Threatened and Endangered Species - Status Reports
Date Published: July 1993
Number of Pages: 108
Washington is one of 15 states constituting the southern edge of lynx (Lynx canadensis) range in North America. Consequently, the historic lynx population has been restricted and relatively small. Lynx are adapted to harsh climates with cold temperatures and deep snows. In Washington this allows them to live in habitat that is not occupied during portions of the year when other carnivores might compete with them for food or space.
Lynx live in boreal forests which occur as small fingers along mountain ridges that extend into Washington from Canada and Idaho. The largest contiguous block of this type of habitat occurs in north-central Washington along the east slope of the Cascade Mountain range. Further south, these habitats become smaller and disjunct making them unsuitable to support resident populations of lynx.
Washington's lynx population is estimated to range from <96 to 191 individuals. Lynx undergo population cycles related to the abundance of snowshoe hares, their principle prey. These cycles occur throughout their range and are typically one to two years behind snowshoe hare popUlation cycles. Cycles may not be as noticeable in the southern extremes of lynx range.
Lynx tend to make relatively long movements in search of new territories during a decline in prey abundance or a peak in the popUlation cycle. This replenishes more moderate or vacant habitats and results in incidental lynx sightings in areas that cannot support resident lynx. This phenomenon has occurred throughout the northern-tiered states including Washington. In the early 1960's, lynx were documented in Whitman and Douglas counties. These are predominantly agricultural areas with almost no lynx habitat characteristics. Incidental sightings continue to occur in the southern Cascades, with sightings as recent as 1991.
While lynx continue to occupy their traditional habitats in Washington, concern for their future has intensified largely due to significant recent and planned habitat alterations and past trapping pressure. Lynx are difficult to census and historic population numbers are limited. However, based on trapper interviews and track sightings by field biologists, lynx densities in northeast Washington appear to have been depressed during at least the past 20 years, with no indication of popUlation increases typical of lynx during favorable years. The most likely causes are extensive timber harvest and high trapping levels in Washington during the mid- 1970's and in British Columbia. Planned timber harvest and associated road construction in formerly primitive areas of the north-central Cascades and in northeastern Washington have elevated concern for lynx populations residing there. Furthermore, there is concern regarding a potential reduction in the number of lynx immigrating from British Columbia. This reduction may further increase the vulnerability of this population.
Due to the compounded effects of forest maturation, past habitat alteration, planned habitat alteration, reduced lynx population in British Columbia to provide immigration of lynx from core populations, and the lack of management plans or monitoring programs to ensure longterm maintenance of lynx habitat, the WDW has determined that the lynx population in Washington is vulnerable. The key consideration for reducing future risks is the level of commitment from the U. S. Forest Service and the WDNR (administrators of 91% of lynx range) to adequately protect habitat for lynx.
It is recommended that the lynx be designated a threatened species in Washington.
Washington Department of Wildlife. 1993. Status of the North American lynx (Lynx canadensis) in Washington: Unpubl. Rep. Wash. Dept. Wildl., Olympia.