Defenders' Experts
Fisher Background and Recovery
Fishers are small carnivores and members of the weasel family. Along with their close relative martens, fishers have been described as some of the most habitat specialized mammals in North America, because of their dependence on old growth forests. Fishers are also one of the rarest carnivores still surviving in the U.S. Rocky Mountains and Northwest. Like other carnivores, fishers play an important role as indicators and regulators of the health of old growth forests. They declined or became extinct in much of their range due to centuries of habitat loss and heavy trapping. Although fishers have rebounded with the regrowth of their forested habitats in the East and Midwest, they remain critically imperiled in their Rocky Mountain and West Coast ranges.
Behavior and Habitat
Next to the wolverine, the fisher is the second largest North American terrestrial mustelid and the only forest carnivore that can regularly kill porcupines, which it dispatches with repeated scratches or bites to the face until its prey collapses from exhaustion.
The fisher (Martes pennanti) depends on mature old growth forests for habitat and these carnivores use large areas of forest with fairly dense canopies, large trees, snags, and downed logs. Much of this habitat has been destroyed by decades of logging and road building, thus the fisher has been in direct conflict with human modification of the landscape. On the other hand, timber companies have a history of supporting fisher research and restoration, because fishers help control porcupine populations and the damage they cause to trees.
Yet even in areas where they are abundant, fishers are extremely secretive and are rarely seen by people. This compounds problems with population monitoring and crafting conservation strategies to restore this imperiled species.
Fisher range and population
Northeast and Midwest
Fisher populations in the Northeast and Midwest United States have rebounded with the regrowth of the deciduous forests in those a reas. Restoration efforts continue in the southern extent of their range, such as a reintroduction effort in Tennessee, but fishers are thriving across much of eastern North America.
Rocky Mountains
In the Rocky Mountains, fishers are reduced to critically low levels. Once part of a contiguous population from the Canada border to Colorado and Utah, fishers are now reduced to northwestern Montana from Glacier National Park to the Idaho border and south to the Bitterroot Mountains, and north-central Idaho up into the Idaho Panhandle. No good estimates of fisher numbers exist for this area.
West Coast
In the West Coast mountains, the "Pacific" Fisher population has declined throughout the majority of its range due to habitat loss and fragmentation. The Pacific fisher was extirpated from Washington State and the northern Sierra Nevada. All that remains of it former range from Canada to California is a small, isolated, reintroduced population in wouthwestern Oregon, and small, native populations in northwestern California and the southern Sierra Nevada.
Protection Status
In 2000, conservation groups petitioned the U.S. Fish and Wildlife Service to protect the West Coast fisher population under the Endangered Species Act (ESA). In April 2004 the USFWS determined that the Pacific fisher is critically imperiled and warrants protection under the Endangered Species Act, but that this protection is precluded by other priorities. Thus, the Pacific fisher is listed as a "Candidate" for ESA protections, which is basically a "waiting room" pending further resources to take recovery actions.
In February 2009, Defenders and three other conservation groups submitted a petition to list fishers in the Northern Rocky Mountains under the Endangered Species Act. Biologists consider fishers to be the rarest carnivore in the Northern Rockies, and may not continue to survive without a targeted recovery program. The U.S. Fish and Wildlife Service denied a previous ESA petition in the 1990’s, due to the belief that fishers were connected across all of North America through fisher populations in Canada, which we now know to be false. Not only are fishers in the Rockies and Northwest U.S. isolated from Canadian populations by more than one hundred miles, the Clearwater area of north-central Idaho was found to contain the remnants of a native fisher population that is genetically distinct from fisher populations elsewhere in North America. Defenders and our co-petitioners seek to protect this population, as well as restoring fishers and their habitat across the region necessary to ensure their survival. The four petitioners include Defenders of Wildlife, Friends of the Clearwater, Friends of the Bitterroot, and Center for Biological Diversity.
Recovery Efforts
Eastern U.S.
Defenders of Wildlife, with the Tennessee-based Extirpated Species Foundation and the Tennessee Wildlife Resources Agency, reintroduced the fisher to Tennessee in October of 2002. Read our press release about this event.
Rocky Mountains
Fishers in Montana and Idaho receive very little attention and few resources. Fishers recently became a focal species for Defenders of Wildlife in this region alongside two other rare medium-sized carnivores, wolverines and lynx. Defenders is actively following fisher research, carefully scrutinizing management decisions affecting fishers and their habitat, and working to build a constituency for this rare and agile forest dweller.
West Coast
An analysis by Forest Service researchers indicates that, in the absence of stronger protection measures, the fisher is likely to become extinct in the southern Sierra within 50 years. Moreover, without connectivity between the two populations, they are vulnerable to stochastic events such as fires that could wipe out an isolated population. While fire regimes and their affect on the fisher remain uncertain, Defenders is working with scientists studying both the southern and northern Californian fisher populations to develop better predictive models which show probable affects of logging and fire on the fisher.
Mesocarnivore Conservation Challenges
Fishers, like many other mid-sized or mesocarnivores, are losing ground. This is due to their large habitat requirements and diverse environmental needs. They face many of the same conservation challenges as large carnivores, yet they lack the charisma to garner support as some of their larger counterparts. In fact, while conservationists have focused much attention on restoring wolves and grizzlies to the northern Rockies, an entire group of smaller, less glamorous and in some cases more hard-pressed predators is quietly being ushered out. These are the midsized forest carnivores, the fisher, marten, wolverine and lynx -- animals that can serve as excellent ambassadors for the last wild places in the American West.
|
|
