A shy and elusive member of the weasel family, the Pacific fisher seems misnamed. This carnivorous inhabitant of mid-elevation forests in the Sierra Nevada doesn't fish at all, favoring birds, small mammals and -- unlike most predators -- even porcupines in its diverse diet that they augment with fungi and fruit. Feeding mostly in the hours around dusk and dawn, fishers are seldom seen by humans. Chances are that few, if any, readers have ever seen one.
Distribution of the Pacific fisher once ranged from British Columbia southward to California's Sierra Nevada. Its historic range has shrunk by about half, leaving only two native populations in California, one around the western California/Oregon border and the other in the southern Sierra. Although laws passed in the 1940s banned the trapping of Pacific fishers, the loss of forest habitat to development and logging, along with the species' low reproductive capacity, their diminished genetic diversity, disease and roadkills in places such as Yosemite, has put the fisher population in peril. It is now a candidate species for listing under the federal Endangered Species Act and a California species of concern.
Like all predators, Pacific fishers provide a vital service in controlling prey populations, and their extinction would further rattle the natural balance between the two ecosystem players. Their loss, in the words of one researcher, would be a "tragedy."
Partly to address this issue, the Sierra Nevada Adaptive Management Project (SNAMP) was created through a joint agreement by the University of California, Berkeley, with federal and state agencies in 2005 to develop a management and monitoring plan consistent with the U.S. Forest Service's Sierra Nevada Forest Plan Amendment. One of the project's aims has been to study the ecological status of the fisher population and their habitat needs, and to develop management recommendations to facilitate their recovery.
Rick Sweitzer, Ph.D., the lead project scientist of the SNAMP fisher team, will discuss this project and describe the fisher's natural history in a slide presentation, "Ecology of the Rare Pacific Fisher in the Sierra Nevada," at the Yosemite Area Audubon Society's monthly program at 7 p.m. Thursday, March 14, at the Oakhurst Methodist Church, 49223 Road 426.
Sweitzer is an adjunct associate professor at the Center for Natural Resources in the Department of Environmental Science, Policy and Management at the University of California, Berkeley. He earned his Ph.D. in Evolution and Conservation Biology at the University of Nevada, Reno, after receiving a B.S. in Biology and Environmental Science at Northern Arizona University and an M.S. in Wildlife Ecology from Nevada, Reno. With emphasis in mammalian ecology and conservation biology, he has more than 25 years of experience in wildlife biology research, ranging from bison to bald eagles to wild pigs.
Sweitzer's presentation is open and free to the public, although donations to defray program costs and to support the chapter's local activities are appreciated. Refreshments will be available. Details: (209) 742-5579 or (209) 966-2547 or visit www.yosemiteaudubon.org.