boreal toad

Forecasting population responses to natural and anthropogenic stressors is a fundamental challenge for ecologists, conservation biologists, and wildlife managers. Predicting amphibian population trajectories, in particular, poses an additional challenge because different life-stages (e.g. aquatic larva, terrestrial adults) rely on highly disparate resources, making it difficult to predict the life-stage(s) at which the effects of stressors may manifest.

Carl Brown holding a Black Rosy Finch

A species that forages on snowfields and tundra during the breeding season, the Black Rosy-Finch is an alpine breeding obligate that uses cracks in cliff faces for nesting sites.

Island Scrub-Jay, bishop pines, Santa Cruz Island

The Island-Scrub Jay, Aphelocoma insularis, has been the focus of demographic research since 2008. Our work is motivated by threats to the species viability posed by its limited range and population size, and seeks to understand the factors that determine the distribution and abundance of A. insularis on Santa Cruz Island.

Understanding the mechanisms driving variation in movements, habitat selection, and demography for Great Gray Owls is critical for the development of effective conservation strategies for this state-sensitive species.

Bats provide ecosystem services that benefit the human economy and agriculture. Many bat species across the US are in population decline due to the degradation of natural roosting habitat, wind energy development, and the effects of white-nose syndrome (WNS).  The northern long-eared bat (hereafter NLEB) has suffered catastrophic population losses in portions of its range with the arrival of White-nose Syndrome, a disease caused by the fungus Pseuodgymnoascus destructans (Pd).

Brewer's sparrow nestlings

This project investigates the effects of habitat alteration from energy development on songbird nest success. We aim to identify the relationship between nest predation rates and small mammal abundance, and examine possible mechanisms driving the increased abundance of rodent nest predators.

Completed Projects

Alpine ecology and climate change

Rapid climate change is one of the defining conservation issues of the 21st century. The effects of changing conditions are seen in most of the biomes on earth and influence all levels of ecological hierarchy – from individual species behavior to entire ecosystem processes.

Spatially isolated populations of species, especially those with limited mobility, are at an increased risk of extirpation. Though Columbia spotted frogs (Rana luteiventris) have a widespread range throughout western North America…

Mountain Pine Beetle Epidemic Impacts on Wildlife

Lodgepole pine (Pinus contorta) forests of the Intermountain West are currently experiencing a widespread epidemic of the mountain pine beetle (Dendroctonus ponderosae), due in part to climate change.

Deer mouse, Thunder Basin National Grassland (photo: Tiff Shao)

Invasive species are one of the most significant threats to native flora and fauna worldwide. Habitat alteration by invasive plants can have direct and indirect effects on fitness with consequences for populations and communities of native wildlife. Small mammals are an integral component of many ecosystems, however, the effects of invasive plants on small mammals are poorly understood. This study addresses a critical information need by determining how small mammal populations and communities respond to habitat alteration by cheatgrass (Bromus tectorum), a widespread invasive plant in North America.


Distinctive life-history traits of the pika such as their sensitivity to temperature, limited dispersal ability and occurrence in small isolated populations render them particularly vulnerable to climate change.

Photo courtesy of blm.gov

The Powder River Basin of Wyoming has undergone extensive energy development in recent decades. We analyzed a 9-yr dataset of over 3,000 nests of 18 raptor species to determine the trends in nest site use between 2003-2011 and to test for any influence of energy development on nest site use.

sage-grouse umbrella

The umbrella species concept holds promise as a shortcut to broad-reaching wildlife management and conservation. In this project, we assessed whether dozens of at-risk wildlife species benefit under the umbrella of sage-grouse conservation efforts in Wyoming, and why.

Wind Energy and Grassland Birds Project

Anthropogenic disturbances can lead to wildlife population declines due to habitat loss and changes in habitat quality. Understanding wildlife responses to these changes can aid us in mediating impacts to wildlife.