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Person

James W Cain

Assistant Unit Leader, Research Wildlife Biologist
Email: jwcain@usgs.gov
Office Phone: 575-646-3382
Fax: 575-646-1281
ORCID: 0000-0003-4743-516X

Location
P.O. Box 30003
Dept. 4901
Las Cruces , NM 88003
US
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
Abstract (from http://www.esajournals.org/doi/abs/10.1890/ES15-00266.1): Climate often drives ungulate population dynamics, and as climates change, some areas may become unsuitable for species persistence. Unraveling the relationships between climate and population dynamics, and projecting them across time, advances ecological understanding that informs and steers sustainable conservation for species. Using pronghorn ( Antilocapra americana) as an ecological model, we used a Bayesian approach to analyze long-term population, precipitation, and temperature data from 18 populations in the southwestern United States. We determined which long-term (12 and 24 months) or short-term (gestation trimester and lactation period)...
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The Impacts of Drought on Fish and Wildlife in the Southwestern U.S.
Species that inhabit the arid Southwest are adapted to living in hot, dry environments. Yet the increasing frequency and severity of drought in the region may create conditions that even these hardy species can’t survive. This project examined the impacts of drought in the southwestern U.S. on four of the region’s iconic species: desert bighorn sheep, American pronghorn, scaled quail, and Rio Grande cutthroat trout. Grasping the impacts of drought on fish and wildlife is critical for management planning in the Southwest, as climate models project warmer, drier conditions for the region in the future. Species are known to respond to environmental changes such as drought in different ways. Often, before changes...
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Feral burros (Equus asinus) and horses (E. ferus caballus) inhabiting public land in the western United States are intended to be managed at population levels established to promote a thriving, natural ecological balance. Like many large ungulate populations, management agencies employ aerial surveys to obtain estimates of horse and burro population sizes. Double-observer sightability (MDS) models perform well for estimating feral horse abundances, yet the effectiveness of these models for use in burro populations is less understood and may be different due to the smaller size, stoic behavior, and cryptic pelage of burros. These models help minimize detection bias, yet bias can be further reduced with models that...
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