AbstractGunnison sage‐grouse (Centrocercus minimus) is a species of special concern and is currently considered a candidate species under Endangered Species Act. Careful management is therefore required to ensure that suitable habitat is maintained, particularly because much of the species' current

Key factor analysis techniques were used to examine factors determining the abundance of a population of non-pest Colias, finding factors resulting in reduced natality and mortality during larval diapause determine the population trends for C. alexandra.

Model and experimental results suggest that, in certain wing regions, increased melanization can reduce body temperature in Pieris; this effect of melanization is exactly the opposite of that found in other Pierid butterflies that use their wings as solar absorbers.

This paper presents evidence of frequency‐size power‐laws in several groups of snow avalanche paths. Other natural hazards, such as earthquakes and forest fires, exhibit similar power‐law relationships. In addition, an analysis of the response of one group of snow avalanche paths to storms through t

Summary The leaf economics spectrum (LES) describes global interspecific correlations between leaf traits. Despite recent theoretical advances, the biological scale at which LES correlations emerge and the physiological and climatic causes of these correlations remains partially unknown. Here, we te

We studied the feeding and positioning periodicity on natural substrates of the overwintering and fast-growing summer generations of a grazing mayfly, Baetis bicaudatus, in a third-order trout stream and a fishless, first-order tributary in western Colorado. At 4-h intervals over 24-h, we recorded t

Carol L. Boggs, Dennis D. Murphy, Community Composition in Mountain Ecosystems: Climatic Determinants of Montane Butterfly Distributions, Global Ecology and Biogeography Letters, Vol. 6, No. 1, Mountain Ecology: Organism Responses to Environmental Change (Jan., 1997), pp. 39-48

The ability of organisms to produce genetic variation for any trait, including resistance to pathogens, is partially determined by breeding system. I used enzyme electrophoresis, crossing experiments, and cytology to assess the breeding systems of cooccurring Arabis species that are often infected b

In some areas of sympatry, reproductively compatible plant species hybridize, but in other areas of sympatry, they do not and they remain reproductively isolated from one another. Explanations offered to explain patterns of hybridization that vary by population have usually focused on genetic or env

The data indicate that bumblebees exhibit great plasticity in foraging behavior and that they are able to forage efficiently under a wide range of environmental conditions.

Yellow-bellied marmots (Marmota jlaviventris) conserve maintenance energy by reducing resting metabolic rate, decreasing conductance, avoiding thermal stress, by an annual cycle of metabolism, and by reducing metabolic rate and conductance following the mid summer molt. Male reproductive strategies

Alarm calling in group-living yellow-bellied marmots is a form of direct parental care and inclusive fitness, broadly defined, is of little importance for the maintenance of alarm calling.

Dawsonite (NaAl (OH) 2 CO 3 ) is relatively abundant (up to 25 percent) as a rock-forming constituent of a zone within the Green River oil shales in the Piceance Creek Basin, Colorado, and also occurs in Pleistocene ash beds, Olduvai Gorge, Tanzania. The mineral is most readily distinguished from ot

Summary Leaf venation networks mediate many plant resource fluxes and are therefore of broad interest to research questions in plant physiology, systematics, paleoecology, and physics. However, the study of these networks is limited by slow and destructive imaging methods. X‐ray imaging of leaf vein

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 site

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, w

Flowers frequently receive both self (S) and outcross (OC) pollen, but S pollen often sires proportionally fewer seeds. Failure of S pollen can reflect evolved mechanisms that promote outcrossing and/or inbreeding depression expressed during seed development. The relative importance of these two pro

W. F. Morris, M. V. Price, N. M. Waser, J. D. Thomson, B. Thomson, D. A. Stratton, Systematic Increase in Pollen Carryover and Its Consequences for Geitonogamy in Plant Populations, Oikos, Vol. 71, No. 3 (Dec., 1994), pp. 431-440

The selective maintenance of gynodioecy depends on the relative fitness of the male‐sterile (female) and hermaphroditic morphs. Females may compensate for their loss of male fitness by reallocating resources from male function (pollen production and pollinator attraction) to female function (seeds a