Threats

Special status species and habitats are often sentinels of accelerated ecosystem change and, by definition, are priorities for protection, restoration, or focused management.

Many species of amphibians and reptiles are declining or facing population threats in the West related to habitat loss, habitat alteration, introduction of non-native species, and other factors. Our work focuses on the status and trends of resident herpetofauna and how to better manage their habitats. Much of the effort is undertaken with cooperators, particularly with other agencies in the...

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.

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.

USGS WERC’s Dr. Karen Thorne, her team of reseachers, and her partners are currently taking a local site network approach to describe current and future conditions and projected responses of coastal ecosystems to sea-level rise and other stressors. The Coastal Ecosystem Response to Climate Change (CERCC) program’s goal is to understand how ecosystems vary in their ability to keep up with sea-level...

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...

This project improves our understanding of the ecology of amphibians in northern California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of amphibians to understand factors that affect where amphibians are found and how populations change. He further explores the relationships of amphibians with...

Dr. Kathleen Longshore’s goal is to understand how predator/prey relationships, disease and human-caused disturbance work separately and synergistically to impact bighorn sheep populations under variable ecological stress. Information from this project will provide managers with an understanding of specific and regional impacting factors that contribute to impact variation in population trends.

The Ridgway’s rail is a federal and state listed endangered species that occurs in wetlands along the Pacific Coast and from the Lower Colorado River drainage to southern Baja California. Three subspecies of Ridgway’s rail are found within the United States: the California Ridgway’s Rail, Yuma Ridgway’s rail, and Light-footed Ridgway’s rail. All three subspecies have declined since 1900 as a...

Sea otters are crucial indicators of the health of our nearshore waters and coastal resources, from kelp forests to fisheries. What clues does the sea otter's decline hold for our knowledge of ecosystem and global change? WERC's sea otter team and U.S. and Canadian researchers have teamed together to investigate. Relevance to USGS Missions: This research project has direct relevance for the...

WERC's sea otter researchers are developing and utilizing a variety of methodological and analytical tools to understand the causes of biological and ecological trends in sea otter populations, and to predict the ecological consequences of management practices on these populations and their ecosystems.

Riparian woodlands are highly productive ecosystems that support a disproportionately high fraction of regional biodiversity. They are also one of the most endangered terrestrial systems in temperate North America, and have been reduced to just 5% of their former extent in California and throughout the American southwest. These losses have been accompanied by steep declines in numerous plant and...