University of Nevada, Reno

About: University of Nevada, Reno is a education organization based out in Reno, Nevada, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 13561 authors who have published 28217 publications receiving 882002 citations. The organization is also known as: University of Nevada & Nevada State University.

Persistence of Different-sized Populations: An Empirical Assessment of Rapid Extinctions in Bighorn Sheep

Abstract: Theory and simulation models suggest that small populations are more susceptible to extinction than large populations, yet assessment of this idea has been hampered by lack of an empirical base. I address the problem by asking how long different-sized populations persist and present demographic and weather data spanning up to 70 years for 122 bighorn sheep (Ovis canadensis) populations in southwestern North America Analyses reveal that: (1) 100 percent of the populations with fewer than 50 individuals went extinct within 50 years; (2) populations with greater than 100 individuals persisted for up to 70 years; and (3) the rapid loss of populations was not likely to be caused by food shortages, severe weather, predation, or interspecific competition These data suggest that population size is a marker of persistence trajectories and they indicate that local extinction cannot be overcome because 50 individuals, even in the short term, are not a minimum viable population size for bighorn sheep.

Recurrent evolution of herbivory in small, cold-climate lizards: Breaking the ecophysiological rules of reptilian herbivory

Abstract: Herbivory has evolved in many groups of vertebrates, but it is rare among both extinct and extant nonavian reptiles Among squamate reptiles, (lizards, snakes, and their relatives), 7,800 species are considered to be herbivorous, and herbivory is restricted to lizards Here, we show that within a group of South American lizards (Liolaemidae, ≈170 species), herbivory has evolved more frequently than in all other squamates combined and at a rate estimated to be >65 times faster Furthermore, in contrast to other herbivorous lizards and to existing theory, most herbivorous liolaemids are small bodied and live in cool climates Herbivory is generally thought to evolve only in reptile species that are large bodied, live in warm climates, and maintain high body temperatures These three well known “rules” of herbivory are considered to form the bases of physiological constraints that explain the paucity of herbivorous reptile species We suggest that the recurrent and paradoxical evolution of herbivory in liolaemids is explained by a combination of environmental conditions (promoting independent origins of herbivory in isolated cool-climate regions), ecophysiological constraints (requiring small body size in cool climates, yet high body temperatures for herbivores), and phylogenetic history More generally, our study demonstrates how integrating information from ecophysiology and phylogeny can help to explain macroevolutionary trends

Antecedents of organizational knowledge sharing: a meta‐analysis and critique

Abstract: Purpose – Knowledge is the most important component of sustainable organizational growth and economic performance. This meta‐analysis aims to summarize the determinants of individuals' knowledge sharing (KS) intentions and behaviors in organizations.Design/methodology/approach – The authors organize the knowledge sharing antecedents investigated in 46 studies (n≈10,487, median n=172) into three categories, i.e. knowledge sharer intention and attitude (four variables); rewards for KS (three variables); and organizational culture (nine variables).Findings – Variables in all three antecedent categories positively contribute to KS intentions and behaviors; high between‐study variability exists, and the fail‐safe n statistic suggests the observed effects are robust against a “file drawer” (missing study) bias. Moderator results suggest that motivating KS is easier in collectivist, as opposed to individualist, cultures.Research limitations/implications – In most of the studies included in this meta‐analysis, pa...

Patterns of apparent extirpation among isolated populations of pikas (ochotona princeps) in the great basin

Abstract: We conducted exploratory analyses to examine the relative roles played by natural and anthropogenic influences on persistence of a montane mammal. We revisited historical locations of pikas (Ochotona princeps) within the hydrographic Great Basin during summers of 1994–1999. Seven of 25 populations (28%) reported earlier in the 20th century appeared to have experienced recent extirpations. We assessed causative agents of faunal change using several alternative, but not mutually exclusive, hypotheses. Higher probability of persistence was correlated with greater area of talus habitat at local and mountain-range scales, higher elevation, more easterly longitude, more southern latitude, lack of livestock grazing, greater distance to primary roads, and wilderness management. However, only area of habitat in the mountain range, maximum elevation of talus habitat, and distance to primary roads appeared in the most parsimonious model of persistence when we used Akaike's information criterion model-select...