Project overview: Uncover the impact of human activity, disease, and landscape changes on the endangered Pacific fisher by supporting park staff in monitoring populations throughout Yosemite and surrounding public lands.

How your support helps: Yosemite National Park is home to the elusive, federally endangered Pacific fisher. This small, forest-dwelling mammal faces significant threats from climate-induced habitat loss, largely driven by wildfires.  

Yosemite Conservancy helped launch an ambitious fisher study in 2021 to address the threat of extinction from drought-induced tree mortality and frequent wildfires. Over the past five years, researchers have used GPS collar technology and biological samples to uncover fisher movement patterns post-fire, locate and protect reproductive structures used by female fishers, model the effects of land management on fisher density, understand human impacts on fishers, and monitor current populations.  

These efforts continue to contribute invaluable data necessary to preserve the Pacific fisher in Yosemite and in surrounding public lands. This ongoing project builds on years of research conducted by multiple agencies and will enable land managers to make well-informed management decisions. 

This year: In 2026, park biologists will continue to survey and monitor Pacific fishers using remote cameras and GPS satellite technology. This year, scientists will build on the wealth of information about preferred fisher habitat and contribute valuable data toward innovative fire-management strategies. With your support, we can protect both fishers and local landscapes for generations to come.

Project partners: Yosemite National Park; University of California, Davis; Integral Ecology Research Center; Rocky Mountain Research Station

Sarah Stock

Wildlife Biologist, Yosemite National Park

Project Notes

"This study is urgently needed to fill critical knowledge gaps on fisher habitat use and connectivity in a landscape drastically altered by tree mortality and wildfire."