Ecological effects of the biocontrol insects, Larinus planus and Rhinocyllus conicus, on native thistles - G. J. Dodge (2005)

Proterozoic tectonic evolution of southern Laurentia: new constraints from field studies and geochronology in southern Colorado and northern New Mexico, U.S.A. - James V. Jones (Texas ScholarWorks (Texas Digital Library), 2005)
patient instruction by Kathy Manser in the U-Pb lab

Factors affecting male song evolution in Drosophila montana - D. Mazzi; K. Klappert; A. Hoikkala (Current topics in Developmental Biology, 2005)

the influence of red-naped sapsuckers on willow bird communities - E. C. Clark (2005)
In subalpine Colorado ecosystems, red-naped sapsuckers feed by excavating sap wells in shrubby willow branches. Many species of insects, birds, and mammals are known to feed from this sap. Previous studies on avian sap robbers suggest these sap wells may have a direct effect on bird communities. Furthermore, studies on the effects of yellow-bellied sapsucker sap wells on insect guilds suggest that sap wells may influence bird distribution indirectly through their influence on insect abundance. In this study, I investigated the relationship between sap wells and bird diversity. I found no effect of sap wells on bird diversity or on known avian sap robbers; however, other variables, such as drainage and proximity to a river, were found to affect bird diversity.

Effects of Interspecific Pollen Transfer (IPT) in a Specialist and a Generalist Flower - C. D. Muir (2005)

Tree-Ring Resources of the Rocky Mountain Biological Laboratory - Christopher Still; John Harte (2005)

The effects of the invasive plant Linaria vulgaris on native plant fitness and pollinator behavior - S. Lei (2005)
The invasion of the European perennial Linaria vulgaris to the alpine environment of Colorado may lead to competition for natural resources, space, and pollinators with native species. I measured the effects on fitness of L. vulgaris on three plant species native to Colorado, using both hand-pollination and controls to assess pollen limitation of seed set; plant size was measured for analysis as well, using root stalk diameter of Ipomopsis aggregata and number of flowering stalks of Linum lewisii and Potentilla pulcherrima, in the presence and absence of L. vulgaris. I also recorded pollinator visitations to my focal plants. The fruits for each plant were collected as they matured, and the number of aborted fruits were collected and recorded as well. The number of seeds was counted for each plant per collection day, as fruits often dehisced in the envelopes used to collect them. Analyses of plant size and mean floral display showed no significant difference in the presence of L. vulgaris as compared to its absence. These preliminary results suggest that L. vulgaris does not affect plant size or floral display in these three species.

GPS/GIS Systems Analysis: Recommendations and suggestions for the future - J. V. Abraham (2005)

Cytoplasmic and nuclear markers reveal contrasting patterns of spatial genetic structure in a natural Ipomopsis hybrid zone - C. A. Wu; Diane R. Campbell (Molecular Ecology, 2005)

Conservation and Status of North American Amphibians - Howard Whiteman; S. A. Wissinger (2005)

Nectar robbing in Ipomopsis aggregata: does high nectar production confer tolerance? - M. L. McCutcheon (2005)

Developmental Thresholds, Life History Trade-Offs, and Resource Allocation in Wetland Caddisflies (Trichoptera) - J. E. Jannot (2005)

The effects of Castilleja miniata's parasitic relationship with Delphinium nuttallianum on pollinator visitation and pollination success - J. C. Brennan (2005)
Castilleja miniata is a hemiparasite capable of taking up chemical toxins from its host plant. A unique relationship is C. miniata’s parasitism on Delphinium nuttallianum (which contains alkaloids); alkaloids from D. nuttallianum are taken up into C. miniata’s nectar which could negatively affect C. miniata’s pollinator visitation when compared to C. miniata parasitizing other plants. However, D. nuttallianum may have an increased visitation when parasitized by C. miniata should the pollinators prefer the alkaloid free nectar of the close-by D. nuttallianum over the alkaloid-containing nectar of its host. I observed pollinator visitation to two groups of C. miniata (one parasitizing D. nuttallianum and one not) and two groups of D. nuttallianum (one being parasitized by C. miniata and one not) for a total of eighty hours and performed herbivory assessments and hand-pollinations. I also assessed seed set for all treatments to determine if pollinator visitation dictated pollination success. There were no significant differences in flowers probed/open ratios or total visitation between C. miniata treatments or D. nuttallianum treatments, although the trends were in the direction expected for C. miniata (decreased visitation to C. miniata parasitizing D. nuttallianum) but not for D. nuttallianum (decreased visitation to D. nuttallianum parasitized by C. miniata). D. nuttallianum seed number and seed weight did not support pollination visitation determining pollination success; both seed number per plant and seed weight per plant negatively correlated with number of visits. C. miniata seed data has not yet been determined.

Global change and mountain regions - John Harte (2005)

Within- and between-pond differences in diapausing egg production in Leptodiaptomus coloradensis (Copepoda: Calanoida) - E. J. Maly (Verh. International Verein. Limnology, 2005)

Effects of nectar robbing on nectar dynamics and bumblebee foraging strategies in Linaria vulgaris - James D. Thomson (Oikos, 2005)

Efficient harvesting of renewing resources - K. Ohashi; James D. Thomson (Behavioral Ecology, 2005)
Many foraging animals return to feeding sites to harvest replenishing resources, but little is known about efficient tactics for doing this. Can animals with adequate cognitive abilities increase their efficiency by modifying their behavior according to memories of past experience at particular sites? We developed a simulation model of animals harvesting renewable resources from isolated patches in undefended, competitive situations. We compared four foraging tactics: (1) moving stochastically without using any information from past experiences (random searching); (2) moving stochastically, but going longer distances after encountering lower reward (area-restricted searching); (3) repeatedly moving along a fixed route (complete traplining); and (4) traplining, but sampling and shifting to neighboring rewarding patches after encountering low reward (sample-and-shift traplining). Following Possingham, we tracked both the resources actually harvested by a focal forager (i.e., rewards) and the standing crops of resources that accumulated at patches. Complete traplining always produces less variation in elapsed time between visits than random searching or area-restricted searching, which has three benefits: increasing the reward crop harvested, if resource renews nonlinearly; reducing resource standing crop in patches; and reducing variation in reward crop per patch. Moreover, the systematic revisitation schedule produced by complete traplining makes it more competitive, regardless of resource renewal schedule or competitor frequency. By responding to their past experiences, using sample-and-shift traplining, foragers benefit only when many patches are left unvisited in the habitat. Otherwise, the exploratory component of sample-and-shift traplining, which increases the movement distance and the variation in elapsed time between visits, makes it more costly than complete traplining. Thus, traplining will usually be beneficial, but foragers should switch between “impatient” (sample-and-shift traplining) and “tenacious” (complete traplining) traplining, according to temporal changes in surrounding situations.

The Timing of Floral Color Change in Lupinus argenteus - L. Braucher (2005)
This paper describes the timing of floral color change with Lupinus argenteus and the behavior of pollinator visitation to manipulated treatments. In theory plants my benefit from color change in two ways. One way is to direct pollinators to rewarding flowers. This may increase the foraging efficiency of the pollinators with the result that before leaving the plant, more flowers are visited. A second benefit plants may get is the prevention of pollen waste on unreceptive stigmas by directing pollinators to receptive flowers (Gori 1989). Floral color changes with un-manipulated (un-pollinated) controls were compared in terms of the rate of color change to hand-pollinated treatments. Three stages of color were used to asses each stage of change. Field comparisons on 30 inflorescences (15 treatments and 15 controls) revealed that treatments moved to stage two twice as fast than controls but stayed longer in stage two than controls. Pollinator visitation behavior was observed by painting the banner spot purple (the last color stage) on young flowers that contained pollen. I also painted white spots as a control. My hypothesis assumed that pollinators would avoid the painted purple spots since the purple stage is a cue to pollinators that less pollen exists (Gori 1989). Herbivory was responsible for the loss of pollinator visitation data. I returned to the field sites to find insects inside the netted plant bags along with damage to the painted petals. 95% of pollinator visits were to natural white spotted flowers.

Consistency of individual foraging and vigilance patterns in Yellow-Bellied marmots - R. J. Trojan (2005)
Animals frequently exhibit variation in their behavior. In the past this variation has been treated as statistical error, but research has identified correlated behaviors across contexts, referred to as behavioral syndromes. We focused on yellow-bellied marmots (Marmota flaviventris) and examined vigilance and foraging patterns while in five different contexts: food alone, food in the presence of a mirror, food in the presence of a plastic Canada goose decoy, foraging on natural vegetation, and behavior while in a trap. We found correlations in how animals foraged across some of these different contexts. Thus, we discovered that a ‘vigilance while foraging’ syndrome exists in a natural population of marmots. We found that there are contextually linked groups of behavior that explain variation in behavior within a population of animals, and further research needs to be done to analyze the fitness consequences of this syndrome.

Intraspecific variation in marmots - Kenneth B. Armitage (Contribuciones Mastozoologicas en Homenaje a Bernarda Villa, 2005)

Importance of Fertilization of Host Plants to Ant Tending and Growth Rates in Glaucopysche lygadmus (Lepidoptera: Lycaenidae) - Robert Z. Brown; J. S. Reithel; Ian Billick (Annals of the Entomological Society of America, 2005)

Evolutionary ecology of facultative paedomorphosis in news and salamanders - P. Joly; M. Denoel; Howard Whiteman (Biological Reviews, 2005)
Facultative paedomorphosis is an environmentally induced polymorphism that results in the coexistence of mature, gilled, and fully aquatic paedomorphic adults and transformed, terrestrial, metamorphic adults in the same population. This polymorphism has been of interest to scientists for decades because it occurs in a large number of caudate amphibian taxa as well as in a large diversity of habitats. Numerous experimental and observational studies have been conducted to explain the proximate and ultimate factors aﬀecting these heterochronic variants in natural populations. The production of each alternative phenotype is based on a genotyperenvironment interaction and research suggests that diﬀerences in the environment can produce paedomorphs through several ontogenetic pathways. No single advantage accounts for the maintenance of this polymorphism. Rather, the interplay of diﬀerent costs and beneﬁts explains the success of the polyphenism across variable environments. Facultative paedomorphosis allows individuals to cope with habitat variation, to take advantage of environmental heterogeneity in the presence of open niches, and to increase their ﬁtness. This process is expected to constitute a ﬁrst step towards speciation events, and is also an example of biodiversity at the intraspeciﬁc level. The facultative paedomorphosis system is thus ripe for future studies encompassing ecology, evolution, behaviour, endocrinology, physiology, and conservation biology. Few other systems have been broad enough to provide varied research opportunities on topics as diverse as phenotypic plasticity, speciation, mating behaviour, and hormonal regulation of morphology. Further research on facultative paedomorphosis will provide needed insight into these and other important questions facing biologists.

Are populations of mayflies living in adjacent fish and fishless streams genetically differentiated? - P. B. Mather; John M. Hughes; M. Hillyer; Andrea Encalada; B. L. Peckarsky (Freshwater Biology, 2005)

Status and Conservation of US Amphibians. Vol 1: Conservation Essays - E. Muths; C. Carey; M. Tildon Jones; L. J. Livo; P. S. Corn; C. W. Loeffler (2005)

Foraging Differences Between Sexes in Ambystoma tigrinum nebulosum - B. Wallace; Jacqueline Doyle; Howard Whiteman (2005)
Many studies have looked at intraspecific competition between larva and adults, paedmorphic and metamorphic Ambystoma tigrinum. None, however, none have looked at male vs. female competition. In this experiment, twelve females and twelve male tiger salamanders were observed foraging for caddisfly larva and snails. We used six females and six males for each trail. There were no significant differences in foraging efficiency between sexes, although body condition was significantly higher for females. Females may therefore be maximizing body size through other methods, or may forage more efficiently for prey types not used in this study.

Impacts of Mule Deer Herbivory on Herbaceous Vegetation in the Gothic Area, with Focus on Aquilegia coerulea - R. Arozqueta (2005)
The impacts of growing deer populations upon biodiversity have caused concern for ecologists since it is speculated that certain species of herbs are targeted and over abundantly browsed. This study investigated deer abundance as well as intensity of deer browsing of herbaceous plants inside and outside the fenced protection of the Rocky Mountain Biological Laboratory. Aquilegia coerulea was used as a focal species since it has been observed to be very highly browsed. It was found that deer are observed more often inside the fence than out. Overall browsing intensity of all plant species in sites inside and outside the fence was not significantly different; however variation between sites in meadows as opposed to aspen forests was significant. Across all study sites, Aquilegia coerulea was on the average browsed 50%. Significant differences were found between Aquilegia plants caged to prevent herbivory and those open to browsing; unprotected plants produced one-third of the normal fruit production of protected plants.

Yellow-bellied marmot hiding time is sensitive to variation in costs - D. Pelletier; Daniel T. Blumstein (Canadian Journal of Zoology, 2005)
Many species use refugia to avoid predators, but remaining in a refuge is costly because foraging and engaging in other beneficial activities are curtailed while in a refuge. Thus, we expect that the duration of refuge use will be optimized. We tested a key prediction of this optimization hypothesis in yellow-bellied marmots, Marmota flaviventris (Audubon and Bachman, 1841), by providing supplemental food next to their burrows to manipulate the costs of remaining in a refuge. We then systematically walked towards a subject that was foraging on supplementary food or a subject that was not foraging on supplementary food until the individual disappeared into its burrow. We found a significant effect of our feeding treatment; subjects with supplementary food emerged from their burrows sooner than those without it. We also found a complex interaction between our feeding treatment and immergence distance (i.e., the distance subjects were at when they disappeared into their burrows). Individuals that tolerated close approaches emerged sooner when food was present, while those that were intolerant of approaching humans took longer to emerge and emerged sooner when food was not present. Juveniles emerged significantly sooner than adults, while there was no detectable difference between emergence times for adults and yearlings. This is the first demonstration in a mammal that hiding time is sensitive to the cost of remaining in the burrow. A number of previous studies on hiding times have focused on ectothermic species. More generally, our results suggest that endotherms are also likely to optimize the time that they remain in a refuge.

Variation in frequency of hybrids and spatial structure among Ipomopsis (Polemoniaceae) contact sites - George Aldridge (New Phytologist, 2005)

Comparing prezygotic isolating mechanisms in unimodal and bimodal plant hybrid zones - George Aldridge (2005)

Temporal and spatial variation in pollination of a montane herb: a seven-year study - Alison K. Brody; Mary V. Price; Nickolas M. Waser; Diane R. Campbell; Rebecca E. Irwin (Ecology, 2005)
Pollination by animals is critical to sexual reproduction of most angiosperms. However, little is known about variation in pollination service to single plant species. We report results of a long-term study of Ipomopsis aggregata, a semelparous montane herb whose flowers are visited by hummingbird and insect pollinators as well as “floral larcenists.” We censused flower visitors over seven summers at permanent study sites separated by several hundred meters, and counted pollen delivered to flowers on a subset of plants observed for visitation. The species composition of the community of visitors varied significantly across years and within the flowering season; sites varied significantly only in the magnitude of parallel annual changes in the visitor community. Rates of flower visitation fluctuated over an order of magnitude or more. Variation in mean stigma pollen load among plants flowering in the same site and year was explained by a causal path model in which visitation rates by pollinators and larcenists had linear positive and negative effects, respectively. A simplified model including only pollinators explained almost as much variance as did the full model. However, qualitatively different parameter estimates were produced by an analogous causal model based on population means across site–year combinations. Discrepant results from within- and between-population levels of analysis suggest that pollen receipt is influenced by environmental factors that vary among sites and years, as well as by pollinator visit rates. We present a heuristic causal model that includes such factors, and we note its implications for ecological and evolutionary studies of pollination.

A reconnaissance of population genetic variation in artic and subarctic sulfur butterflies (Colias spp.; Lepidopetera, Pieridae) - C. L. Boutwell; C. W. Wheat; W. B. Watt (Canadian Journal of Zoology, 2005)

Genetic and ecophysiological consequences of natural hybridization between Ipomopsis aggregata and I. tenuituba - C. A. Wu (2005)

Intraspecific signaling function of Crown Coloration in Mountain White-Crowned Sparrows - D. Cohen (2005)
There is evidence showing that large differences between age/sex categories in crown morphology of white-crowned sparrows are used to signal status. We investigated the role of more subtle crown characteristics, specifically the proportion of the crown that is white, as a signal used to mediate aggression. The response of resident white-crowned sparrows was measured when decoys with experimentally altered crowns were placed on their territory. We found significant differences between a large and small proportion white decoy treatments when the birds were still nesting early in the season, suggesting proportion white is used as a signal in this system. However, we found no significant results later in the season or when all the trials were analyzed as a whole, suggesting a strong seasonality effect in the responsiveness of the birds.

Antipredatory response of mule deer (Odocoileus hemionus) to predator urines - T. N. Lee (2005)
Auditory, visual, and olfactory cues of predator presence create a landscape of fear for prey animals. Prey can respond to predation risk perceived from these cues by increasing vigilance, increasing group size, altering habitat use, and reducing activity times. State of the animal and predator type may influence the antipredatory response(s) an animal adopts. I presented mule deer (Odocoileus hemionus) with control, coyote, and mountain lion urine cues in their foraging meadows. Deer responded to predator urine cues to reduce predation risk by increasing vigilance frequency and changing their distance to the edge of the forest based on the different predators represented. State of the animal influenced the responses to predator urine cues. This study demonstrates that Odocoileus hemionus use predator urine cues as an indication of predation risk in the landscape of fear they live in.

A phenological mid-domain effect in flowering diversity - M. A. Morales; G. J. Dodge; David W. Inouye (Oecologia, 2005)

The amino acids used in reproduction by butterflies: a comparative study of dietary sources using compound specific stable isotope analysis - D. M. O'Brien; M. L. Fogel; Carol L. Boggs (Physiological and Biochemical Zoology, 2005)

Weather influences on demography of the yellow-bellied marmot (Marmota flaviventris) - O. A. Schwartz; Kenneth B. Armitage (Journal of Zoology, London, 2005)
Yellow-bellied marmots Marmota flaviventris were live-trapped and marked in the East River Valley of Colorado from 1962 to 1998. For females, static life tables were calculated each year from 1967, when ages were well known, to 1997. Population density was determined, and from life tables calculations were made of: survivorship of young, yearlings and adults; percentage of females producing litters; mean and variance of litter size; net reproductive rate (Ro ); and generation length. From climate records a set of 14 annual weather variables was developed that described temperature, precipitation and lengths of growing season and winter. Data from 1981 and 1996 were not used since weather data contained extreme outliers in date of last snow cover. Univariate correlation matrices were calculated among weather variables, among demographic variables, and between weather and demographic variables. Mean temperature in 24 of 29 years was cooler than long-term average temperature. Generation length increased during the years of the study. Weather data were used as independent variables with each dependent demographic variable to calculate nine multiple correlation and regression models. Models explained from 0% to 58% of the variation in demography. Significant factors in each model were mostly interpreted as affecting availability of energy necessary for successful hibernation and reproduction. Key words: demography, Marmota flaviventris, marmot, weather, correlation

Effects of climate change on growth and seedling establishment of young lodgepole pine - T. A. Perkins (2005)
Anthropogenically induced climate change is expected to effect numerous climatic alterations pertinent to ecosystems, including increased mean global temperature and altered precipitation regimes. High-elevation ecosystems are especially sensitive to climatic changes because slight fluctuations in factors like snowmelt date and soil moisture can lead to major changes in the length of growing season and other factors. Two five-year periods with contrasting climate factors in Gunnison Co. Colorado provided an opportunity to study the impacts of climate change on high-elevation ecosystems. I studied the relative influence of those two periods on six stands of young lodgepole pine and found that warming-associated climate factors enhanced growth in young trees and had little effect on seedling establishment success. These findings corroborate ecophysiological knowledge about lodgepole pine and suggest a possible shift in forest composition and distribution under climate change scenarios.

Ecologia de los rios temporales de la isla de Mallorca - M. Alvarez (2004)

Making eggs from nectar: Connections between butterfly life history and the importance of nectar carbon in reproduction - M. L. Fogel; D. M. O'Brien; Carol L. Boggs (Oikos, 2004)

Invasive Linaria vulgaris, disturbance, and diversity: associations at multiple spatial scales in Colorado - K. M. Bovee (2004)

Effects of snowmelt timing and neighbor density on the distribution of the high altitude plant, Potentilla diversifolia - K. A. Stinson (Arctic, Antarctic and Alpine Research, 2004)

Metabolic diversity in yellow-bellied marmots - Kenneth B. Armitage (Life in the cold: evolution, mechanisms, adaptation: Twelfth international hibernation symposium, 2004)

Red-naped Sapsucker nest tree selection and effects on the willow breeding bird community - T. Cody (2004)
The Red-naped sapsucker creates a nest cavity in aspen woodlands each year, required by other bird spp. for nesting, and spends much of its foraging time in willow wetlands. This study attempted to determine a) how does proximity of potential nest trees to forest edge and willows affect the sapsucker’s choice of nest tree b) is there an edge effect on insect abundance and c) what are the effects of sapsucker presence on the willow breeding bird community? Sapsucker nest trees are significantly closer to the edge of the forest than unoccupied trees, but not closer to willows. Insect abundance increases towards the forest edge; this could help explain the preference for sapsucker edge- nesting. An increased density of sapsucker-drilled sap wells in the willows acts to increase willow breeding bird diversity.

Temperature regulation in burying beetles (Nicrophorus spp.: Coleoptera: Silphidae): effects of body size, morphology and environmental temperature - M. J. Merrick; Richard Alexander Smith (The Journal of Experimental Biology, 2004)

Natural selection favors rapid reproductive phenology in Potentilla pulcherrima (Rosaceae) at opposite ends of a subalpine snowmelt gradient - K. A. Stinson (American Journal of Botany, 2004)

Development to diapause in a population of Euphydryas gillettii (Nymphalidae): effects of egg cluster size and habitat parameters - J. Carrillo (2004)
I studied survivorship from the period of egg laying to winter diapause in a population of E. gillettii (Nymphalidae). I investigated if fitness, in the context of hatching and succesful development to diapause was related to egg cluster size, habitat parameters, or both, and if there were factors affecting egg cluster size. Results indicate that hatching is affected by sun exoposure of the egg cluster and predation risk and soil condition of the host plant. Egg cluster size had no affect hatching. This suggests that there is no optimal cluster size that increases fitness of the eggs; clusters are susceptible to equal amounts of mortality regardless of their size. Post-hatching fitness remains to be determined. Egg cluster size was related to its sun exposure and the number of egg layers in the cluster. Faster development occured for egg masses laid in one layer on plants with a low predation risk and dry soil conditions.

Encyclopedia of animal behavior - Kenneth B. Armitage (2004)

Evolutionary genetics of dorsal wing color in Colias butterflies - J. Ellers; Carol L. Boggs (Journal of Evolutionary Biology, 2004)

The effect of food quality and time constraints on caddisfly growth and development - M. Ruck (2004)
The fitness of the non-feeding adult caddisfly, Asynarchus nigriculus is largely dependent on the accumulation of nutrients during its larval stage. The energy obtained during this time is then allocated into growth and development for the adult insect. This allocation of energy may be constrained by drying time of the temporary waters the larvae inhabit. We measured the effect of food quality and drying time on survivorship, time to pupation, environmental variables, larval aggression, and the sizes of adult body parts. The results suggest that low food treatments provoke higher larval aggression and cannibalism, thus lower survivorship than high food treatments. Temporary water treatments resulted in earlier pupation than permanent treatments suggesting that the larvae increased their rate of development in order to emerge as adults before their habitat dried. Surprisingly, increased food quality did not result in larger or heavier adults, but did affect male wing lengths. Allocation to certain body parts such as the wings, suggest that food quality may be important for the adults’ fitness.

Climate change and extinction risk - A. Ostling; A. P. Kinzig; James Aaron Green; John Harte (Nature, 2004)
The overall conclusion, that a large fraction of extant species could be driven to extinction by expected climate trends over the next 50 years, is compelling: it adds to the many other reasons why new energy policies are needed to reduce the pace of warming.

Reliability and the adaptive utility of discrimination among alarm callers - L. Verneyre; J. C. Daniel; Daniel T. Blumstein (Proceedings of the Royal Society of London B, 2004)
Unlike individually distinctive contact calls, or calls that aid in the recognition of young by their parents, the function or functions of individually distinctive alarm calls is less obvious. We conducted three experiments to study the importance of caller reliability in explaining individual-discriminative abilities in the alarm calls of yellow-bellied marmots (Marmota flaviventris). In our first two experiments, we found that calls from less reliable individuals and calls from individuals calling from a greater simulated distance were more evocative than calls from reliable individuals or nearby callers. These results are consistent with the hypothesis that marmots assess the reliability of callers to help them decide how much time to allocate to independent vigilance. The third experiment demonstrated that the number of callers influenced responsiveness, probably because situations where more than a single caller calls, are those when there is certain to be a predator present. Taken together, the results from all three experiments demonstrate the importance of reliability in explaining individual discrimination abilities in yellow-bellied marmots. Marmots' assessment of reliability acts by influencing the time allocated to individual assessment and thus the time not allocated to other activities.

Declining Amphibians: A United States' Response to the Global Problem - Howard Whiteman; S. A. Wissinger (2004)

Badger predation on yellow-bellied marmots - Kenneth B. Armitage (American Midland Naturalist, 2004)
Badger (Taxidea taxus) activity was recorded in colonies of yellow-bellied marmots (Marmota flaviventris) during behavioral observations and trapping. Badgers were observed seven times in a marmot colony and extensive digging at marmot burrows was recorded five times in 40 y. When four badgers occupied a burrow at the edge of a marmot colony, the behavior of marmots and badgers was observed for 7 d and the marmots for an additional 6 d after the badgers departed. Badgers hunted at a significantly higher rate in the afternoon than in the morning. The adult female usually hunted alone, failed to capture any adult marmots, but did kill young marmots. When badgers were present, marmots had more frequent alarm calls, lower rates of foraging and higher rates of vigilance than when badgers were absent. I estimated that badgers killed 67 of 1423 individual marmots. The risk of being killed by a badger was highest for young, intermediate for yearlings and lowest for adults. Badgers probably have little impact on marmot demography except for localized, short-term increases in mortality, but may significantly affect the fitness of individual marmots.

Dead wood biomass and turnover time, measured by radiocarbon, along a subalpine elevation gradient - P. Baer; J. Southon; L. M. Kueppers; John Harte (Oecologia, 2004)
Differences in biomass and decay rates along the elevation gradient suggest that climate warming will lead to a loss of dead wood carbon from subalpine forest.

Direct and indirect effects of pollinators and seed predators to selection on plant and floral traits - A. vonderOhe; L. Garcia-Mayeya; D. Cariveau; Alison K. Brody; Rebecca E. Irwin (Oikos, 2004)
Although flowering traits are often assumed to be under strong selection by pollinators, significant variation in such traits remains the norm for most plant species. Thus, it is likely that the interactions among plants, mutualists, and other selective agents, such as antagonists, ultimately shape the evolution of floral and flowering traits. We examined the importance of pollination vs pre‐dispersal seed predation to selection on plant and floral characters via female plant‐reproductive success in Castilleja linariaefolia (Scrophulariaceae). C. linariaefolia is pollinated by hummingbirds and experiences high levels of pre‐dispersal seed predation by plume moth and fly larvae in the Rocky Mountains of Colorado, USA, where this work was conducted. We first examined whether female reproduction in C. linariaefolia was limited by pollination. Supplemental pollination only marginally increased components of female reproduction, likely because seed predation masked, in part, the beneficial effects of pollen addition. In unmanipulated populations, we measured calyx length, flower production, and plant height and used path analysis combined with structural equation modeling to quantify their importance to relative seed set through pathways involving pollination vs seed predation. We found that the strength of selection on calyx length, flower production, and plant height was greater for seed predation pathways than for pollination pathways, and one character, calyx length, experienced opposing selection via pollination vs seed predation. These results suggest that the remarkable intraspecific variation in plant and floral characters exhibited by some flowering plants is likely the result of selection driven, at least in part, by pollinators in concert with antagonists, such as pre‐dispersal seed predators. This work highlights the subtle but complex interactions that shape floral and vegetative design in natural ecosystems.

Colorado River Delta - JEFFREY P. COHN (BioScience, 2004)

Community and evolutionary ecology of nectar. - Anurag A Agrawal; L. S. Adler; Rebecca E. Irwin (Ecology, 2004)

What is the nature of the ant-aphid relationship? - S. Hammer (2004)
Many aphid species, on a wide variety of plants, are tended by ants. We tested whether the relationship between the ant species Formica obscuripes and an aphid species on rabbitbrush (Chrysothamnus viscidiflorus) was a mutualism and, if so, whether it was obligate or facultative. Using a fully factorial design, we measured the response of aphid numbers to the presence and absence of ants and predators, resulting in four treatments. We found that the aphid numbers were lower in the presence of ants and about equal regardless of the presence or absence of predators. For two out of the three surveys, aphid numbers were highest in the absence of both ants and predators. In the absence of ants and the presence of predators, aphid numbers were intermediate. We conclude that there is no ant-aphid mutualism in this system.

Do yellow-bellied marmots respond to predator vocalisations? - L. Cooley (2004)

Yellow-bellied marmots discriminate between the alarm calls of individuals and are more responsive to calls from juveniles - J. C. Daniel; Daniel T. Blumstein (Animal Behaviour, 2004)
It is shown that individuals are able to identify when young, and presumably vulnerable, marmots are calling, and to respond by engaging in vigilance and to discriminate between at least one broad age–sex category.

Convergence across biomes to a common rain-use efficiency - Stephen A. Smith; S. Schwinning; T. Huxman; P. Fay; B. Haddad; M. R. Shaw; G. Koch; O. Sala; W. Pockman; J. Zak; D. Tissue; J. Weltzin; et al. (Nature, 2004)
It is shown that RUE decreases across biomes as mean annual precipitation increases, and during the driest years at each site, there is convergence to a common maximum RUE (RUEmax) that is typical of arid ecosystems.

Avian Diversity in Aspen and Conifer Forests : - S. Steckler (2004)
In order to compare avian diversity (species richness and evenness) between aspen and conifer forest communities in Gothic, Colorado, point counts were conducted in three replicates of each habitat type. Additionally, tree density and light measurements were performed as a measure of structural complexity. Aspen plots had higher tree densities and lower incident light through the forest canopy compared with conifer plots. Twenty-two bird species were identified in the surveys, and aspen sites had a slightly higher number of species (n=18) than their coniferous counterparts (n=16). Conifer stands had a marginally higher abundance of birds, however. A

Functional ecological implications of intraspecific differences in wing melanization in Colias butterflies - J. Ellers; Carol L. Boggs (Biological Journal of the Linnean Society, 2004)
Variation in the degree of insect wing melanin affects thermoregulation, and is expected to be adapted to local environmental conditions, for example over an elevational gradient. The effects of melanization on flight activity and egg maturation rate were assessed in the closely related butterflies Colias philodice eriphyle and C. eurytheme using experimental manipulation of wing darkness and transplant experiments between high and low elevation sites. Experimental manipulation of wing darkness in C. p. eriphyle demonstrated that light males had reduced flight activity at high elevations, and darkened males had reduced flight activity at low elevations. In contrast, the transplant experiments revealed asymmetrical adaptation for male C. p. eriphyle. At high elevations darker, high-elevation males had higher flight activity than lighter, low-elevation males, but there was no difference between the two groups at low elevation. For females, melanization had no effect on flight activity. However, an increase in female C. eurytheme wing darkness led to a significantly higher egg maturation rate at cold ambient temperatures, which may increase female reproductive output under natural conditions. Therefore, dispersers moving down in elevation may be more successful than those moving up. © 2004 The Linnean Society of London.

THE PERSISTENCE OF QUAKING ASPEN (POPULUS TREMULOIDES) IN THE GRAND MESA AREA, COLORADO - Thomas T. Veblen; Sarah Drinkwater; Dominik Kulakowski (Ecological Applications, 2004)
Human activities have caused the decline of numerous species and ecosystems. To promote ecosystem resilience, recent management efforts aim to maintain ecosystem patterns and processes within their historical range of variability. There has been substantial concern that quaking aspen, the most widely distributed tree in North America and the most important deciduous tree in the subalpine forests of the Rocky Mountains, has declined significantly in the western landscape during the 20th century. This reported decline has been attributed to conifer encroachment associated with fire exclusion, as well as other causes. To assess long‐term changes in the extent of quaking aspen in a 175 000‐ha study area in western Colorado, we used a Geographic Information System to compare an 1898 map of vegetation and fires to a modern map of present forest cover types. Based on this comparison, a larger portion of the current landscape is dominated by quaking aspen relative to the late 19th century, a period of extensive burning in this area. During the 20th century, aspen was persistent over most of its extent, even in the absence of fire. Fires of the late 19th century also increased aspen cover in stands that were previously dominated by spruce and fir. The trend toward increased aspen was greater at lower elevations. The total area where spruce and fir have replaced aspen is small in comparison to the area where aspen has increased or has persisted. The successional replacement of aspen by conifers is more pronounced at higher elevations and where the predisturbance vegetation was dominated by conifers. The net effect of severe disturbances during and after the late 19th century has also increased aspen cover relative to the period that preceded these disturbances. Thus, where the successional replacement of aspen by conifers is occurring today, such a trend may be within the range of historical variation. Long intervals between large, severe natural disturbances in ecosystems can result in a broad range of natural ecological conditions, including dominance by particular species.

Resource specialization in puddling Lepidoptera - B. Dau; Carol L. Boggs (Enivornmental Entomology, 2004)
Lepidoptera feed at mud puddles, dung, and carrion in a behavior known as puddling. Sodium and sometimes protein are feeding cues, are actively collected, and play a potentially important role in lepidopteran nutritional and mating ecology. We showed that montane butterfly species have feeding preferences among mud, herbivore dung, and carnivore dung, and that these preferences differed among butterfly species. The puddling substrates varied in soluble sodium content, with mud having the lowest concentrations and carnivore dung having the highest. Within one species, Pieris napi L., visit frequencies to mud versus dung matched visit frequencies to sand trays filled with sodium solutions matching the concentrations seen in mud or dung. This suggests that the preference hierarchy of this species is driven by soluble sodium concentration. Overall, the results indicate that lepidopteran species specialize on different puddling substrates, likely obtaining different arrays of nutrients. This suggests that there are species- or family-specific roles for puddling nutrients in the overall nutrient budget of the insects.

Does pollination limit tolerance to browsing in Ipomopsis aggregata? - K. E. Sharaf; Mary V. Price (Oecologia, 2004)

The structure of plant-pollinator interactions in montane meadow environments - R. Alarcon (2004)

Patterns, mechanisms and consequences to population dynamics (Ephemeroptera: Baetidae) - Andrea Encalada (2004)

The role of larval cases in reducing aggression and cannibalism among caddisflies in temporary wetlands - C. Eldmire; J. C. Whissel; S. A. Wissinger (Wetlands, 2004)

Prehistoric Culture Change on the Colorado Plateau: Ten Thousand Years on Black Mesa. Shirley Powell and Francis E. Smiley, editors. 2002. University of Arizona Press, Tucson, xi + 221 pp. $50.00 (cloth), ISBN 0-8165-1439-9. - Sarah W. Neusius (American Antiquity, 2004)
Prehistoric Culture Change on the Colorado Plateau: Ten Thousand Years on Black Mesa. Shirley Powell and Francis E. Smiley, editors. 2002. University of Arizona Press, Tucson, xi + 221 pp. $50.00 (cloth), ISBN 0-8165-1439-9. - Volume 69 Issue 1

In situ photosynthetic freezing tolerance for plants exposed to a global warming manipulation in the Rocky Mountains, Colorado, USA - T. Huxman; M. E. Loik; Christopher Still; John Harte (New Phytologist, 2004)
• This research tested the hypothesis that experimental infrared warming will reduce photosynthesis for the evergreen shrub Artemisia tridentata and the subalpine, herbaceous Erythronium grandiflorum exposed to an in situ experimental freezing event during the spring snowmelt period. • Photosynthetic tolerance of freezing was measured for plants growing under infrared (IR) warming at 3050 m in the Rocky Mountains, Colorado, USA. In situ freezing was imposed using cold nitrogen gas (from a pressurized container of liquid nitrogen) passed through a heat exchanger placed on top of stems and leaves. • Plant water potential, photosynthetic CO2 assimilation, and stomatal conductance to water vapor were higher for both species on IR-warmed compared with control plots. For A. tridentata, IR warming caused enhanced tolerance of in situ freezing temperatures. There was no difference in freezing tolerance for E. grandiflorum on control vs IR plots. • These results suggest that some species will not be negatively affected by freezing, whereas others may exhibit enhanced tolerance of subzero air temperatures, under a future warmer climate in which snowmelt occurs earlier in the year.

Yellow-bellied marmot population dynamics: demographic mechanisms of growth and decline - Kenneth B. Armitage (Ecology, 2004)
Multiple environmental factors may act synergistically to influence demographic characteristics, and ultimately the dynamics, of biological populations. Using prospective and retrospective analyses of demographic data from a 40-year study of individually marked animals, we investigated the demographic mechanisms of the temporal and spatial dynamics of a yellow-bellied marmot (Marmota flaviventris) population. Prospective elasticity analyses indicated juvenile survival (Pj) would have the largest relative influence on the projected population growth rate (λ). Relative magnitudes of elasticities did not differ between years characterized by positive (λ > 1.0) and negative (λ < 1.0) population growth. However, retrospective analyses of a life table response experiment (LTRE) revealed that changes in fertility (F), followed by age of first reproduction (α) made the largest contributions to observed annual changes in λ. Changes in F and α made the largest contributions to annual declines in λ, whereas changes in Pj also were important to cause increases in λ. Population dynamic differences among marmot colonies were due primarily to spatial variations in α and Pj. Our results indicate that changes in reproductive parameters (α and F) primarily drive the temporal dynamics of our study population, and that demographic mechanisms of population increases might differ from those of population declines. Studies of the regulation of yellow-bellied marmot populations should focus on the factors or processes influencing reproductive parameters.

Pollinator selection by floral traits and color in a hybrid zone of Ipomopsis aggregata and I. tenuituba (Polemoniaceae) - P. Hernandez-Garcia (2004)
Albinos plants are usually discriminated by their pollinators. Exist the possibility that other pollinator drive a reproductive isolation on this plants. To observe if an albino of a plant commonly pollinated by hummingbirds can be selected by other pollinator we used the F1s of albinos of Ipomopsis aggregata and hybrids of them and I. tenuituba. We performed two experimental arrays to observed the selection of the hummingbirds and hawkmoths. The first array was a pale array where we selected albino and hybrid plants with pale flowers. The second array was the opposite, the plants selected were albino and hybrid plants with dark flowers. Also, both arrays had wild types of I. aggregata and I. tenuituba. In both arrays the hummingbird prefered the dark flowers but in the second array they visited the hybrids almost the same as the I. aggregata wild types. The hawkmoths were presented only for the first array where they did not show any preference by the color of the flowers. The hawkmoth can establish a population of albino I. aggregata or at less maintain their genes in the populations of I. aggregata.

DOES LINARIA VULGARIS, AN INVASIVE, INTERFERE WITH THE POLLINATION OF THE NATIVE SPECIES, POTENTILLA PULCHERRIMA? - B. A. Martin (2004)
The need for information on invasive species has been growing more and more pressing as they continue to spread and crowd out native plants. Alarm over invasive species is often concerned with the vegetative crowding and homogenized habitats that they create. It has recently been recognized that the competition for pollinators between invasive and native plants is a pressing issue. This paper explores the competition over pollinator visitation between Linaria vulgaris, an invasive, and Potentilla pulcherrima, a native. Pollinator visits to patches with 100% P. pulcherrima were observed and compared with visitation to patches with 50% P. pulcherrima and 50% L. Linaria. Results yielded no significant difference between the number of visitors to P. pulcherrima when L. vulgaris was present. The presence of L. vulgaris did, however, alter the set of P. pulcherrima visitors. The alteration of the pollinator set of P. pulcherrima may or may not be important and future research should be conducted to determine the importance of different pollinators.

Predator-induced resource heterogeneity in a stream food web - A. R. McIntosh; B. W. Taylor; B. L. Peckarsky (Ecology, 2004)
Heterogeneous distributions of resources and organisms are characteristic of most ecosystems, but empirical understanding of the causes and consequences of heterogeneity is limited. We investigated whether predatory fish influenced the heterogeneity (spatial variability) of resources (algae) by modifying the behavior of primary consumers (mayflies). We hypothesized that fish would indirectly increase resource heterogeneity by reducing grazer activity, and that higher densities of grazers would reduce resource heterogeneity only in the absence of fish. We measured the effects of predator cues (brook trout odor) on grazer behavior (Baetis) and algal heterogeneity in mesocosms (∼1 m2) and in simple natural systems (30-m reaches of adjacent fishless streams). In addition, we measured grazer and algal distributions in complex natural streams that varied in grazer density, presence of fish, and physical conditions. Fish odor altered mayfly grazing behavior (measured using a simple behavioral bioassay) and increased algal heterogeneity (measured by Morisita's index at the scale of individual rocks) in mesocosms and manipulated streams. Furthermore, natural streams with higher grazer densities had lower algal heterogeneity, but only if they were fishless. Interestingly, the presence of brook trout decoupled the link between grazer density and algal heterogeneity in natural streams. These observations indicate that release from the threat of predation or increased densities of grazers can homogenize algal resources in fishless streams. We hypothesize that altered foraging in environments with predatory fish, independent of grazer density, led to increased resource patchiness, possibly by allowing the influence of variation in physical characteristics (e.g., flow and substratum) to predominate or by changing grazer microhabitat use. These results support theoretical predictions that factors affecting primary consumer behavior also alter resource heterogeneity.

Specialization, pollination syndromes, and the evolution of floral diversity - M. R. Dudash; C. B. Fenster; W. S. Armbruster; P. T. Wilson; James D. Thomson (Annual Reviews of Ecology and Systematics, 2004)

Comparison of Arthropod Diversity between Perennial Shrub versus Evergreen Tree Habitats at Sites Near Gothic, CO - D. Esparza (2004)
There are numerous species of organisms that live in woody vegetation. Their species diversity will be equal to the total number of species and their relative abundance. This study compared the species diversity of arthropods between perennial shrubs and evergreen trees. I hypothesized that a larger surface area found in the perennial shrubs would provide more niches for the arthropods to utilize, giving them greater species richness. Five different sites for each vegetation class located near Gothic, Colorado were selected. Large willows were selected and measured in order to equalize the area of conifer being sampled. Two trees were sampled per vegetation class, by using a beat-sheet to collect arthropods and beating the vegetation for a total of two minutes. All specimens collected were sorted and identified to morpho-species. The Shannon Diversity Index analysis demonstrated that there was a significant difference in species diversity between the two vegetation classes. The number of species in the conifers was greater than willows. Statistical analysis by an ANOVA test, also demonstrated that there is significant difference between the number of species between conifers and willows, conifers having lager numbers of species and greater abundance abundance.

Yellow-bellied marmots (Marmota flaviventris) hibernate socially - S. Im; A. Nicodemus; C. Zugmeyer; Daniel T. Blumstein (Journal of Mammalogy, 2004)

The ecology of pollination and nectar robbing in Linaria vulgaris in the Colorado Rocky Mountains (TSpace, 2004)
Cheaters affect most mutualisms, but their effects remain misunderstood. This thesis

The Effects of Distance From a Yellow-Bellied Marmot Burrow on Plant Diversity - L. Lochhead (2004)
Mammal mounds have been found to have diverse effects on vegetation. The area around yellow-bellied marmot (Marmota flaviventris) burrows was examined for different morphospecies and plant cover to find if diversity decreased near a burrow. Morphospecies were identified to family to look for trends in species composition. The number of morphospecies was found to decrease nearer to a burrow and plant cover was significantly lower immediately next to a burrow. Of the 13 plant families found, the number of morphospecies within Poaceae and Fabaceae experienced a moderately significant decrease near the burrow, and Asteracae experienced a significant decrease. This may be due to herbivory or because marmots like to excavate burrows where plants with more structural support grow to help maintain the solidarity of the burrow.

Ryan, C.K., 2002, Harry Gunnison Brown – An Orthodox Economist and His Contributions - Domenico da Empoli (Journal of Public Finance and Public Choice, 2004)
Abstract Ryan, C.K., 2002, Harry Gunnison Brown - An Orthodox Economist and His Contributions , Oxford, Blackwell, pp. 270, US$ 35.00, ISBN 1-4051-1156-9.

Locomotor ability and wariness in yellow-bellied marmots - F. Ransler; M. Seymour; A. M. Runyan; S. Im; A. Nicodemus; T. Stark; C. Zugmeyer; J. C. Daniel; Daniel T. Blumstein (Ethology, 2004)
Animals employ a variety of behaviors to reduce or manage predation risk. Often, these are studied in isolation, but selection may act on packages of behavior that are referred to as behavioral syndromes. We focused on yellow- bellied marmots (Marmota ﬂaviventris) and examined three commonly studied antipredator behaviors. We ﬁtted general linear models to explain variation in maximum running speed, time allocated to vigilance and foraging during bouts of foraging, and ﬂight initiation distance (FID). Marmot maximum running speed was inﬂuenced by the substrate run across; marmots ran fastest across dirt or low vegetation and slowest across stones or talus. Incline and several other variables shown to aﬀect running speed in other marmot species failed to explain signiﬁcant variation in yellow-bellied marmots. From these results we expected marmots to be sensitive to substrate while foraging, but insensitive to incline. However, time allocated to foraging was aﬀected by incline but not by substrate. In bouts of foraging observed in diﬀerent habitats, and on diﬀerent inclines, more time was allocated to foraging and less to vigilance on steep slopes and less on level ground. Substrate inﬂuenced FID. Marmots in tall vegetation were less tolerant of an approaching person than were those in shorter vegetation. Finally, we found signiﬁcant correlations between the residuals from the maximum running speed model and the residuals from the time allocated to vigilance and foraging models. We found a tendency for marmots that ran slower than predicted to be less vigilant while foraging. We also found that relatively slow marmots engaged in more active foraging and less vigilance during foraging bouts. This ﬁnding suggests a Ôlocomotor ability- wariness while foragingÕ syndrome. It also suggests that vulnerable individuals minimize their exposure while foraging. U. S. Copyright Clearance Center Code Statement: 0179-1613/2004/1108–615/$15.00/0 www.blackwell-synergy.com 616 D. T. Blumstein et al. Corresponding author: Daniel T. Blumstein, Department of Ecology and Evolutionary Biology, 621 Young Drive South, University of California, Los Angeles, CA 90095-1606, USA. E-mail: marmots@ucla.edu

Do dandelion flowers influence seed set of a native plant (Delphinium nuttallianum) in subalpine meadows? - Kenneth L. Jones (American Midland Naturalist, 2004)

Assessing the substitutability of mitigation wetlands for natural sites: estimating the restoration lag costs of wetland mitigation - F. J. Hitzhusen; J. J. Gutrich (Ecological Economics, 2004)

Cardamine cordifolia Pollination effects on seed and fruit production - M. Rodriguez (2004)
I investigated the pollination ecology of Cardamine. Cordifolia, and how pollinators affected fruit and seed production especially in relation to variation in herbivory and habitat type in 2 different sites. Site 1 was more exposed to the sunlight and site 2 was less exposed to the sunlight. I investigated the degree of self –compatibility, pollinator-visitation rates, correlation between floral traits and plant height, and fruit and seed production. I hypothesized that outcrossed pollen supplemental to flowers would increased fruit and seed set, that herbivore damage would impact the strength of pollen limitation and that longer floral traits and taller plants would be associated with increased pollinator visitation and plant reproduction. C. cordifolia was both self-compatible and pollinator limited, but outcrossed pollen supplemental plants produced more fruits and seeds than self-pollinated flowers. The difference in the proportion of fruit and seed set between no bag outcrossed and the open pollination treatments suggested pollen limitation of seed set. Pieridae (cabagge milky butterflies) performed more visits than any other visitors. Herbivore damage resulted in changes in how pollinators selected a plant. I found no correlation between floral traits and plant height. This study showed the complexity of a plant-animal interaction, and the benefits that each organism receive from it.

Estimating species richness at large spatial scales using data from discrete plots - R. Krishnamani; H. Harte; A. Kumar (Ecography, 2004)
Estimating species richness in large biomes is a central challenge in ecology and conservation biology. However, accurate census data is often available only from small discrete plots distributed within the biome. Using tree species richness data collected from 48 plots (0.25 ha each) widely distributed through 60 000 km 2 in the rainforests of the Western Ghats of southern India, we test the application of a proposed method for estimating species richness at large scales from measured species commonalities between pairs of censused plots. We show that the method allows extrapolation of species richness from a scale of 0.25 ha plots to that of the entire biome, or 10 5 km 2 .

Effect of Rock Size, Age, and Distance on the Biodiversity of Lower Copper Creek Area Lichens: A Test of the Theory of Island Biogeography - C. L. Elder (2004)
This study analyzed the species richness and abundance of lichens along Copper Creek, Gothic, CO., in relation to boulder size and distance from a source, in an attempt to illustrate the theory of island biogeography. Mine tailings were also sampled to determine the colonization and growth rates of lichens in the 120 years since they were created. Boulders of various ages, sizes and distances were measured for species richness and relative percent surface coverage. A slight relationship was found between size and number of lichen species present, but none between boulder distance and species. No significant difference was found at mine sites,either between tailings and bedrock, or between sites and the undisturbed scree slopes or boulder fields I analyzed for the body of my study. The general lack of statistical differences may simply be due to these hardy organisms’ excellent ability to disperse, colonize and persist in their boulder ‘island’ habitats.

Zeolites and Associated Minerals from the Table Mountains near Golden, Jefferson County, Colorado - Daniel E. Kile (Rocks & Minerals, 2004)

Are mayfly anti-predator responses to fish odour proportional to risk? - A. R. McIntosh; B. L. Peckarsky (Archiv fur Hydrobiologie, 2004)

Comparing predator-induced changes in stream insects with varying vulnerabilities to risk of predation - L. Marko (2004)
Mayflies in high-elevation streams in Colorado are more vulnerable to risk of predation based on their relative drift propensisties. Baetis bicaudatis, a mayfly that has high drift propensity, has been shown to respond to predation risk by accelerating its metamorphosis into an adult, which results in smaller body size and a reduced fecundity. Other species of mayflies with lower drift propensities (either as a result of a fixed behavior, or a response to predation risk) , as well as other aquatic insects, such as, caddisflies that do not drift may have a different response to predators. We conducted field surveys of five fish and five fishless streams to determine the effect of predation risk on aquatic insect response (i.e., body size and fecundity). Three species of mayfly were collected: Rhithrogena robusta, Epeorus deceptivus, and Cinygmula spp. and one species of caddisfly was collected: A. grandis. We also conducted a stream micrcosm experiment to determine if the patterns seen in nature for E. deceptivus and A. grandis could be induced with just fish chemical cues. A general trend was seen in field surveys that showed an increase in R. robusta ( power = 0.8264) body size in fish streams. A. grandis did not show a body size response to stream treatment in field surveys, but there was a higher number of eggs produced in fish streams (power = 0.0542). These results indicate that insects with high vulnerabilities but low risk to predation may not be affected by predator-induced changes in body size.

Functions of staminate flowers in andromonoecious Pseudocymopterus montanus (Apiaceae, Apioideae) - T. Watkins; L. M. Graceffa; D. Cordray; M. A. Schlessman; N. C. Underwood (Plant species biology, 2004)
Abstract The pollen donor and pollinator attractor hypotheses are non‐exclusive alternative explanations for the functions of the staminate flowers of andromonoecious plants. We tested assumptions and predictions of both hypotheses using the andromonoecious perennial Pseudocymopterus montanus (Apiaceae, Apioideae), in which staminate flowers are approximately one‐third as massive as perfect ones and sequentially blooming umbels bear varying proportions of staminate flowers. We confirmed that larger umbels receive more visits than smaller ones. We demonstrated that fluorescent dye is a suitable analog of P. montanus pollen and that larger umbels donate more dye to nearby recipient umbels than do smaller ones. We showed that experimental removal of staminate flowers lowers fruit set only in primary umbels. We used stepwise multiple regressions to examine the effects of staminate flowers on xenogamous pollination, overall (xenogamous and geitonogamous) pollination and fruit set. The regressions revealed significant effects of staminate flowers only for cross pollination of primary umbels. We concluded that in P. montanus , staminate flowers function primarily as pollen donors.

Lifetime reproductive success of territorial yellow-bellied marmots - Kenneth B. Armitage (Oecologia Montana, 2004)

Impact of the Western Thatching Ant (Formica obscuripes) on - K. Jenks; J. S. Reithel (URBEE, 2004)

The effect of body condition of yellow-bellied marmots on time allocation to vigilance and food acquisition while foraging - L. Lochhead (2004)
Condition can influence many traits. I looked at how condition affects time allocation while foraging for yellow-bellied marmots (Marmota flaviventris) by taking two minute focal samples of adults and yearlings and recording their behavior. Each focal was paired with measurements of condition collected from the nearest trapping date. Overall, condition did not affect time allocation for foraging. When the individuals were separated into age-sex cohorts, condition was not significantly correlated with time allocation for females. The sample size of adult males was too small to form any conclusions, but as condition improved time allocation to both foraging and looking increased. Yearling males had a moderately significant tendency to trade-off looking for foraging if they were in poorer condition. Yearling males may be the only group to respond because they are the only cohort that must disperse and condition may be essential for the survival of dispersing individuals.

MAZZETTIITE, Ag3HgPbSbTe5, A NEW MINERAL SPECIES FROM FINDLEY GULCH, SAGUACHE COUNTY, COLORADO, USA - L. Bindi; C. Cipriani (The Canadian Mineralogist, 2004)
Mazzettiite, ideally Ag3HgPbSbTe5, is a new mineral species from Findley Gulch, Saguache County, Colorado. It occurs as anhedral to subhedral grains up to 200 m across, closely associated with altaite together with galena in a gangue of quartz. Mazzettiite is opaque with a metallic luster and a black streak. It is brittle; the Vickers hardness (VHN25) is 101 kg/mm2 (range: 96–106) (Mohs hardness of ~3–3). The density could not be measured because of the small grain-size [density (calc.) = 9.04 g/ cm3]. In reflected light, mazzettiite is light grey, weakly to moderately bireflectant, and weakly pleochroic from slightly greenish grey to a slightly darker bluish grey. Under crossed polars, it is moderately anisotropic, without characteristic rotation-tints. Internal reflections are absent. Reflectance percentages in the range 400–700 nm are tabulated, with values for the four COM wavelengths interpolated. The values for Rmin and Rmax are 45.6, 46.1 % (470 nm), 46.1, 46.6 % (546 nm), 46.3, 47.0 % (589 nm), and 46.4, 47.1 % (650 nm), respectively. The unit-cell parameters of mazzettiite were derived by comparison with petrovicite, Cu3HgPbBiSe5, to which it shows strong similarities, both from a chemical and a structural point of view. Mazzettiite is orthorhombic, space group Pna21 or Pnam, with a 16.495(6), b 14.762(7), c 4.506(2) Å, V = 1097.2(8) Å3, Z = 4. The strongest seven powder-diffraction lines [d in Å (I/I0)(hkl)] are: 3.65(60)(330), 3.26(50)(131), 3.17(60)(430), 3.01(100)(520), 2.754(60)(440), 2.137(50)(122), and 1.806(55)(561). A mean of 20 electron-microprobe analyses gave Ag 21.6(3), Hg 13.6(2), Pb 14.1(3), Sb 8.1(1), Te 42.7(3), total 100.1 wt.%, corresponding, on the basis of a total of 11 atoms, to Ag2.99Hg1.01Pb1.02

Adaptive speciation - Nickolas M. Waser; Diane R. Campbell (2004)

Response of plant pathogens and herbivores to a warming experiment - S. Gusewell; B. A. Roy; John Harte (Ecology, 2004)
Pathogens and herbivores can severely reduce host fitness, potentially leading to altered succession rates and changes in plant community composition. Thus, to predict vegetation dynamics under climate change, it is necessary to understand how plant pathogens and herbivores will respond. Pathogens and herbivores are predicted to increase under climate warming because the amount of time available for growth and reproduction will increase. To test this prediction, we used a warming experiment in which heaters were suspended over a natural montane meadow for 12 years. In the summer of 2002, we quantified damage by all the observable (aboveground) pathogens and herbivores on six of the most common plant species (Artemisia tridentata, Helianthella quinquenervis, Erigeron speciosus, Potentilla gracilis, Potentilla hippiana, and Lathyrus leucanthus). We found that plants in the earlier melting plots generally had the most damage and were attacked by a larger number of species, which is consistent with predictions. However, although the overall trend was an increase in damage with warmer temperatures and earlier snowmelt, some pathogens and herbivores performed better in cooler or later melting plots. The idiosyncratic response of each species to environmental conditions suggests that there are likely to be changes in community composition as the planet warms.

Natural selection in Ipomopsis hybrid zones: implications for ecological speciation - Diane R. Campbell (New Phytologist, 2004)

Do individual differences influence flight initiation distance? - A. M. Runyan; Daniel T. Blumstein (Journal of Wildlife Management, 2004)
Flight initiation distance (FID), or the distance between a prey animal and an approaching intruder when the prey initiates its escape, is an important factor in wildlife management. We conducted a study on individually identified yellow-bellied marmots (Marmota flaviventris) to test 3 key assumptions of FID research: (1) differences in individual responses are small enough so as not to confound results; (2) pseudoreplication may bias results; and (3) habituation and sensitization can be studied without knowledge of individuals. We found that individual identity was not a significant predictor of FID. Furthermore, a moderate degree of pseudoreplication did not significantly affect the results of most analyses. However, individuals differed greatly in their rates of habituation, such that habituation was apparent only when individual identity was known and could not be detected without knowledge of individuals. If our marmot results can be generalized to other species, they suggest that researchers need not be concerned about individual identity when studying variables largely dependent on environmental factors, but that identification of individuals is important for studies of properties of individuals, such as habituation.

The effect of climate change on the germination and growth rates of young subalpine fir (Abies lasiocarpa) - E. Staaterman (2004)

Larval cannibalism, time constraints, and adult fitness in caddisflies that inhabit temporary wetlands - J. S. Alexander; J. Steinmetz; W. S. Brown; S. A. Wissinger (Oecologia, 2004)
The results of the laboratory experiment suggest that this species can metamorphose with a detritus-only diet, but development is extremely protracted, which is consistent with recent growth-development models that predict coupled rather than tradeoff responses to pre-threshold manipulation of larval diets.

Avian Risk Assessment: Effects of perching height and detectability - I. Rodriquez-Prieto; C. Zugmeyer; Esper S. Larsen; O. E. LeDee; E. Fernandez-Juricic; Daniel T. Blumstein (Ethology, 2004)
AbstractWe studied two components of predator risk assessment in birds. While many species are limited to seeking safety under cover or under ground, some birds can fly away from their predators and escape to trees. If birds in fact ‘feel’ safer (e.g. perceive less risk) in trees, we would expect them to tolerate closer approach by a potential terrestrial predator. Another component of safety is at which point the animal detects an approaching threat, which we expected to increase with eye size, assuming eye size is a surrogate for visual acuity. We used the distance birds moved away from an approaching human [flight initiation distance (FID)] as a metric to determine whether birds associated a lower risk of predation by being in trees, and we used the distance at which birds first displayed alert behaviors from an approaching human (alert distance) to determine if birds with larger eyes had higher detection distances. Although some species were affected by tree height, we found no clear pattern that birds assessed themselves to be at a lower risk of predation when they were ≥3 m above the ground compared with being <3 m above ground. In the 10 species for which height had any significant effect on FID, birds ≥3 m off the ground had greater FIDs in six species, but the remaining three species had the opposite response. While we found a significant positive relationship between eye size and alert distance in 23 species, the relationship was not present in a phylogenetic analysis using independent contrasts, which suggests that the apparent relationship was influenced strongly by the association between the studied species. Together, these results suggest that birds do not obviously associate being in a tree with safety, and that variations in visual acuity, per se, cannot be used as a general indicator of differences in alert distances, as previously suggested in the literature.

'Anti-bee' and 'pro-bird' changes during the evolution of hummingbird pollination in Penstemon flowers - M. C. Castellanos; P. T. Wilson; James D. Thomson (Journal of Evolutionary Biology, 2004)
Abstract Floral phenotypes may be as much the result of selection for avoidance of some animal visitors as selection for improving the interaction with better pollinators. When specializing on hummingbird-pollination, Penstemon flowers may have evolved to improve the morphological fit between bird and flower, or to exclude less-efficient bees, or both. We hypothesized how such selection might work on four floral characters that affect the mechanics of pollen transfer: anther/stigma exsertion, presence of a lower corolla lip, width of the corolla tube, and angle of flower inclination. We surgically modified bee-pollinated P. strictus flowers changing one trait at a time to make them resemble hummingbird-pollinated P. barbatus flowers, and measured pollen transfer by bumblebees and hummingbirds. Results suggest that, apart from ‘pro-bird’ adaptations, specific ‘anti-bee’ adaptations have been important in shaping hummingbird-flowers. Moreover, some trait changes may have been selected for only if changing in concert with other traits.

Salt Evolution as a Control on Structural and Stratigraphic Systems: Northern Paradox Foreland Basin, Southeast Utah, USA - Bruce D. Trudgill; Nick Banbury; John R. Underhill (SOCIETY OF ECONOMIC PALEONTOLOGISTS AND MINERALOGISTS eBooks, 2004)
The Paradox Basin is an asymmetric foreland basin, developed along the southwestern flank of the Uncompahgre uplift in southeast Utah and southwest Colorado, USA. This large basin (265km by 190km) developed during the middle Pennsylvanian-Permian ancestral Rocky Mountain orogenic event. Salt structures in the northern Paradox Basin form a variety of structural styles ranging from deeply buried salt pillows to complexly faulted diapirs and salt walls exposed at the surface. Complex intra-formational unconformities and rapid lateral stratigraphic facies variations indicate that salt structures were active over at least 75 Ma.

Influence of the Blue Mesa Reservoir on the Red Creek Landslide, Colorado - Shauna Walker (Environmental and Engineering Geoscience, 2004)
Research Article| January 01, 2004 Influence of the Blue Mesa Reservoir on the Red Creek Landslide, Colorado SCOTT R. WALKER; SCOTT R. WALKER 1URS Corporation, 8181 East Tufts Avenue, Denver, CO 80237 Search for other works by this author on: GSW Google Scholar PAUL M. SANTI PAUL M. SANTI 2Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401 Search for other works by this author on: GSW Google Scholar Author and Article Information SCOTT R. WALKER 1URS Corporation, 8181 East Tufts Avenue, Denver, CO 80237 PAUL M. SANTI 2Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401 Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 Copyright © 2004 Geological Society of America Environmental & Engineering Geoscience (2004) 10 (1): 13–26. https://doi.org/10.2113/10.1.13 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation SCOTT R. WALKER, PAUL M. SANTI; Influence of the Blue Mesa Reservoir on the Red Creek Landslide, Colorado. Environmental & Engineering Geoscience 2004;; 10 (1): 13–26. doi: https://doi.org/10.2113/10.1.13 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 SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract Intermittent movement of the Red Creek Landslide has caused settling and cracking of U.S. Highway 50 west of Gunnison, Colorado, for more than 30 years. Significant degradation of the roadway has resulted in extensive repair costs and traffic delays. Geomorphic and computer stability analyses support the theory that the active Red Creek Landslide is the partial reactivation of a larger, ancient paleolandslide, with a basal rupture surface located predominantly in the Morrison Formation. The original paleolandslide may have been triggered by an earthquake coupled with a high water table. Creation of the Blue Mesa Reservoir submerged approximately 50 percent of the paleolandslide. Some clay layers within the Morrison Formation are susceptible to severe weakening by slaking, and the resulting reduction in strength, combined with a pre-existing failure plane at depth, contributed to the recent partial reactivation of the paleolandslide. Seasonal rapid drawdown of the Blue Mesa Reservoir acts as the trigger for movement, and large drawdowns have been correlated with periods of slope movement. The effects of rapid drawdown could be minimized if reservoir drawdown can be limited to rates less than the critical calculated values. Historic excavation near the toe may explain why other paleolandslides around the reservoir have not reactivated under identical drawdown conditions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Writing a RUI proposal: strategies for success - Howard Whiteman (Council on Undergraduate Research Quarterly, 2004)

Species coexistence in a food web with intraguild predation - E. Tan; T. Romanuk (URBEE, 2004)

The dual role of floral traits: pollinator attraction and plant defense - L. S. Adler; Alison K. Brody; Rebecca E. Irwin (Ecology, 2004)
Plants are under siege from a diversity of enemies that consume both leaf and floral parts. Plants resist damage to leaves in a variety of ways, and we now have a rich literature documenting how plants defend themselves against herbivore attack. In contrast, the mechanisms by which plants resist enemies that consume floral parts or resources are much less known, even though damage to floral tissue usually has tighter links to plant fitness than damage to leaf tissue. Many plants experience nectar robbing, whereby floral visitors remove nectar from flowers, often without pollinating. Nectar robbers can reduce plant fitness to degrees comparable to, or even surpassing, reduction by herbivores. However, because nectar attracts both pollinators and nectar robbers, plants face a dilemma in defending against nectar robbers without also deterring pollinators. Here, we extend the conceptual framework of resistance to herbivores to include resistance to nectar robbers, focusing on nectar traits. We review published data and find that an array of nectar traits may deter robbers without deterring pollinators. Although resistance traits against robbers have been broadly identified, the costs and benefits of these traits in terms of plant fitness remain poorly understood. We present data showing that a nectar trait (dilute nectar) might directly, as well as indirectly, benefit plant fitness by deterring nectar-robbing bumble bees of Ipomopsis aggregata without deterring hummingbird pollinators. However, the magnitude of any plant fitness benefit will depend on the degree to which plants are pollen- vs. resource-limited in a given year. The results of our work offer both conceptual and empirical insight into how plants cope with attack by nonpollinating floral visitors through a relatively unexplored trait, nectar.

Ecosystems impacts of climate change: snowmelt timing, species diversity, and plant productivity - J. Reistetter (2004)
A 14 year warming experiment being conducted in a subalpine meadow has resulted in several physical changes, including advanced date of snowmelt, a decrease in soil moisture, and increased soil temperature in heated plots versus control plots. These microclimate changes have led to a shift in plant community composition towards dominance of sagebrush (Artemisa tridentata) at the expensive of herbaceous forb plant species. Among the forb species, deep rooted species have not been as adversely affected as shallow rooted species. Within the experimental warming plots, there is also a positive, although non-significant, correlation between snowmelt timing and species richness with earlier melting plots having lower species richness. Using observational data along a naturally-occurring snowmelt gradient, this study attempted to identify if the relationships between snowmelt timing and species richness and community composition hold true across a larger meadow area, and if snowmelt timing correlates to other important ecosystem process such as plant productivity and soil carbon storage. We also looked for evidence in support of a hypothesized link between plant diversity and ecosystem function. Snowmelt timing did not correlate with species richness, aboveground biomass, or soil organic carbon, although it was correlated with community composition, with earlier snowmelt leading to a greater proportion of shallow rooted forbs and a greater presence of sagebrush. Species richness did not correlate with aboveground biomass or soil organic carbon, however plant community composition did show some significant correlation with 1 ecosystem functioning. Sagebrush was present only in early melting plots, and plots with sagebrush had significantly higher soil organic carbon than plots without sagebrush. Forb composition was significantly correlated with aboveground biomass, with plots containing more deep rooted forbs having higher aboveground biomass.

Structural implications of underground coal mining in the Mesaverde Group in the Somerset Coal Field, Delta and Gunnison Counties, Colorado - Greg Hunt; Eric Robeck; Wendell Koontz; Christopher J. Carroll (Geological Society of America eBooks, 2004)
The theme of the 2004 GSA Annual Meeting and Exposition, "Geoscience in a Changing World," covers both new and traditional areas of the earth sciences. The Front Range of the Rocky Mountains and the High Plains preserve an outstanding record of geological processes from Precambrian through Quaternary times, and thus serve as excellent educational exhibits for the meeting. With energy and mineral resources, geological hazards, water issues, geoarchaeological sites, and famous dinosaur fossil sites, the Front Range and adjacent High Plains region provide ample opportunities for field trips focusing on our changing world. The chapters in this field guide all contain technical content as well as a field trip log describing field trip routes and stops. Of the 25 field trips offered at the Meeting, 14 are described in this guidebook, covering a wide variety of geoscience disciplines, with chapters on tectonics (Precambrian and Laramide), stratigraphy and paleoenvironments (e.g., early Paleozoic environments, Jurassic eolian environments, the K-T boundary, the famous Oligocene Florissant fossil beds), economic deposits (coal and molybdenum), geological hazards, and geoarchaeology.

The Effect of an Ant-Aphid Mutualism on Deer Herbivory of Valariana edulis - J. Turk; J. S. Reithel (2003)

Spatial distribution and nest site selection in a Colorado cavity-nesting bird community - N. Losin (2003)

Flowering phenology and compensation for herbivory in Ipomopsis aggregata - C. D. Neefus; R. S. Freeman; Alison K. Brody (Oecologia, 2003)

Subalpine meadow flowering phenology responses to climate change: integrating experimental and gradient methods - J. A. Dunne; K. J. Taylor; John Harte (Ecological Monographs, 2003)
We integrated experimental and natural gradient field methods to investigate effects of climate change and variability on flowering phenology of 11 subalpine meadow shrub, forb, and graminoid species in Gunnison County, Colorado (USA). At a subalpine meadow site, overhead electric radiant heaters advanced snowmelt date by 16 d and warmed and dried soil during the growing season. At three additional sites, a snow removal manipulation advanced snowmelt date by 7 d without altering growing season soil microclimate. We compared phenological responses to experimental climate change with responses to natural microclimate variability across spatial gradients at small and landscape scales, as well as across a temporal gradient from a separate study. Both manipulations significantly advanced timing of flowering for the group of species and for most species individually, closely paralleling responses of timing to natural spatial and temporal variability in snowmelt date. Snowmelt date singularly explained observed shifts in timing only in the earliest flowering species, Claytonia lanceolata. Among all other species except Artemisia tridentata var. vaseyana, the latest flowering species, a consistent combination of temperature-related microclimate factors (earlier snowmelt date, warmer soil temperatures, and decreased soil degree-days) substantially explained earlier timing. Both manipulations also extended flowering duration for the group of species, similar to species' responses to natural snowmelt variability at small spatial scales. However, only early flowering species displayed consistent, significant changes in duration, with extended duration related to earlier snowmelt or warmer spring soil temperatures. Soil moisture was generally not a significant explanatory factor for either timing or duration of flowering. Best-fit microclimate models explained an average of 82% of variation in timing but only 38% of variation in duration across species. Our research demonstrates the value of comparing and synthesizing results of multiple field methods within a single study. This integrated approach makes it easier to identify robust community-wide trends, as well as species-specific responses of phenology to climate change. The predicted short-term flowering phenology responses to temperature-related aspects of climate change may lead to longer term asynchronies in interspecific interactions, potentially altering population and evolutionary dynamics, community structure, and ecosystem functioning. Corresponding Editor: S. C. Pennings

Individual differences and reproductive success in yellow-bellied marmots - D. H. Van Vuren; Kenneth B. Armitage (Ethology Ecology and Evolution, 2003)
Mirror-image stimulation (MIS) was used to determine the individual behavioral phenotypes of 90 adult, 132 yearling, and 135 young yellow-bellied marmots (Marmota flaviventris). Linear typal analysis (LTA) was used to group individuals based on similarities in their MIS scores. Principal component analysis (PCA) was used to evaluate the patterns of variation in behaviors and discriminant function analysis (DFA) was used to determine if there were consistent differences in marmot behavior. LTA produced two interpretable groups that were significantly and negatively correlated. Marmots in each group formed a shy-bold continuum. Bold animals were those that approached the mirror early and made nose contact with the image whereas shy animals approached the mirror late in the run, spent time in the back half of the arena, and frequently chirped at the image. Behaviors shifted with age; young were predominantly bold and adults were predominantly shy. This shift appears to be developmental and not genetically determined. Reliability and predictability analyses indicated that there is a 75% probability that a MIS run correctly identifies an individual's behavioral phenotype. The probability increases to 90% for those individuals with high loading scores. Play, agonistic, and amicable behaviors of female yearlings recorded in the field were significantly correlated with their MIS behavioral phenotypes whereas only play of male yearlings was so correlated. Correlations among eight life-history traits of adult females were independent of behavioral phenotypes. Shy females were more likely to be associated with female non-kin, produced more daughters, and were more likely to be immigrants. Among female yearlings, shy phenotypes were likely to become recruits and bold phenotypes were more likely to disperse. Bold adult females recruited yearlings regardless of their behavioral phenotype whereas shy adult females recruited primarily shy yearlings and the majority of bold yearlings dispersed. Among adult males, shy phenotypes were more likely to be territorial-colonial and to produce more young. Lifetime reproductive success (LRS) of females was strongly related to the number of years of residency, which was strongly correlated with the frequency of reproduction and the production and recruitment of offspring. The demographic patterns were independent of behavioral phenotype. Behavioral phenotype impacts demographic trends mainly by increasing the recruitment of daughters by bold females. LRS of males depends on the length of residency. Shy males have a higher LRS because they are territorial-colonial for a longer time and produce more young. Bold individuals appear to be those that are sub- ordinate and attempt to affiliate with other marmots whereas shy individuals appear to be dominant and less likely to be affiliative. By being more aggressive, the shy marmot is more likely to achieve residency as a yearling or adult whereas the more affiliative adult is more likely to recruit offspring, but affiliative yearlings are less likely to become recruits, especially when the adults are the dominant, “shy” individuals.

Group hiberation does not reduce energetic costs of young yellow-bellied marmots - B. C. Woods; Kenneth B. Armitage (Physiological and Biochemical Zoology, 2003)

Wild mammals of north america: biology, management, and conservation - Kenneth B. Armitage (2003)

Adaptive strategies and diversity in marmots (2003)

Lower Pennsylvanian stratigraphy of the Central Colorado Trough - Bryan Edward Musgrave (ThinkTech (Texas Tech University), 2003)
The Central Colorado Trough formed as a result of the uplift of the Ancestral Rocky Mountains. With uplift, sediments were eroded from the adjacent highlands and deposited in the trough. The Lower Pennsylvanian stratigraphy of the Central Colorado Trough was determined based on outcrops in the southern Mosquito Range and Arkansas River Valley east of Salida, Colorado.\n\nThe Kerber Formation is the oldest Pennsylvanian strata in the Central Colorado Trough and was derived from the erosion of older Paleozoic sedimentary rocks and some crystalline basement rocks. It was deposited in alluvial fan and braided streams environments near the edges of the trough. Along the axial portion of the Trough, it was deposited in braid-delta and shallow marine environments. As marine incursion occurred from the northwest, a retrogradational sequence developed. Based on conodont faunas, the upper Kerber Formation is late Morrowan to Atokan in age. Because the strata of the Central Colorado Trough are intimately related to the initial uplift of the Ancestral Rocky Mountains, the formation of the Ancestral Rocky Mountains began no later than the late Morrowan.\n\nThe Kerber Formation correlates with the Belden Formation of the northern portion of the Trough based on the first appearance of the conodonts Idiognathoides sinuatus, Idiognathodus sinuosus, and Idiognathodus parvus. At Willard Springs they occur within the Belden, whereas they occur within the Kerber at Wells Gulch, 8 km to the south. The dark marine sediments of the Belden Formation extend further southward than previously documented, and approximately 127 m of section occurs at Willard Springs, northeast of Salida. At Willard Springs, the Belden Formation lies conformably above the Kerber Formation and conformably below the Sharpsdale Formation. This is the first time that the Belden has been documented m contact with the Sharpsdale Formation. At Wells Gulch and Box Canyon to the south, the Belden Formation grades into shallow-water carbonates and shales interbedded with Kerberand Sharpsdale-type elastics.\n\nThe Sharpsdale Formation was derived from the erosion of Precambrian crystalline basement rocks of the Uncompahgre Highland as the climate of the Pennsylvanian grew more arid. It was deposited in alluvial fan and braided stream environments near the edges of the trough. Along the axial portion of the trough, it was deposited in braid-delta and rare shallow marine environments. A northward prograding sequence developed as sediment influx exceeded local sea-level rise.

Effect of parasite load on song characteristics and response to aggression in male mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) - S. M. Gilman (2003)

Butterflies: Ecology and Evolution Taking Flight - P. R. Ehrlich; W. B. Watt; Carol L. Boggs; Carol L. Boggs (2003)

Ecological studies: population viability in plants: conservation, management, and modeling of rare plants - M. J. Leigh; G. Lowe; M. A. Morales; David W. Inouye (2003)

Effects of the presence of Linaria vulgaris on water potential in Potentilla diversifolia - A. England; B. J. Wilke (2003)

Genetic structure in a montane mayfly Baetis bicaudatus (Ephemeroptera: Baetidae), from the Rocky Mountains, Colorado - C. Cleary; P. B. Mather; John M. Hughes; M. Hillyer; B. L. Peckarsky (Freshwater Biology, 2003)
Summary1. Populations of a number of sub‐tropical stream insect species have been found to show unexpected patterns of genetic variation, with more differences between samples from the same stream than between whole streams or between subcatchments. Many samples also showed deviations from Hardy–Weinberg proportions. It has been proposed that these patterns result from limited numbers of matings contributing to a given stream reach, because adults emerge throughout the year, and low levels of larval drift between reaches. These patterns may be less likely in a northern hemisphere montane species with synchronous emergence of adults and high levels of drift. We tested the hypothesis that patterns of genetic variation in a montane mayfly from the Rocky Mountains, Colorado, would reflect a pattern of ‘isolation by distance’ with samples from the same creek being more similar than samples from different creeks and that deviations from Hardy–Weinberg proportions would be minimal.2. Based on allozyme variation, the hypothesis of minimal deviations from Hardy–Weinberg proportions was not supported and there was no evidence of isolation by distance. Nevertheless the levels of differentiation among samples from within the same stream were less than those reported for most subtropical species.3. Results from analysis of a fragment of the cytochrome oxidase gene (subunit 1) revealed contrasting patterns. The levels of genetic differentiation were an order of magnitude higher between streams than among samples within streams. In addition, although there was no significant isolation by distance effect overall, a nested clade analysis provided evidence for restricted gene flow with isolation by distance for some clades.4. We suggest that these contrasting results may reflect the differences in male and female dispersal patterns. While differentiation at nuclear gene markers (allozymes) give information about both male and female dispersal, mitochondrial DNA markers reflect only female dispersal. We suggest that in this species, female dispersal may be more restricted, perhaps mostly along stream channels, whereas male dispersal is more widespread. An alternative explanation for the different results is the different evolutionary rates of the mitochondrial and nuclear markers.

Costs and benefits of an ant-membracid mutualism in the absence of predation - M. Reylea (2003)

Rocky Mountain Biological Lab's 75th Anniversary Symposium, Crested Butte - Ian Billick (Bulletin of the Ecological Society of America, 2003)

Effects of food addition on life history of yellow-bellied marmots - B. C. Woods; Kenneth B. Armitage (Oecologia Montana, 2003)

Empirical evidence for nonselective recruitment and a source-sink dynamic in a mayfly metapopulation - C. C. Caudill (Ecology, 2003)
Dispersal among spatially subdivided populations and variability in local habitat patch quality can strongly affect local and regional population dynamics. A metapopulation of mayflies (Callibaetis ferrugineus hageni) was studied in which larvae developed in beaver ponds and emerged to the terrestrial habitat as adults; adult females had the potential to disperse among ponds before oviposition. Ponds (patches) differed in the presence or absence of trout. Densities of late instar larvae were more than an order of magnitude greater in fishless ponds. Estimates of adult production, migration, and oviposition rate were used to determine whether the difference in larval abundance between pond types was more consistent with a source–sink or balanced dispersal model. Patch quality among ponds (estimated by the emergence rate of adults) varied from 0 to ∼3900 individuals·m−2·yr−1, and was significantly lower in ponds with trout. Survivorship of adult females in the regional terrestrial habitat was low (1.7%). Consistent with the predictions of source–sink theory, local recruitment to the next generation was not related to local emergence. Moreover, comparison of emergence and recruitment revealed that some ponds were net exporters of females (sources) and others were net importers (sinks). Ovipositing females did not avoid ovipositing in ponds with trout. Overall, the data were consistent with a source–sink dynamic because patches differed in quality, and because there was net migration of individuals from sources to sinks. The results support the hypothesis that local and regional population dynamics are influenced by spatial variation in patch quality, and by the ability of individuals to both disperse among and assess the quality of habitat patches.

Ecologists seek to turn tide on Colorado River - Rebecca M. Dalton (Nature, 2003)

Linking pollinator visitation rate and pollen receipt - C. E. Engel; Rebecca E. Irwin (American Journal of Botany, 2003)
The majority of flowering plants require animals for pollination, a critical ecosystem service in natural and agricultural systems. However, quantifying useful estimates of pollinator visitation rates can be nearly impossible when pollinator visitation is infrequent. We examined the utility of an indirect measure of pollinator visitation, namely pollen receipt by flowers, using the hummingbird‐pollinated plant, Ipomopsis aggregata (Polemoniaceae). Our a priori hypothesis was that increased pollinator visitation should result in increased pollen receipt by stigmas. However, the relationship between pollinator visitation rate and pollen receipt may be misleading if pollen receipt is a function of both the number of pollinator visits and variation in pollinator efficiency at depositing pollen, especially in the context of variable floral morphology. Therefore, we measured floral and plant characters known to be important to pollinator visitation and/or pollen receipt in I. aggregata (corolla length and width and plant height) and used path analysis to dissect and compare the effect of pollinator visitation rate vs. pollinator efficiency on pollen receipt. Of the characters we measured, pollinator visitation rate (number of times plants were visited multiplied by the mean percentage of flowers probed per visit) had the strongest direct positive effect on pollen receipt, explaining 36% of the variation in pollen receipt. Plant height had a direct positive effect on pollinator visitation rate and an indirect positive effect on pollen receipt. Despite the supposition that floral characters would directly affect pollen receipt as a result of changes in pollinator efficiency, corolla length and width only weakly affected pollen receipt. These results suggest a direct positive link between pollinator visitation rate and pollen receipt across naturally varying floral morphology in I. aggregata. Understanding the relationship between pollinator visitation rate and pollen receipt may be of critical importance in systems where pollinator visitation is difficult to quantify.

Emergence cues of Baetis bicaudatus (Ephemeroptera: Baetidae) in a high altitude stream system - M. P. Harper (2003)

Forest carbon cycling along an elevation gradient: the influence of species and climate - L. M. Kueppers (2003)

Adaptation at specific loci. VII. Natural selection, dispersal and the diversity of molecular-functional variation patterns among butterfly species complexes (Colias: Lepidoptera, Pieridae) - E. H. Meyer; C. W. Wheat; W. B. Watt; Julien G. A. Martin (Molecular Ecology, 2003)
AbstractNatural genetic variants at the phosphoglucose isomerase, PGI, gene differ in spatial patterning of their polymorphism among species complexes ofColiasbutterflies in North America. In both lowland and alpine complexes, molecular–functional properties of the polymorphic genotypes can be used to predict genotype‐specific adult flight performances and resulting large genotypic differences in adult fitness components. In the lowland species complex, there is striking uniformity of PGI polymorph frequencies at a number of sites across the American West; this fits with earlier findings of strong, similar differences in fitness components over this range. In an alpine complex,Colias meadiishows similar uniformity of PGI frequencies within habitat types, either montane steppe or alpine tundra, over several hundred kilometres in the absence of dispersal. At the same time, large shifts (10–20%) in frequency of the most common alleles occur between steppe and tundra populations, whether these are isolated or, as in some cases, are in contact and exchange many dispersing adults each generation. Data on male mating success of commonC. meadiiPGI genotypes in steppe and tundra show heterozygote advantage in both habitat types, with shifts in relative homozygote disadvantage between habitats which are consistent with observed frequency differences. Nonadaptive explanations for this situation are rejected, and alternative, thermal‐ecology‐based adaptive hypotheses are proposed for later experimental test. These findings show that strong local selection may dominate dispersal as an evolutionary agent, whether or not dispersal is present, and that selection may often be the major force promoting ‘cohesion’ of species over long distances. This case offers new opportunities for integrating studies of molecular structure and function with ecological aspects of natural selection in the wild, both within and among species.

Reproductive competition in female yellow-bellied marmots - Kenneth B. Armitage (International Network on Marmots, 2003)

Rescue of stranded pollen grains by secondary transfer - K. A. Eisenhart; James D. Thomson (Plant Species Biology, 2003)
Secondary transfer of pollen can occur when a second pollinator remobilizes grains that had already been transferred to a flower by a previous pollinator. We used a pollen-color dimorphism to measure components of secondary transfer by bumble bees visiting the lily Erythronium grandiflorum. Remobilization was surprisingly high, ranging from 20% of grains deposited on stigmas to 90% of grains deposited on inner tepal surfaces. Because most of the grains that are remobilized would otherwise have been stranded on non- stigmatic surfaces, secondary transfer has the beneficial effect of returning lost grains to circulation.

Enhanced growth of sagebrush (Artemisia tridentata) in response to manipulated ecosystem warming - S. E. Alter; T. Perfors; John Harte (Global Climate Change, 2003)
AbstractGlobal models project impending climate changes that could significantly alter plant species composition in ecosystems. Climate manipulation experiments provide an opportunity to investigate such effects. Here we describe and apply a method for extracting the age‐detrended growth rate of sagebrush (Artemisia tridentata Nutt.) and show that experimental ecosystem warming enhances the growth rate of this shrub. Snowmelt date, not soil temperature or moisture, is demonstrated to be the dominant climate variable controlling the observed effect. Our findings suggest that global climate change will result in increased growth and range expansion of sagebrush near northern or high‐elevation range boundaries in the Western United States.

Effects of resource value on broad-tailed and rufous hummingbird behavior - A. F. Camfield (2003)

Defensive strategy to nectar robbing in Ipomopsis aggregata: floral nectar as a tolerance trait - R. M. Rizo (2003)
An earthflow that occurred in Gunnison County, Colorado created a natural laboratory to study plant succession. Plant succession and ants can effect the soil composition of grounds left bare and depleted of organic matter by the landslide. This study was conducted to examine if the described successional pathway and ant nests changed soil composition in the landslide. The study revealed that the described successional pathway increased soil organic content if it begins from bare ground and ends with possible climax community. Pioneer species did not initially contribute to a significant change on soil organic content. Ant nests, on the other hand, do increase soil organic content. Moisture results reveal that all sites differ in soil moisture and soil moisture retention. Observe interactions between ants and pioneer species has also raised question on the importance of insect and plant interaction during succession.

The response of Heracleum sphondylium (Apiaceae) and its herbivores to - M. Haamen; C. M. Clapp; K. Andrade; Kenneth L. Jones; J. S. Reithel (URBEE, 2003)

Is the hepatitis virus absent from yellow-bellied marmots? - Kenneth B. Armitage (Oecologia Montana, 2003)

Early-season herbivory and pollinator and antagonistic visitation rate: an examination of all possible visitors on female reproductive success of Ipomopsis aggregata - S. Baguskas (2003)

The responses of montane shrubs to spatial and temporal climate variation in - E. McCullough (URBEE, 2003)

Worker demography in the ant Formica neorufibarbis - Ian Billick (Ecological Entomology, 2003)
Abstract. 1. Patterns of worker demography in the ant Formica neorufibarbis were documented under natural conditions. 2. Some workers lived at least 4 years. 3. In 4 of 5 years, colonies were more likely to retain older workers than new workers. 4. Workers persisted for more years in colonies lacking queens than in queenright colonies.

The relative importance of spatial vs. temporal variability in generating a conditional mutalism - K. Tonkel; Ian Billick (Ecology, 2003)
We explored the relative importance of temporal vs. spatial variability to the conditionality of a mutualism between the treehopper Publilia modesta and the ant Formica obscuripes. The effect of the ants on the membracids varied considerably among years. When the effect of the ants on the membracids was estimated in five sites spread over 5 km there was mixed evidence for spatial conditionality in the mutualism. Using repeated surveys of nymph number we found that the effect of the ants on nymph number varied among sites through time. When total new adult production was examined, however, no such interaction between ants and location was evident. Aggregations displayed strong negative density-dependent adult production. Thus, while in some sites ants had a greater positive effect on nymph survivorship, aggregations at those sites produced proportionately fewer adults because of negative density dependence. Density dependence reduced or eliminated spatial differences in the effect of the ants on the membracids. Differences among sites did not explain spatial variation in the effect of ants on nymphs or new adult production. We conclude that temporal variability is much more important than spatial variability in generating conditionality in the mutualism. Corresponding Editor: P. Nonacs

Quality of food source affects female visitation and display rates of male Broad-tailed Hummingbirds - A. F. Camfield (Condor, 2003)
Abstract I studied the relationships among energy availability, female visitation rates, and male display rates in Broad-tailed Hummingbirds (Selasphorus platycercus). Feeders contained 10%, 20%, or 30% sucrose solutions; female visitation rates and male hummingbird display rates were measured. Display rates of male Broad-tailed Hummingbirds and visitation rates of females depended on the quality of the food source. The fact that male display rates matched female visitation rates provides further evidence that dive displays play a role in courtship. More work needs to be done to determine if the relationship between resource quality, female visitation, and male display rates shows a threshold contingent on food availability. La Calidad de los Recursos Alimenticios Afecta las Tasas de Visita de las Hembras y de Despliegues de Cortejo de los Machos en Selasphorus platycercus Resumen. Evalué las relaciones entre la cantidad de energía disponible, la tasa de despliegues de cortejo por parte de los machos y la tasa de visita por parte de las hembras en Selasphorus platycercus. Para los comederos utilicé soluciones de agua azucarada en concentraciones de 10%, 20% ó 30%, y medí las tasas de visita de las hembras y de despliegues de cortejo de los machos en cada período de observación (1 hora por período). Las tasas de cortejo de los machos y de visita de las hembras dependieron de la calidad de los recursos alimenticios. El hecho de que las tasas de despliegue de los machos se relacionaran directamente con las tasas de visita de las hembras indica la importancia de los despliegues de caída libre durante el cortejo en esta especie. Se necesitan más investigaciones para determinar si la relación entre la calidad de recursos alimenticios, las visitas de las hembras y las tasas de despliegue presenta un límite relacionado con la disponibilidad de alimento por encima del cual la forma de esta relación se modifica.

Does living in streams with fish involve a cost of induced morphological defense? - J. Dahl; B. L. Peckarsky (Canadian Journal of Zoology, 2003)
Previous studies have shown that chemical cues from brook trout (Salvelinus fontinalis) induce relatively longer caudal filaments and heavier exoskeletons in the mayfly Drunella coloradensis. These characters constitute morphological defences that reduce larval mortality from brook trout predation. There is also a potential fitness cost of living in streams with trout, as D. coloradensis females emerge at smaller sizes from streams with fish compared with females in streams without fish. In this study, we obtained additional data to evaluate the hypothesis that these costs of living in streams with fish could be attributed to inducible defences. A field survey of seven different streams showed that mature (black wing pad) female larvae from streams with fish invested a smaller proportion of their body mass in eggs than females maturing in streams without fish. Furthermore, a negative relationship between female allocation to eggs and to morphological defence characters (relative length of the caudal filament) provides evidence of a cost of inducible defences in this species.

Impact of nectar robbing on estimates of pollen flow: conceptual predictions and emperical outcomes - Rebecca E. Irwin (Ecology, 2003)
Pollen movement within and among plants affects levels of inbreeding and plant fitness as well as the spatial scale of genetic differentiation. Pollen movement has primarily been studied as a function of the direct relationships between plants and pollinators; however, nonpollinating floral visitors, such as some nectar robbers, may have indirect effects on pollen dispersal by altering plant–pollinator interactions. Theory predicts that nectar robbing should have indirect positive effects on plants by increasing pollen dispersal distance and reducing self-pollen transfer (geitonogamy) and inbreeding through changes in pollinator behavior associated with reduced nectar rewards. Here I experimentally tested the indirect effects of the nectar-robbing bumble bee, Bombus occidentalis, on the distance of pollen movement among plants and levels of pollen movement within plants (estimated using powdered fluorescent dyes as pollen analogues) using the self-incompatible, hummingbird-pollinated host, Ipomopsis aggregata. Empirical results did not fully support the theoretical predictions. Heavy levels of nectar (>80% of available flowers robbed) had no effect on the mean and mean-squared distance of dye dispersal within populations. However, hummingbird pollinators were 50% more likely to depart from a population after visiting a plant with low robbing relative to a plant with high robbing, suggesting that pollen dispersal among populations might be reduced in plants with high robbing relative to plants with low robbing. Heavy nectar robbing reduced levels of self-dye transfer by one-half. However, when I manipulated robbing levels and access to self-pollen, the costs associated with increased robbing and reduced pollinator visitation (e.g., reduced seed production) outweighed any advantages associated with reduced geitonogamy. Taken together, these results suggest that the negative indirect effects of robbing on plant reproduction through decreased pollinator visitation and changes in pollinator departure from plants far exceed any positive effects associated with decreased geitonogamy. Given the widespread nature of plant attack by nectar robbers, these indirect effects are likely common phenomena structuring natural plant populations. Corresponding Editor: T.-L. Ashman

Caddisfly life histories along permanence gradients in high-altitude wetlands in Colorado (U.S.A.) - J. E. Jannot; W. S. Brown; S. A. Wissinger (Freshwater Biology, 2003)
SUMMARY1. Larvae of cased caddisflies (Limnephilidae and Phryganeidae) are among the most abundant and conspicuous invertebrates in northern wetlands. Although species replacements are often observed along permanence gradients, the underlying causal mechanisms are poorly understood. In this paper, we report on the distributional patterns of caddisflies in permanent and temporary high‐altitude ponds, and how those patterns reflect differences in life history characteristics that affect desiccation tolerance (fundamental niches) versus constraints related to biotic interactions (realised niches).2. Species (Hesperophylax occidentalisandAgrypnia deflata) that were encountered only in permanent ponds are restricted in distribution by life history (no ovarian diapause, aquatic oviposition, and/or inability to tolerate desiccation). Although the egg masses ofH. occidentalistolerate desiccation, the larvae leave the protective gelatinous matrix of the egg mass because adults oviposit in water.3. Three species (Asynarchus nigriculus, Limnephilus externusandL. picturatus) have life history characteristics (rapid larval growth, ovarian diapause and terrestrial oviposition of desiccation‐tolerant eggs) that should facilitate the use of both permanent and temporary habitats. However,A. nigriculusis rare or absent in most permanent ponds, andL. externusandL.picturatusare rare or absent in most temporary ponds. Experimental data from a previous study on the combined effects of salamander predation and interspecific interactions among caddisflies (e.g. intraguild predation) suggest that biotic interactions limit each species to a subset of potentially exploitable habitats.4. Many wetland invertebrates exhibit species replacements along permanence gradients, but few studies have separated the relative importance of the effects of dryingper sefrom the effects of biotic interactions. Our results emphasise the complementary roles of comparative data on life histories and experimental data on competition and predation for understanding invertebrate distributions along permanence gradients.

The aquatic insect communities of Holbrook Creek and Cochetopa Creek in Colorado. - Mark Allen Wallace (University of North Texas Digital Library (University of North Texas), 2003)
The first objective for this problem in lieu of thesis project was to gather, identify to the lowest practical taxonomic level and organize all available aquatic insects collected from high altitude Colorado aquatic systems during the summers of 1994, 1996, 1998, and 2002 for the University of North Texas Environmental Science Field Course (BIOL 5650). The curated collection will be housed in the Elm Fork Natural History Museum, located at the University of North Texas. The second objective was to provide a summary and discussion of the occurrence and distribution of the aquatic insects collected from Mt. Blanca in 1994, 1996, and 1998 and to create a taxa list of aquatic insects collected from Cochetopa Creek during the summer of 2002.

Ecological Genetics of Dispersal and Mating Systems in Populations of Yellow-Bellied Marmots (Marmota flaviventris) - C. H. Floyd (2003)

An Addition to the Dinosaur Freeway Megatracksite, Dakota Group (Upper Cretaceous), Bent County, Colorado - B. A. Schumacher (Ichnos, 2003)
A newly discovered dinosaur tracksite in the Upper Cretaceous Dakota Group of southeastern Colorado preserves tracks attributable to ornithopod, theropod, and possibly ankylosaurid dinosaurs. Minimally 79 tracks occur at the site, and are comprised predominantly of ornithopod prints preserved as natural sandstone casts. Nine ornithopod tracks are preserved in situ, and all but one of these trends in a northeasterly direction. The high density of ornithopod tracks coupled with the similar trend of those in situ suggest gregarious behavior. Size distribution of the ornithopod tracks indicates that some juveniles are present, with sub-adults most abundant and lesser numbers of mature adults. Considerable size variation exists within the nine in situ tracks with similar trends. Thus, the site could record the passage of a mixed herd composed of several age classes. This may be the only reported Dakota tracksite where ornithopod, theropod, and ankylosaurid prints occur together.

The evolution of population biology - W. B. Watt (2003)

Reproductive isolation and hybrid pollen disadvantage in Ipomopsis - R. Alarcon; C. A. Wu; Diane R. Campbell (Journal of Evolutionary Biology, 2003)
Abstract One cause of reproductive isolation is gamete competition, in which conspecific pollen has an advantage over heterospecific pollen in siring seeds, thereby decreasing the formation of F1 hybrids. Analogous pollen interactions between hybrid pollen and conspecific pollen can contribute to post-zygotic isolation. The herbaceous plants Ipomopsis aggregata and I. tenuituba frequently hybridize in nature. Hand-pollination of I. aggregata with pollen from F1 or F2 hybrids produced as many seeds as hand-pollination with conspecific pollen, suggesting equal pollen viability. However, when mixed pollen loads with 50% conspecific pollen and 50% hybrid pollen were applied to I. aggregata stigmas, fewer than half of the seeds had hybrid sires. Such pollen mixtures are frequently received if plants of the two species and F1 and F2 hybrids are intermixed, suggesting that this advantage of conspecific over hybrid pollen reduces backcrossing and contributes to reproductive isolation.

Individual differences do not influence flight initiation distance in yellow-bellied marmots (Marmota flaviventris) - A. M. Runyan (2003)

Heart rates of free-ranging yellow-bellied marmots - Kenneth B. Armitage (International Network on Marmots, 2003)

Succession in the Gothic Landslide - A. Ridorf; J. Turk; A. England; E. Bland; K. Garlo; B. J. Wilke; T. E. Schweitzer (2003)

Potential of prey size and type to affect foraging asymmetries in tiger salamander (Ambystoma tigrinum nebulosum) larvae - E. B. Johnson; P. Bierzychudek; Howard Whiteman (Canadian Journal of Zoology, 2003)

Lack of appropriate behavioral or development responses by mayfly larvae to trout predators - C. C. Caudill; B. L. Peckarsky (Ecology, 2003)
Many organisms living in heterogeneous environments alter behaviors or morphology when developing in the presence of predators and subsequently incur associated sublethal fitness costs. Larvae of the mayfly Callibaetis ferrugineus hageni develop in beaver ponds with or without trout predators. We examined the potential sublethal fitness costs of developing in the presence of trout predators by comparing patterns of timing and size at emergence from ponds over two years, before and after manipulating trout densities. In addition, the behavior, timing, and size at emergence of larvae reared in mesocosms were compared between treatments with and without trout chemical cues. Timing of mayfly emergence and adult size was not affected by the manipulation of trout in the field, or by the presence of trout chemical cues in mesocosms. Observations of mayflies in mesocosms provided no evidence that predator cues induced antipredator behaviors, such as reduced activity or increased crypsis. Surprisingly, late instar larvae swam more frequently in the presence of trout cues during the middle of the day, a behavior that could increase their vulnerability to visually feeding predators. Thus, larvae did not exhibit any traits expected to increase survival in the presence of trout cues. The apparently maladaptive responses to trout may result from phylogenetic inertia or conflicting selection pressures encountered when developing in fishless habitats. The evolution of plasticity to trout in Callibaetis may be inhibited by frequent dispersal from fishless source populations.

Butterflies: Ecology and Evolution Taking Flight (2003)

The ecology and evolution of host plant use by the generalist membracid, Publilia modesta - J. S. Reithel (2003)

Effects of herbivory on visitation rates of pollinators and antagonists to Ipomopsis aggregtata - S. Baguskas (2003)

Integrating experimental and gradient methods in ecological climate change research - M. L. Fischer; J. A. Dunne; S. R. Saleska; John Harte (Ecology, 2003)

Adaptive strategies and diversity in marmots (2003)

The distribution of Phellinus tremulae in Populus tremuloides in Western Colorado - T. E. Schweitzer (2003)

Dynamics of immigration into yellow-bellied marmot colonies - Kenneth B. Armitage (Oecologia Montana, 2003)

Optimal foraging in Formica lasiodes and Formica puberula - K. Garlo (2003)

The effect of monocotyledon and dicotyledon plants on soil porosity - J. Turk (2003)

Behavioral responses of yellow-bellied marmots to birds and mammals - Kenneth B. Armitage (Oecologia Montana, 2003)

Selection of leaves by sawflies - A. Ritzdorf (2003)

Social complexity but not the acoustic environment is responsible for the evolution of complex alarm communication - Daniel T. Blumstein (2003)

Wetland aquatic invertebrates of the gunnison and gothic areas - E. Bland (2003)

Adaptive strategies and diversity in marmots - O. A. Schwartz; C. M. Salsbury; Kenneth B. Armitage; Kenneth B. Armitage; Kenneth B. Armitage (2003)

A multivariate search for pollination syndromes among penstemons - J. Hogue; W. S. Armbruster; M. C. Castellanos; P. T. Wilson; James D. Thomson (Oikos, 2003)

Summer snowpatches as high alpine resource sources: assessing potential impacts of climate change - C. Segall (2003)

The effect of food supplementation on juvenile growth and survival in Marmota flaviventris - B. C. Woods; Kenneth B. Armitage (Journal of Mammalogy, 2003)
Abstract We provided 2 social groups of yellow-bellied marmots (Marmota flaviventris) with 2 types of supplemental feed (high and low protein) to test hypotheses about effects of food abundance and quality on juvenile growth rates and survival. Both supplemented litters and reference litters ceased to gain body mass by 2 weeks before hibernation even though supplemented litters had access to supplemental food. Body mass at weaning did not differ significantly between the 2 groups, but supplemented young had significantly higher growth rates (21.4–48.7 g/day) than reference young (24.1–33.3 g/day) and therefore had higher body mass late in the season. Juveniles that received high-protein supplements grew faster than the low-protein group. The addition of high-protein feed did not increase survival; however, juveniles that received low-protein feed were more likely to survive. Juveniles with higher body mass were not more likely to survive. Marmots must reach a critical body mass to survive hibernation and do not appear to benefit from mass gain beyond the critical body mass.

Butterflies: ecology and evolution taking flight - W. B. Watt; Carol L. Boggs (2003)

Minerals of the Gilman District and Eagle Mine:Eagle County, Colorado - William J. Warren; Ed Pedersen (Rocks & Minerals, 2003)
(2003). Minerals of the Gilman District and Eagle Mine: Eagle County, Colorado. Rocks & Minerals: Vol. 78, No. 5, pp. 298-323.

Effect of case removal and increased nutrition on larval development, pupation, emergence time, and sexual selection in a caddisfly (Agrypnia deflata, order Trichoptera) - E. Bruneau (2003)

Energetics of hibernating yellow-bellied marmots (Marmota flaviventris) - B. C. Woods; Kenneth B. Armitage; Daniel T. Blumstein (Comparative Biochemistry and Physiology Part A, 2003)

Pollen transfer by hummingbirds and bumblebees, and divergence of pollination modes in Penstemon - M. C. Castellanos; P. T. Wilson; James D. Thomson (Evolution, 2003)

Heterospecific prey and trophic polyphenism in larval tiger salamanders - R. T. Cargille; T. W. Sacco; J. P. Sheen; A. VanDeusen; E. B. Johnson; Howard Whiteman (Copeia, 2003)
Polyphenisms (environmentally cued polymorphisms) are ubiquitous, yet the specific proximate mechanisms producing alternative morphs are generally not well known. We tested hypotheses for the role of large heterospecific prey in the cannibalistic polyphenism within larval tiger salamanders, Ambystoma tigrinum nebulosum, to determine whether heterospecific prey directly or indirectly influence the production of cannibal morphs. Field surveys suggested, and laboratory experiments confirmed, that macroinvertebrate prey induce cannibals via an increase in body size variation within larval salamander populations. Dietary data and laboratory foraging experiments revealed that cannibals preferred conspecifics even when their capture success was greater on macroinvertebrates. Typical morphs, in contrast, consumed only macroinvertebrate and other prey and never successfully cannibalized conspecifics. Our results support the indirect hypothesis that cannibals are induced via increased body size variation within a population of larvae, as a result of differential consumption of large heterospecific prey, and do not rely on consumption of heterospecific prey once they are cannibals. The cannibalistic polyphenism is one example of phenotypic plasticity in which the functional significance and the proximate mechanisms producing the two morphs are becoming clearer, allowing further study of the molecular and physiological basis of the alternative phenotypes.

Early season arboreal behaviour in yellow-bellied marmots (Marmota flaviventris) - V. Yovovich; Link E. Olson; Daniel T. Blumstein (Oecologia Montana, 2003)

Environmental influences on the phenology and abundance of flowering by Androsace septentrionalis (Primulaceae) - F. Saavedra; W. Lee-Yang; David W. Inouye (American Journal of Botany, 2003)
We studied the timing and abundance of flowering by Androsace septentrionalis L. (Primulaceae), an indeterminate winter annual or short‐lived perennial, in 2 × 2 m plots at the Rocky Mountain Biological Laboratory in Colorado, USA, from 1982 to 2000. Flowers were counted every other day for most or all of the growing season in seven plots in a rocky meadow habitat and nine plots in a wet meadow habitat. The phenology and abundance of flowering were both highly variable, with mean dates of first flowering ranging from 16 May to 12 July and maximum daily counts of flowers ranging from 1 to 1187. Snowmelt date was the primary determinant of timing of flowering. For rocky meadow plots, the previous year's summer precipitation and the current year's average minimum temperature in May had significant effects on maximum number of flowers produced, but no environmental variable we considered was significantly correlated with flower abundance in the wet meadow plots. Length of flowering in individual plots ranged from 2 to 85 d, and many plot‐years had both primary (about 1 mo) and secondary (about 10–12 d) flowering periods. The predicted increase in variability of precipitation accompanying climate change will affect negatively the long‐term abundance and persistence of this species at our study site.

Defensive strategy to nectar robbing Ipomopsis aggregata: floral nectar as a tolerance trait - R. M. Rizo (2003)

Comparing pollen presentation in bee and hummingbird pollinated penstemons - S. J. Keller (2003)

The foraging behavior of bees in response to the floral biology of Frasera speciosa (Gentianaceae) - D. Elmowitz (2003)

Observations on plant choice by foraging yellow-bellied marmots - Kenneth B. Armitage (Oecologia Montana, 2003)

Measuring dispersal in a metapopulation using stable isotope enrichment: high rates of sex-biased disperal between patches in a mayfly population - C. C. Caudill (Oikos, 2003)
Dispersal affects a wide array of ecological and evolutionary processes, but has been difficult to estimate empirically. A 15 Nitrogen stable isotope enrichment technique was used to passively mark all developing Callibaetis ferrugineus hageni (Eaton) mayfly larvae in a beaver pond that had previously been shown to be a patch in a source‐sink metapopulation. After enrichment during the larval stages, dispersal among ponds by adult females was demonstrated by the presence of unmarked females ovipositing in the labeled pond, and marked females in an unlabeled pond. Observed frequencies of marked females suggested incomplete mixing between ponds. In contrast, males rarely dispersed from their natal pond, which was consistent with the unusual mating system in this species – adult Callibaetis are short‐lived, do not feed, and females are sexually receptive immediately after emerging from the larval habitat. The frequent dispersal demonstrated using the stable isotope technique was a critical component of the source‐sink dynamic observed in this metapopulation, and further use of this technique will provide insights into patterns of dispersal in spatially structured habitats.

Sociality and individual fitness in yellow-bellied marmots: insights from a long-term study (1962-2001) - Kenneth B. Armitage (Oecologia, 2003)
It is concluded that female yellow-bellied marmots delay onset of reproduction not because of fitness benefits of foregoing reproduction at an earlier age, but due to the social suppression of reproduction by older, reproductive females, which enhances their own fitness to the detriment of the fitness of young females.

Defining yellow-bellied marmot social groups using association indices - D. D. Nanayakkara; Daniel T. Blumstein (Oecologia Montana, 2003)

Changes in flowering and abundance of Delphinium nuttallianum (Ranunculaceae) in response to a subalpine climate warming experiment - F. Saavedra; Mary V. Price; John Harte; David W. Inouye (Global Change Biology, 2003)
High-altitude and high-latitude sites are expected to be very sensitive to global warming, because the biological activity of most plants is restricted by the length of the short snow- free season, which is determined by climate. Long-term observational studies in subalpine meadows of the Colorado Rocky Mountains have shown a strong positive correlation between snowpack and flower production by the forb Delphinium nuttallia- num. If a warmer climate reduces annual snowfall in this region then global warming might reduce fitness in D. nuttallianum. In this article we report effects of experimental warming on the abundance and flower production of D. nuttallianum. Plant abundance (both flowering and vegetative plants) was slightly greater on warmed than control plots prior to initiation of the warming treatment in 1991. Since 1994 experimental warming has had a negative effect on D. nuttallianum flower production, reducing both the abundance of flowering plants and the total number of flowers per plant. Flower bud abortion was higher in the heated plots than the controls only in 1994 and 1999. Results from both the warming experiment and analyses of unmanipulated long-term plots suggest that global warming may affect the fecundity of D. nuttallianum, which may have cascading effects on the pollinators that depend on it and on the fecundity of plants that share similar pollinators.

The evolution of wing color: male mate choice opposes adaptive wing color divergence in Colias butterflies - J. Ellers; Carol L. Boggs (Evolution, 2003)
Correlated evolution of mate signals and mate preference may be constrained if selection pressures acting on mate preference differ from those acting on mate signals. In particular, opposing selection pressures may act on mate preference and signals when traits have sexual as well as nonsexual functions. In the butterfly Colias philodice eriphyle, divergent selection on wing color across an elevational gradient in response to the thermal environment has led to increasing wing melanization at higher elevations. Wing color is also a long-range signal used by males in mate searching. We conducted experiments to test whether sexual selection on wing melanization via male mate choice acts in the same direction as natural selection on mate signals due to the thermal environment. We performed controlled mate choice experiments in the field over an elevational range of 1500 meters using decoy butterflies with different melanization levels. Also, we obtained a more direct estimate of the relation between wing color and sexual selection by measuring mating success in wild-caught females. Both our experiments showed that wing melanization is an important determinant of female mating success in C. p. eriphyle. However, a lack of elevational variation in male mate preference prevents coevolution of mate signals and mate preference, as males at all elevations prefer less-melanized females. We suggest that this apparently maladaptive mate choice may be maintained by differences in detectability between the morphs or by preservation of species recognition.

Nesting activities of yellow-bellied marmots - Kenneth B. Armitage (International Network on Marmots, 2003)

The evolution of transitions between pollination modes in Penstemon - M. C. Castellanos (2003)

Effects of nectar availability, floral display, and herbivore damage on pollinator visitation rates in Castilleja miniata and Castilleja linariifolia - E. J. Case (2002)

Holarctic marmots as a factor of biodiversity (2002)
Unlike the majority of small mammals and similar to other Marmotini, female reproduction in Marmota flaviventris was characterized by increased progesterone levels during lactation as well as gestation. Elevated levels of progesterone during lactation could be an important component of a feedback mechanism that prevents subsequent ovarian activity and ovulation in this obligate annual breeder. High levels of P4 in non-breeding yearling females suggest that there may be critical priming events in reproduction that occur the year before behavioral estrus. Nipple index is associated with the progesterone cycle and is a good index of breeding or attempted breeding by female marmots. Key-words: progestrone, nipple index, gestation, lactation. Pesztome Y oxeamobpioxux cypkoe, 6 omiuiue om bonbuuncmea npedcmaésumeneii Marmotini, 60 6pema bepemeHHocmu u jakmayuu nadaem codepocanue npozecmepoua 6 Kposu. Tlogbimenue KOHYeHMpaYyuU 3m0zZO ZOPMOHA, No ecel BudUMOCMU, AGNARMCA MeXAHU3MOM, OnpedeNAIOWUM NOdaBReHUe akmuéHocmu AliyeKnemoK u oeyaayuu. Bercoxu ypoeenb P4 y HEPA3MHOHCAIOWUXCA Z2O006ANLIX CAMOK nNodmeepxCOaem, 4MO OHU He CnOcObHet K PasMHOHceHUIO 6 9MOM Bo3pacme, HecMompa Ha Hanuyue y Hux 9cmpyca. Tloxazamenb PAI6UMUA ZPYOHLIX WNC CBAZAH C YUKNOM BbIpabomKU Npozecmepoua u ABAREMCA XOPOULUM UHOUKAMOPOM CNOCOGHOCMU CAMOK K PAIMHOHCEHUN. Kuouveepste ci06ea: npozecmepOH, UHOEKC PAIGUMUR 2PVOHbIX WCeNE3, 6epemennocmp, akmayuan. Résumé Contrairement 4 la majorité des petits mammiféres, mais comme les autres Marmotinl, /a reproduction des femelles chez Marmota flaviventris est caractérisée par une augmentation des taux de progestérone pendant /a lactation ainsi que pendant /a gestation, Des taux élevés de progestérone au cours de /a lactation pourraient constituer une composante importante d’un mécanisme de rétroaction qui prévient une activité ovarienne et une ovulation ultérieures chez cet animal 4 reproduction strictement annuelle. Des niveaux élevés de P4 chez des femelies d’un an non reproductrices suggérent qu’il peut y avoir des événements initlateurs de la repoduction qui se produisent l'année précédant l’oestrus comportemental. L’évolution des mamelons suit le cycle de la progestérone et constitue un bon indice de reproduction ou d'une tentative de reproduction chez Jes marmottes femelles. Mots clés : progestérone, indice de reproduction, gestation, lactation. CYPKU TONAPKTUKUY KAK ®AKTOP BUOPA3SHOOBPA3UA K.6. Apmumetiox, K.E. BuHH-Sdeapdc KOOHLIEHTPALYA TIPOTECTEPOHKA ...

Influence of plant abundance on pollination and selection on floral traits of Ipomopsis aggregata - C. M. Caruso (Ecology, 2002)

Climate-ecosystem interactions in montane meadows - John Harte (2002)

The influence of predatory fish on mayfly drift: extrapolating from experiments to nature - A. R. McIntosh; B. W. Taylor; B. L. Peckarsky (Freshwater Biology, 2002)
1. A knowledge of how individual behaviour affects populations in nature is needed to understand many ecologically important processes, such as the dispersal of larval insects in streams. The influence of chemical cues from drift‐feeding fish on the drift dispersal of mayflies has been documented in small experimental channels (i.e. < 3 m), but their influence on dispersal in natural systems (e.g. 30 m stream reaches) is unclear.2. Using surveys in 10 Rocky Mountain streams in Western Colorado we examined whether the effects of predatory brook trout (Salvelinus fontinalis) on mayfly drift, that were apparent in stream‐side channels, could also be detected in natural streams.3. In channel experiments, the drift of Baetis bicaudatus (Baetidae) was more responsive to variation in the concentration of chemical cues from brook trout than that of another mayfly, Epeorus deceptivus (Heptageniidae). The rate of brook trout predation on drifting mayflies of both species in a 2‐m long observation tank was higher during the day (60–75%) but still measurable at night (5–10%). Epeorus individuals released into the water column were more vulnerable to trout predation by both day and night than were Baetis larvae treated similarly.4. Drift of all mayfly taxa in five fishless streams was aperiodic, whereas their drift was nocturnal in five trout streams. The propensity of mayflies to drift was decreased during the day and increased during the night in trout streams compared with fishless streams. In contrast to the channel experiments, fish biomass and density did not alter the nocturnal nature nor magnitude of mayfly drift in natural streams.5. In combination, these results indicate that mayflies respond to subtle differences in concentration of fish cues in experimental channels. However, temporal and spatial variation in fish cues available to mayflies in natural streams may have obscured our ability to detect responses at larger scales.