Biological Threats Research Program
Biological Threats Research Program
Biological threats to wildlife can come from diseases, parasites, or invasive species, and can cause sweeping changes across important ecosystems. WERC scientists lead studies that investigate the source and effects of biological threats to environments across California, Nevada, and Pacific islands. Our projects include informing the restoration of ecosystems, for example by investigating effects and control of invasive plant or animal species concurrent with understanding factors that enhance native species, or discerning the role of natural predators in complex food webs that can control parasites infections in wildlife and humans. Click on the projects below to learn more.
Filter Total Items: 15
Newly-introduced fringe-toed lizard species found in Ventura County, California
A fringe-toed lizard ( Acanthodactylus cf. boskianus ) not native to California was discovered in Ventura County, California on October 14, 2023. This is the first documented occurrence of the species outside its home range (Kraus 2009; Kraus, pers. Comm.). While the source of its introduction is yet to be confirmed, it’s suspected that it has been introduced to Ventura County via the pet trade.
Polar Bear Health and Disease Diagnostics
In 2012, scientists noticed that nearly a third of polar bears sampled in a study in Alaska were suffering from hair loss and poor health. Drs. Lizabeth Bowen and A. Keith Miles of WERC used new technology to track down and identify the factors responsible for driving disease in Alaskan polar bears.
Developing Physiological Diagnostics for the Desert Tortoise
The Mojave desert tortoise is listed as “threatened” under the Endangered Species Act and faces threats from habitat loss, predators, and disease. Drs. Lizabeth Bowen and A. Keith Miles with WERC are designing new methods to determine the type and influence of stressors present in the environment for the tortoise and other wildlife.
Ecology of Infectious Diseases
The public is most familiar with parasites' role in spreading infectious diseases to people and domestic animals. In tropical developing countries, malaria, schistosomiasis, and other infectious diseases cause significant human suffering. While most related studies focus on treating patients, Dr. Kevin Lafferty is studying how ecology of the local environment affects transmission of infectious...
Aridlands Disturbances and Restoration Ecology
Desert landscapes are rapidly changing due to increases in invasive plant species, frequency of wildfires, urban and energy development, recreational use, military training, and climate variation. Dr. Todd Esque, USGS researchers, and collaborators are working together to investigate these changes and provide managers with key information that can be used to manage natural resources more...
Bat Research in California
The primary goal of this bat research program is to develop projects that increase our understanding of basic ecology and natural history of western bat species, while simultaneously providing needed data to inform conservation measures and management decisions in the West. Dr. Brian Halstead, together with Gabriel Reyes, studies the habitat and resource selection, movement ecology, demography...
California Sea Otter Stranding Network
The California Sea Otter Stranding Network is part of the USGS effort to monitor southern sea otters (Enhydra lutris nereis) and provide data to the U.S. Fish and Wildlife Service. WERC's sea otter team works with multiple institutions and partners to report, recover, and examine stranded sea otters. In addition, instructions on how to report a stranded sea otter are included in this webpage.
Contaminants in Waterbirds and Effects on Avian Reproduction
California’s Central Valley and San Francisco Bay Estuary have a long history of mercury contamination from past mercury mining and gold extraction. Waterbirds are particularly susceptible to mercury because of their use of wetland habitats where methylmercury (the most toxic and biologically available form) is produced and relatively low methylmercury exposure can reduce reproductive success...
Desert Tortoise Ecology, Health, Habitat, and Conservation Biology
The desert tortoise is listed as “threatened” under the Endangered Species Act. USGS WERC scientists, along with project partners have been conducting long-term analyses on how changes in the southwestern deserts of the United States can affect desert tortoise populations. Dr. Todd Esque and his team are investigating how habitat disturbances and restoration projects influence tortoise populations...
Detection, Attribution, and Interpretation of Forest Changes
Dr. Nathan Stephenson and colleagues seek to determine what changes are occurring in forests, why they are occurring, and what they mean. For example, they have documented a long-term, apparently climatically-induced increase of tree mortality rates in otherwise undisturbed old forests across the western U.S., implying that these forests could become net sources of atmospheric carbon dioxide.
Mercury Bioaccumulation in Wetlands
Wetlands provide numerous ecosystem services, but also can be sources of methylmercury production and export. Click the next tab to learn how WERC's Dr. Josh Ackerman is evaluating the ecological factors that drive contaminant bioaccumulation in wetland-dependent fish and wildlife.
Process-based Approaches for Ecological Restoration of Degraded Drylands
Surface disturbances ranging from military training, recreation, energy exploration and development, and wildfires impact a large majority of federal lands in the western US, but the ecological and economic impacts are poorly understood. Explore this webpage to learn how Dr. Lesley DeFalco and her research team are currently evaluating and refining conventional approaches for post-fire restoration...