitness was low, a likely consequence of the drought experienced during the winter of 2017- 2018.

Assessing science training programs: Structured undergraduate research programs make a difference - E. S. Nagy; C. Domingo; A. E. Wilson; E. G. Fernandez-Figueroa; T. D. Steury; J. L. Pollock; A. P. Summers; Ian Billick (BioScience, 2018)
Training in science, technology, engineering, and mathematics (STEM) is a top priority for driving economic growth and maintaining technological competitiveness. We propose that exposure to a rigorous research program as an undergraduate leads to success in a research STEM career. We compared the scientific outcomes of 88 participants from five National Science Foundation Research Experiences for Undergraduates (REU) Site programs with demographically similar applicants to assess the impact that formal, organized, and funded undergraduate summer research experiences have on participants. Our study demonstrates that REU participants are more likely to pursue a PhD program and generate significantly more valued products, including presentations, publications, and awards, when compared with applicants. We believe that key components of the program include funding for personal and professional needs; access to diverse intellectual, analytical, and field resources; and the presence of other undergraduate researchers who support each other and share their goals and interests.

Evolution of hydrothermal fluids from the deep porphyry environment to the shallow epithermal environment, The - Subaru Tsuruoka (Digital Collections of Colorado (Colorado State University), 2018)
The current understanding of magmatic-hydrothermal processes resulting in the formation of porphyry and epithermal deposits is based on case studies that focused on deposits such as Santa Rita porphyry copper deposit in New Mexico, the Refugio porphyry gold deposit in Chile, and the Summitville high-sulfidation epithermal deposit in Colorado. The present study re-examines these classical study sites to constrain the physical nature of the mineralizing hydrothermal fluids and to test recent models suggesting that metal transport can occur in the vapor phase. Careful petrographic investigations involving a combination of microanalytical techniques were performed to unravel paragenetic relationships in the three deposits. Based on fluid inclusion research on quartz closely associated with mineralization, it is shown that ore formation at Santa Rita occurred from a near-critical single-phase hydrothermal fluid under hydrostatic conditions. Observed fluid inclusion assemblages have salinities of ~11 wt% NaCl equiv. and homogenize at ~350–450°C. At Refugio, gold mineralization postdated the formation of banded quartz veins and appears to also have formed from a near-critical single-phase fluid at hydrostatic load. Microthermometric data on a small number of petrographically well-defined fluid inclusion assemblages yielded salinities of ~13 wt% NaCl equiv. and homogenization temperatures of <440°C. At Summitville, enargite precipitated from a hydrothermal liquid. Primary fluid inclusion assemblages have a salinity of ~7.5 wt% NaCl equiv. and homogenize at ~270°C. The paragenetically late gold mineralization formed from a hydrothermal liquid undergoing additional cooling and dilution with ambient water. The research provides new constraints on the formation of porphyry and epithermal deposits, highlighting the importance of near-critical hydrothermal fluids. It is shown that mineralization in porphyry deposits takes place late in the paragenesis and is caused by near-critical single-phase hydrothermal fluids derived from an actively degassing magma chamber. Vein formation occurs at the ductile-brittle boundary, which coincides with the transition from lithostatic to hydrostatic conditions. Epithermal mineralization is caused by hydrothermal liquids that originated from the near-critical single-phase hydrothermal fluids through isochemical contraction. The mineralizing hydrothermal liquids undergo cooling and dilution with ambient waters in the shallow subsurface.

The effect of surrounding bloom color on pan trap success in sampling Rocky Mountain bees - M. Turnley (2018)
On a global scale, bees are important pollinators but face declining populations. In order to monitor the health of bee populations and communities, accurate sampling methods are needed. One common sampling protocol utilizes a combination of pan-trapping and sweep netting. While pan- trapping has its benefits in removing observation bias, there is limited information on how surrounding flower color impacts the success of similarly colored pan traps. We analyzed a long- term data set from the Rocky Mountains (Colorado, USA) to gain a better understanding of the degree to which flower color biases pan trap success. Bees were sampled in 16 sites every two weeks over a nine-year period. Calculating the proportions of bees caught in certain colored pan traps as well as the proportions of certain colored flowers available allowed us to model the relationship between the two factors. We found that similarly colored surrounding bloom color had a small but statistically significant impact on pan trap success in sampling bees, with similar color reducing trap success. Considering this bias, we recommend recording flowering species abundance, richness, and evenness when bees are sampled so that the effects of flower color bias on pan trap success can be controlled statistically in future research.

Are ants botanists?: Ant associative learning of plant volatiles - G. Zapata (2018)
Ants are important members of most terrestrial ecosystems, and often forage in plant canopies where they occasionally participate in mutualisms with either the plants, or aphids that live on the plants. To participate in these mutualisms, the ants must first find them, and it is not clear how ants do this while foraging in the field. It is known that while ants forage in plant canopies they encounter many plant volatiles. There is also some laboratory evidence of associative learning in ants. This leads to the hypothesis that the ants may be learning to recognize the scents of plants that host resources, and preferentially forage on similar smelling plants. In this study we explore whether ants exhibit an association between the scent of a plant, and a honey reward, and whether this is dependent on the local plant density, and thus scent density, in the surrounding area. The two plants used in the study were Helianthella quinquenervis. an ant mutualist, and Ligusticum porteri a host for aphids, another ant mutualist, allowing us to better understand how this relationship may affect the plants as well. We found that ant foraging may be affected by both the surrounding density of resources, and associative learning. This is important as it brings us closer to understanding how ants interact with their environments across trophic levels, as well as how they and their mutualists may be affected by changes in the environment.

The Effects of Declining Aspen Forest Health on Rocky Mountain Birds - J. D. Gerber (2018)

Polyploidy influences plant-environment interactions in quaking aspen (Populus tremuloides Michx.) - F. C. Meinzer; J. R. Brooks; G. L. Cullinan; B. T. Greer; Christopher Still (Tree Physiology, 2018)

Effects of Ant Presence on Nicrophorus investigator’s Reproductive Success - O. Ortuno (2018)
Burying beetles require carrion in order to successfully reproduce and they compete with vertebrate scavengers, other burying beetles, ants, flies, fungi, and microbes for this ephemeral resource. Burying beetles have mechanisms to combat competition from fly eggs, fungi, and microbes, but interactions between ants and beetles have not been extensively studied, and are not yet well understood. Interactions between the ant species Tapinoma sessile and the burying beetle Nicrophorus investigator may yield a diffuse mutualistic relationship involving the predation of undesired dipteran eggs from the carrion. This study found fly presence reduced successful carcass sequestration by Nicrophorus investigator, with fly presence at the carcass leading to the beetle’s complete failure to bury. Ants (T. sessile, Formica fusca, Formica rufa, Myrmicinae subfamily) were found to have a conditional interaction with flies, for their presences in tandem increased beetle burial success, while pure ant presence was still negative for successful carcass burial.

Synchronization of speed, sound and iridescent color in a hummingbird aerial courtship dive - B. G. Hogan; M. C. Stoddard (Nature Communications, 2018)
Many animal signals are complex, often combining multimodal components with dynamic motion. To understand the function and evolution of these displays, it is vital to appreciate their spatiotemporal organization. Male broad-tailed hummingbirds (Selasphorus platycercus) perform dramatic U-shaped courtship dives over females, appearing to combine rapid movement and dive-specific mechanical noises with visual signals from their iridescent gorgets. To understand how motion, sound and color interact in these spectacular displays, we obtained video and audio recordings of dives performed by wild hummingbirds. We then applied a multi-angle imaging technique to estimate how a female would perceive the male's iridescent gorget throughout the dive. We show that the key physical, acoustic and visual aspects of the dive are remarkably synchronized-all occurring within 300 milliseconds. Our results highlight the critical importance of accounting for motion and orientation when investigating animal displays: speed and trajectory affect how multisensory signals are produced and perceived.

Art/Science collaborations: new explorations of ecological systems, values, and their feedbacks - O\'Connell K. E.; Landsbergen K. J.; Borden D. B.; Wysong L.; Cheney K.; B. G. Merkle; C. A. Penick; Crystal-Ornelas R.; Schulze M.; LeRoy C.J.; Ellison A. M.; Bosanquet E.; et al. (Ecological Society of America, 2018)

Flannelmouth Sucker: The Ironhorse of the Colorado River Basin - C Nate Cathcart (Fisheries, 2018)

How does road dust influence Ipomopsis pollination? - N. Centeno Armenta (2018)
Premise of research. Road dust affects the quantity of pollen received by Ipomopsis aggregata flowers, with dusty flowers receiving less pollen than undusty flowers. One possibility is that hummingbird pollinators visit dusty flowers less and deliver less pollen. This could happen if dusty flowers produce less nectar. Methodology. I collected a total of ninety-one I. aggregata flowers from experimentally dusted and non-dusted plants in Maxfield Meadow. The flowers had been enclosed in drinking straws for twenty-four hours beginning when they were elongated buds. I measured the nectar quantity (mg of sugar), flower length (mm) and nectar concentration. In addition to nectar measurement, a total of eight censuses were done every three days to count the total number of flowers per plant produced over the 2018 flowering season Pivotal results. Dusted I. aggregata flowers were shorter than undusted flowers and produced less nectar. These two findings may be related since flower size and nectar production were positively correlated. Conclusion. There are some factors that could have caused variation in the data. Two mechanisms are discussed, which refer to the quantity of nectar such as water limitations and bud’s morphology when enclosed in the straw.

Characterizing nectar content in wet and dry subalpine meadows during an extreme summer drought - A. Murphy (2018)
Pollinating bees visit flowers in order to forage for nectar and pollen, their major sources of nutrition. The plant communities that a bee interacts with vary across time and space, as different flower species dominate different habitats. One key driver of the spatial variation in plant communities is soil moisture, which creates distinct wet and dry habitats in the subalpine meadows around the Rocky Mountain Biological Laboratory (RMBL). These different flower species provide different nutritional rewards for visiting bees by producing varying amounts of sugar. Relatedly, flower species have differential responses to drought, and the very dry summer of 2018 represented a significant water challenge to flowering plants. We found that over the course of the season, wet and dry meadows contained the same amount of nectar sugar, based on the 13 species we measured. At certain time points, however, dry meadows contained more nectar owing to higher flower abundances. As expected, we also found species-specific responses to precipitation, with 3 of 4 species increasing their nectar volume and decreasing their nectar concentration once regular summer rains began, ending a period of extreme dryness. In 2 cases, D. barbeyi and M. ciliata, the volume and concentration responses counteracted each other, meaning that flowers produced the same amount of sugar during the drier and wetter periods. These responses may have implications for bee foraging because highly concentrated nectar in small volumes constitutes a poorer food source for bees, and bees are sensitive to sugar and viscosity cues.

Are Hylemya avoiding dusted Ipomopsis aggregata for good reason? - C. Rosas (2018)
Waser et al. (2016) found that road dust consistently reduces the pollen received by Ipomopsis aggregata flowers but does not consistently reduce seed set. Over three years we tested the hypothesis that the reason undusted plants do not have higher seed sets is that more of their fruits are eaten by larvae of Hylemya sp. (Anthomyiidae), a predispersal seed predator. In all three years, Hylemya indeed oviposited on a greater fraction of the flowers of undusted than dusted plants, though the overall oviposition rate varied among years. In 2017 and 2018 we also compared the fates of Hylemya eggs laid on dusted and undusted flowers to determine whether the flies were choosing undusted plants because their eggs are more successful there. In 2017, 33.42% of eggs laid on dusted flowers and 55% of eggs laid on undusted flowers successfully hatched into a larva. In 2018, the success rate was 48.6% and 21.8% on dusted and undusted flowers, respectively. We conclude that Hylemya oviposition preferences are adaptive and likely contribute to the inconsistent effects of road dust on Ipomopsis reproduction.

An integrative study of marmot responses to ecotourism - J. Nelson (2018)
Human disturbance in the form of ecotourism alters behavior many species and may impact fitness but few studies take an integrative approach to quantify impact in various ways to test for variation in physiological, behavioral, and consequential life history and demographic traits. We extended a previous study on antipredator behavior for yellow-bellied marmots (Marmota flaviventer) by controlling for natural predation and by splitting the data by marmot age group. In addition, we tested the assumption between altered behavior and a decreased fitness by analyzing different physiological traits. Using the same 2009 disturbance data of vehicles, hikers, bicycles, and dogs as the previous study, we analyzed the relationship between the different types of disturbance with the variables of stress, mass gain, summer survival, and annual survival from that same year. We fit models to each age class for each type of disturbance for each variable. We found that, across all variables, juvenile marmots were most sensitive to human disturbance. Behavioral traits were more sensitive to variation in human disturbance than physiological traits. Mass gain rate, a fitness correlate, was relatively impacted by disturbance, but does not impact overall marmot fitness. Despite behavioral and some physiological impacts of human visitation, variation in visitation does not explain marmots’ likelihood of surviving the summer or to the next year. This suggests that marmots are compensating for behavioral modifications, the mechanisms of which are not yet known.

Host-parasite ecology of Baetis bicaudatus mayflies and Gasteromermis sp. nematodes in high-altitude streams - K. J. Cromwell (2018)
Parasite-induced changes to host dispersal potentially influence the distribution of parasites and infection risk for hosts. Gasteromermis is a castrating endoparasitic nematode that infects both males and female mayflies (Baetis bicaudatus) but feminizes male hosts and manipulates them to disperse parasites to aquatic habitats via a mimicry of female oviposition behavior. In a stream network with high spatial heterogeneity in parasitism we used surveys and a large-scale field manipulation to 1) evaluate parasite effects on host dispersal capacity and site selection, and 2) test whether experimentally increasing host oviposition habitat would increase immigration of parasitized hosts, with subsequent increases in parasite recruitment and prevalence in the next generation. Initially assuming that manipulation benefits the parasite by increasing host encounters around oviposition sites, we predicted the parasite would not affect host dispersal capacity or site selection, and that more parasites would be dispersed to sites with abundant oviposition habitat subsequently increasing parasite transmission. In contrast to predictions, we found that parasites decreased host dispersal capacity (flight muscle ratio) and <2% of adult mayflies captured at oviposition sites were parasitized. We also observed a negative relationship between the flight muscle ratio of hosts and the percent biomass of parasite they contained, consistent with a tradeoff between parasite growth and host dispersal capacity. Furthermore, experimentally increasing oviposition habitat available for dispersal of hosts in natural streams had no effect on parasite recruitment or host infection risk. We conclude that the variability in suitable habitat that limits host recruitment does not limit its parasite and, therefore, does not contribute to observed spatial patterns of infection. Instead, life history events that occur in the months between when parasites are dispersed and when their offspring infect the next generation of hosts disconnect dispersal dynamics from recruitment and dilute colonization effects. Therefore, heterogeneity in infection rates may be shaped more strongly by post-colonization conditions within patches than by between-patch differences that influence dispersal.

Effects of Light Availability on Aspen Understory Species - Marco Castaneda (2018)
Trembling aspen (Populus tremuloides) is a keystone species found throughout North America. P. tremuloides is a successional species which aids the regeneration of ecosystems after disturbance. However, climate change is altering aspen forest dynamics. Aspen forest die- off in the American Southwest is predicted to increase in the next few years as temperatures and drought increase. As forests change, so does their understory. Forest die-off will affect the understory plant communities, which play crucial role on regional biodiversity. In this study, the effect of aspen canopy light transparency was measured to find its impact on species richness and abundance of aspen understory shrub, grass and forbs in the Gunnison National Forest (Colorado). The hypothesis is that aspen understory forbs will decrease in richness and abundance, aspen understory shrub and grass species will increase in richness and abundance with increasing canopy light availability in the form of LAI. Aspen overstory and understory photographs were taken. The overstory photographs were analyzed for LAI and the understory photographs were analyzed for richness and abundance. The results of the analysis did not express any negative relationships between forbs and light availability. The results did not show any positive relationship between grasses/shrubs and light amiability. Indicating that LAI does not affect understory species richness and abundance.

Pocket gopher (Thomomys talpoides) soil disturbance peaks at mid-elevation and is associated with air temperature, forb cover, and plant diversity - Samuel Canfield; Jeremy Keene; Ross R. Conover; Jennifer A. Rudgers; Joshua S. Lynn (Arctic, Antarctic, and Alpine Research, 2018)
Burrowing mammals can be ecosystem engineers by increasing soil aeration and erosion and altering the structure of plant communities. Studies that characterize the constraints on the distributions of fossorial mammal disturbances to soil can help predict changes in ecosystem engineering under future climates. We quantified the density of soil disturbances caused by Thomomys talpoides (northern pocket gopher) over replicate elevation gradients spanning 2,700–4,000 m a.s.l. in the Upper Gunnison Basin, Colorado, USA. As a conceptual framework for predicting biogeographic variation in soil disturbance, we used the abundant center hypothesis (ACH), which proposes that species abundance declines monotonically away from the most abundant location in its distribution, with the assumption that ecosystem engineering scales with gopher abundance. We also evaluated the relative importance of abiotic and biotic variables as correlates of soil disturbance. Gopher disturbance peaked at mid elevations (~3,150 m), supporting the ACH. The best model for predicting gopher-caused soil disturbance contained both abiotic and biotic variables, with increased soil disturbance where mean annual temperature, forb cover, and plant diversity were greatest. Results suggest that mountain ecosystems may experience increases in gopher-caused soil disturbance as climate warms, possibly accompanied by increases in plant diversity and forb cover.

A model for leaf temperature decoupling from air temperature - S. T. Michaletz; Benjamin Blonder (Agricultural and Forest Meteorology, 2018)
Abstract Leaf temperature (Tleaf) influences rates of respiration, photosynthesis, and transpiration. The local slope of the relationship between Tleaf and Tair, β, describes leaf thermal responses. A range of values have been observed, with β β  = 1 indicating poikilothermy where Tleaf tracks Tair, and β >1 indicating megathermy where Tleaf increasingly exceeds Tair. However, theory for variation in β has not been developed. Here we derive an equation for β that predicts how it varies with multiple trait and microenvironment variables. The approach also predicts how maintenance of Tleaf away from lethally high values may help explain regulation of stomatal conductance (gS). The work delineates contexts in which each class of leaf thermal response is expected and develops concepts for predicting leaf responses to thermally extreme environments.

Ecological causes and consequences of flower color polymorphism in a self pollinating plant (Boechera stricta) - Emily Mattoon; Robin Bingham; Priya Vaidya; Michaela Keefe; Ansley McDurmon; Lee C-R (New Phytologist, 2018)

Dispersal, Wing Morphology and Physiology relationships in Euphydryas Gillettii and implications for conservation - O. Shrestha (2018)
Dispersal is important for recolonization, migration and maintenance of local metapopulations and populations, in case of disruption in an animal's habitat. Morphology (wing loading and wing aspect ratio) and physiology (metabolic rates) are features that have been shown to explain dispersal processes in insects. However, there are no studies indicating the direct relationship between morphology and metabolic rates in association with dispersal. I studied Euphydryas gillettii butterflies at Rocky Mountain Biological Laboratory, Colorado to assess the link between wing morphology and metabolic rates and their influence on dispersal within different sites at RMBL. Individuals that dispersed to other sites had greater wing wear (an age estimate) and greater wing loading. The total flight distance increased with increasing residual resting metabolic rate (RMR), that is, RMR adjusted for body mass. Residual flight metabolic rate (FMR) and peak metabolic rates (PMR) were related to wing loading. Residual FMR was greater for greater wing loading. Residual PMR was also greater for greater wing loading, but only in females. Overall, greater wing wear, greater wing loading and greater RMR are indicative of better dispersal in E. gillettii, but these three morphological and physiological characteristics are not linked to each other. These findings regarding dispersal characteristics of E. gillettii butterflies can help inform conservation strategies prior to any reintroduction and translocation efforts. More species-specific dispersal studies underpinning an organism's dispersal mechanisms can minimize difficulties due to unpredicted dispersal reportedly faced by managers during the translocation-reintroduction processes. v

The impacts of early snowmelt and summer precipitation on the physiology and leaf morphology of Ipomopsis aggregata - Jocelyn Navarro (2018)
Climate change is occurring, and the effects will be visible all over the planet. In a subalpine ecosystem, earlier snowmelt and changes in summer precipitation are predicted to occur due to an increase in air temperature. During the summertime, this variation may lead to changes in traits, a process known as phenotypic plasticity. In plants, these plastic changes could occur in morphological traits or physiological traits. This study aimed to find the impact of an earlier snowmelt as well as variation in summer precipitation on traits in ​Ipomopsis aggregata​, a subalpine herb. In this study, we manipulated the snowmelt date and summer precipitation and measured three traits, photosynthetic water-use efficiency, specific leaf area, and trichome density, to determine if the environmental constraints are impacting the plant’s physiology and leaf morphology. Plants that had experienced less precipitation had a higher photosynthetic water-use efficiency, but still had lower photosynthetic rates. Water-use efficiency was similar for plants receiving a 50% reduction in summer rainfall and plants forced to bloom one week early but receiving normal rainfall. ​There was no detectable impact of date of snowmelt or amount of precipitation on the specific leaf area of the plants just 9 days after the onset of the precipitation treatments.

Disintegration of the leaf economic spectrum within and across Quaking aspen (Populus tremuloides) genotypes - Rieksta J. (2018)
1. The leaf economic spectrum (LES) describes consistent and strong correlations among plant functional traits in a multidimensional trait space, which reflects fast or slow rate of return on carbon investment in leaves. These relationships between LES functional traits are strong at global scales and consistent across species and biomes. However, there is evidence that the LES relationships may be weak or absent at smaller scales due to different factors affecting traits locally. 2. Here we quantify: (1) the intraspecific functional trait variation within a model clonal species, Populus tremuloides; (2) how important is microclimate in determining intraspecific trait variation; (3) whether and how much trait-trait, trait-environment relationships in this species are consistent with global interspecific LES patterns; (4) how trait – trait and trait – environment relationships change with ploidy level. We collected leaf functional traits from 15 aspen clones using a hierarchical sampling design along a large environmental gradient in Colorado, we analyzed trait - trait and trait – environment relationships within and across Populus tremuloides genotypes and how these relationships changes with ploidy level. 3. We found: (1) the highest variation within clones, indicating high plasticity; (2) opposite of what we would expect, microclimate was a weak predictor of functional traits (3) trait – trait relationships at the intraspecific scale were not consistent with the LES; (4) we found significant differences in physiology and shifts in resource-use trade-offs in trait – trait and trait – environment relationships for diploids and triploids. 4. Synthesis. We conclude that the LES does not hold at the intraspecific scale for Quaking aspen, meaning that at finer scales there are not strong constraints determining the strategies plants can use. These findings also show that the ploidy level can affect and shift the LES trait – environment relationships and that microenvironment which is thought to be direct driver of trait variation at finer scales, does not predict trait variation at the intraspecific scale for Quaking aspen functional traits. 3 4 Contents Abstract 3

What abiotic and biotic factors predict the shapes of plant diversity-productivity relationships? - F. Vila-Terrad (2018)
Anthropogenic influence over biodiversity has altered ecosystem functions. One important ecosystem function related to diversity is productivity. Plant richness has long been considered for determining productivity. Despite the importance of the relationships between diversity and productivity, their shapes are debated and what determines variation in shapes is not well understood. We examined diversity-productivity relationships from local to landscape scales in a mountain ecosystem. We first asked: what is the shape of the richness and productivity relationship at the landscape? We compared fits of linear and Michaelis-Menten models to richness predictions of productivity. Also, we evaluated whether the humped-back model of productivity and diversity applies in the system. Second, we asked: what abiotic and biotic factors predict the shapes of richness- productivity relationships within sites? We collected plant community composition data including richness and plant cover of each species as a proxy for productivity in 67 sites across 6 peak-valley combinations spanning elevation gradients. Also, abiotic and biotic factors were recorded in all sites. The Michaelis-Menten model was a better predictive fit than the linear model for predicting cover with richness. We found a positive relationship between richness and productivity at landscape scale. But, the saturation curve of the Michaelis-Menten model predicts better the increase of productivity with richness. We found evidence for the humped-back model of productivity and richness across the landscape. Finally, abiotic factors were identified predicting derived parameters beta, Vmax, and K. Importantly, our results suggest that fewer species can make high biomass production with high nitrogen and potassium.

New Players on the Colorado River — the Tribes - Lawrence J. MacDonnell (SSRN Electronic Journal, 2018)

Chemotypic variation in oshá (Ligusticum porteri) in Colorado, USA - L. Lowe; Brittany N. Smith; J. Owens; Emily H Mooney (J Appl. Res. Med. Aromat. Plants, 2018)
Abstract Ligusticum porteri (osha) is an important wild-harvested medicinal plant. Populations of this plant occur in meadows and forest understories in the subalpine and montane zones of the Rocky Mountains. We examined variation in the bioactive compounds of 44 methanolic extracts of L. porteri roots harvested from eleven populations in Colorado, USA during 2012 and 2015. Populations were found in two distinct regions of Colorado, the Front Range and Western Slope. We also classified population light environment as either meadow or understory based on the mean percent of full-sun photosynthetically active radiation above plants. We used high performance liquid chromatography (HPLC) to quantify variation in five secondary metabolites: Z-ligustilide, trans-ferulic acid, (Z/E)-3-butylidenephthalide, isovanillin and elemicin. Variation between sampling years was found for trans-ferulic acid, elemicin and (E)-3-butylidenephthalide. Root extracts from the Front Range had more than double the mean relative concentrations of (Z)-ligustilide than root extracts from plants on the Western Slope of Colorado. Our results demonstrate distinct chemotypes in L. porteri, and this could have therapeutic effects because (Z)-ligustilide is the major bioactive compound in this species.

Shepherding Compact Security Water in the Upper Colorado River Basin - Anne J. Castle; Lawrence J. MacDonnell (SSRN Electronic Journal, 2018)

The East River, Colorado, Watershed: A mountainous community testbed for improving predictive understanding of multiscale hydrological-biogeochemical dynamics - Phuong Tran; Harry Beller; Jillian F. Banfield; Deb Agarwal; Reed M. Maxwell; Tetsu Tokunaga; Heidi Steltzer; Boris Faybishenko; Nicholas J. Bouskill; Eoin L. Brodie; Charuleka Varadharajan; Carl I. Steefel; et al. (Vadose Zone Journal, 2018)
Core Ideas Development of a 300‐km 2 mountainous headwater testbed began in 2016 in the East River. The testbed can be used to explore how watershed changes impact downgradient water availability and quality. System‐of‐system, scale‐adaptive approaches can potentially improve watershed dynamics simulation. We have new approaches to monitor and simulate water partitioning and system responses. The East River watershed has been developed as a “community” testbed. Extreme weather, fires, and land use and climate change are significantly reshaping interactions within watersheds throughout the world. Although hydrological–biogeochemical interactions within watersheds can impact many services valued by society, uncertainty associated with predicting hydrology‐driven biogeochemical watershed dynamics remains high. With an aim to reduce this uncertainty, an approximately 300‐km 2 mountainous headwater observatory has been developed at the East River, CO, watershed of the Upper Colorado River Basin. The site is being used as a testbed for the Department of Energy supported Watershed Function Project and collaborative efforts. Building on insights gained from research at the “sister” Rifle, CO, site, coordinated studies are underway at the East River site to gain a predictive understanding of how the mountainous watershed retains and releases water, nutrients, carbon, and metals. In particular, the project is exploring how early snowmelt, drought, and other disturbances influence hydrological–biogeochemical watershed dynamics at seasonal to decadal timescales. A system‐of‐systems perspective and a scale‐adaptive simulation approach, involving the combined use of archetypal watershed subsystem “intensive sites” are being tested at the site to inform aggregated watershed predictions of downgradient exports. Complementing intensive site hydrological, geochemical, geophysical, microbiological, geological, and vegetation datasets are long‐term, distributed measurement stations and specialized experimental and observational campaigns. Several recent research advances provide insights about the intensive sites as well as aggregated watershed behavior. The East River “community testbed” is currently hosting scientists from more than 30 institutions to advance mountainous watershed methods and understanding.

Comparing Longworth live traps to hair tubes for describing small mammal communities - G. Sandoval (2018)
Ecologists are always interested in studying populations of a certain area. There are many reasons for this, but two reasons include to see the change in distribution over time and because it can help tell about interactions between species. A traditional way of studying small mammal populations that has been commonly used is live trapping. As useful as it has been, live trapping does have some downfalls. It requires handling animals and is time restrictive. An alternate method of collecting small mammal population data has been explored and was tested in this experiment. My results demonstrated that abundance data from hair-tube traps was significantly positively correlated with traditional live-trap mark recapture population estimates. However, hair identification was difficult, so live trapping is still necessary to identify the species.

Factors Controlling Seasonal Groundwater and Solute Flux from Snow-Dominated Basins - L. A. Bearup; Markus Bill; W. S. Brown; Wenming Dong; Kenneth Hurst Williams (Hydrological Processes, 2018)
AbstractCritical zone influences on hydrologic partitioning, subsurface flow paths and reactions along these flow paths dictate the timing and magnitude of groundwater and solute flux to streams. To isolate first‐order controls on seasonal streamflow generation within highly heterogeneous, snow‐dominated basins of the Colorado River, we employ a multivariate statistical approach of end‐member mixing analysis using a suite of daily chemical and isotopic observations. Mixing models are developed across 11 nested basins (0.4 to 85 km2) spanning a gradient of climatological, physical, and geological characteristics. Hydrograph separation using rain, snow, and groundwater as end‐members indicates that seasonal contributions of groundwater to streams is significant. Mean annual groundwater flux ranges from 12% to 33% whereas maximum groundwater contributions of 17% to 50% occur during baseflow. The direct relationship between snow water equivalent and groundwater flux to streams is scale dependent with a trend toward self‐similarity when basins exceed 5.5 km2. We find groundwater recharge increases in basins of high relief and within the upper subalpine where maximum snow accumulation is coincident with reduced conifer cover and lower canopy densities. The mixing model developed for the furthest downstream site did not transfer to upstream basins. The resulting error in predicted stream concentrations points toward weathering reactions as a function of source rock and seasonal shifts in flow path. Additionally, the potential for microbial sulfate reduction in floodplain sediments along a low‐gradient, meandering portion of the river is sufficient to modify hillslope contributions and alter mixing ratios in the analysis. Soil flushing in response to snowmelt is not included as an end‐member but is identified as an important mechanism for release of solutes from these mountainous watersheds. End‐member mixing analysis used in combination with high‐frequency observations reveals important aspects of catchment hydrodynamics across scale.

Rural-to-Urban Water Transfers: Measuring Direct Foregone Benefits of Irrigation Water under Uncertain Water Supplies - R. G. Taylor; Robert A. Young (2018)
Irrigation water from a southeastern Colorado county has been sold to distant municipalities. The county's junior water right delivered limited and uncertain water supplies which were used on relatively poor soils. The ability of water markets to allocate water to the highest-valued use was addressed by assessing the direct foregone benefits of the transfer using deterministic and discrete stochastic sequential (DSSP) programming models. Crop mix predicted by the DSSP followed observed regional patterns. The DSSP was thus used to derive regional water demand from which foregone value was estimated. Direct regional foregone agricultural benefits were relatively low—due to uncertain water supplies and unproductive soils—indicating the market selected a low-valued supply for transfer.

Examining the impact of pollen diet composition on bee development and lifespan - M. McAulay (2018)
Pollen is the sole protein source for most bees and the largest component of their larval diets.

Water in the West : perspectives from an Upper Basin tributary of the Colorado River - Tait James Andersen (BIBSYS Brage (BIBSYS (Norway)), 2018)
This thesis explores two institutional frameworks utilized in the governance of water in the Southwest of the United States through how they deliver, or fail to deliver, complex equity. These are (1) the legal framework and (2) cooperative agreements. This is done through a case study in the Roaring Fork River watershed, a major Upper Basin tributary to the Colorado River, by evaluating how stakeholders and different values of water are recognized and included in decision-making arenas. Stakeholders in the watershed can be positioned into three main groups: (1) agriculturalists, (2) municipalities and (3) environmentalists and recreationalists. I argue that neither institutional framework currently delivers complex equity and that achieving such equity will require changes in the legal framework because cooperative agreements do not tackle the core issues of property rights and compensation and thus, cannot effectively operate outside the legal framework.

Behavioral correlates of innovation success in facultatively social marmots (Marmota flaviventer) - C. A. Wu (2018)
Innovation has transformed ecology and evolution, and understanding behaviors that lead to innovation success can have profound implications and applications in animal populations and human society. In past research, persistence, behavioral selectivity, and neophobia have influenced an individual’s ability to innovate, however the traits that lead to innovation success are not well understood. Exploring these subjects in the socially flexible yellow-bellied marmot can disentangle these factors and reveal which one, if any, influences innovation success. To test innovation correlates in marmots, we will present them with a two-action puzzle box from which they can obtain a food reward, and video their interactions with the box. These videos will be scored for individual behaviors, and the interactions of innovation success, behavioral interactions with the box, and social metrics will be examined. We predict that high degrees of persistence, behavioral selectivity, and neophilia will correlate with innovation success. Previous studies have found correlations between success in novel habitats and innovation success, and because climate change will cause novel habitats, the results of this study can guide conservation management.