The U.S. Fish and Wildlife Service (FWS) announced yesterday its proposal to list the West Coast population of the fisher (Pekania pennanti) as a threatened species under the Endangered Species Act (ESA). The scientific community, the public, and interested stakeholders have 90 days in which to submit comments to the FWS, which the agency will use to assess the threats to the fisher in each part of its range in California, Oregon, and Washington. Public comments are due no later than January 5, 2015.

Fishers are small mammals that live in low- to mid-elevation forests and utilize snags, hollow trees, and cavities in trees for rearing their young and for security from predators. Apart from a small, reintroduced population on the Olympic Peninsula in Washington, the fisher occupies parts of California and southwest Oregon.

Threats Identified by the FWS

The proposed listing references several threats to the fisher, but focuses on three in particular, as follows.

• Habitat loss and change due to wildfire and fire suppression activities. The FWS notes that fire regimes vary widely across fisher-occupied areas of California, Oregon, and Washington, and thus, the effects of wildfire vary geographically. According to the FWS, severe fires can remove suitable habitat for decades, if not permanently, and can also cause shifts in home ranges and movement patterns, increase predation, and create barriers to dispersal, especially where populations are connected only via narrow corridors. The proposed rule also states that fire suppression techniques such as backburning, fuel breaks, and snag removal, result in the removal of fisher habitat. The FWS considers wildfire and fire suppression to be a threat to fisher habitat now and in the future because the frequency and size of wildfires are expected to increase.
• Rodenticides. The proposed listing alludes to recent research documenting fisher fatalities due to rodenticides, particularly in the California populations. Legal applications of rodenticides are not the likely source. Large quantities of rodenticide have been found at illegal marijuana cultivation sites within fisher habitat. Rodenticide exposure has also been found in the reintroduced Olympic National Park population in Washington, but it is not clear whether the animals were exposed in Washington or in British Columbia prior to translocation. In addition to fatalities, sublethal exposure to rodenticides can cause sicknesses which increase the probability of mortality from other sources. Rodenticides are considered a likely threat to fisher populations, but more research is needed regarding population-level effects.
• Timber harvest practices in certain areas. The proposed rule explains that the effects of timber harvesting vary greatly, based on the type of timber management practice employed, and where it occurs. According to the FWS, timber harvesting may pose a threat to the fisher, and, where fisher populations exist in narrow bands or where suitable habitat is fragmented, the FWS states that timber harvesting may decrease connectivity between population pockets. In areas of Washington and Oregon where fisher populations have been reintroduced, timber harvesting is less of a concern because habitat occurs in large contiguous blocks. The FWS notes that areas managed under the Northwest Forest Plan are already being managed in ways that benefit the fisher.

In addition, the proposed listing also finds “small population size” to be a threat, in the sense that chance events present an increased risk of extinction to small, isolated populations. Climate change is currently not viewed as a threat, because it is not yet clear how climate change may affect fisher habitat. The FWS considers the “cumulative and synergistic effects” of alterations to habitat, rodenticides, stressors associated with climate change, and human development to pose a threat to fishers, but that the degree and type of threat varies widely across the sub-regions and populations.

Applicability of a 4(d) Rule

The FWS is not currently proposing a rule under section 4(d) of the ESA, but is seeking public comment on the applicability of such a rule to the fisher species. Under section 4(d), the Secretary of the Interior may modify the standard protections for a threatened species with measures tailored to its specific conservation needs. The notice of proposed listing states that the FWS is seeking “data that support various management actions and regulations that could be utilized to develop at potential 4(d) rule necessary and advisable to provide for the conservation of fisher, should it be listed as a threatened species.” Therefore, if the fisher is listed as a threatened species, it is possible that the FWS will also issue a proposed 4(d) rule.

Potential Alternative DPSs

The presently proposed West Coast distinct population segment (DPS) includes fisher within California, Oregon, and Washington. However, the FWS has noted that smaller areas within the larger DPS boundary would also potentially constitute a valid DPS. In particular, the FWS is seeking input on two proposed alternative DPSs. The first would be a single, smaller DPS encompassing all the fisher of California and southern Oregon. The second alternative would entail two narrowly drawn DPSs, one comprising the California population plus that of far southwestern Oregon, and the other a distinct pocket entirely in Oregon.

Designation of Critical Habitat

The proposed listing indicates that the designation of critical habitat is “not determinable” at this time. The agency notes that consideration of the impacts of such a designation cannot be determined until the DPS(s) are first determined in the final rule.

Link to Federal Register publication: http://www.gpo.gov/fdsys/pkg/FR-2014-10-07/pdf/2014-23456.pdf