In Washington, this species is poorly known and probably rare. Loss of large decadent trees and snags is likely an important threat.
Description and Range
Keen’s myotis is one of three similar long-eared Myotis species in Washington, making simple field identification impossible in western Washington and southwestern British Columbia (Burles and Nagorsen 2003). Keen’s myotis are largely restricted to moist coastal forests of lower elevations dominated by western hemlock, Sitka spruce, and other conifers, although a few records come from urban sites (Firman et al. 1993, Burles and Nagorsen 2003, Boland et al. 2009a). Keen’s myotis roost in caves, rock crevices, large trees, snags, and buildings (Burles and Nagorsen 2003, Boland et al. 2009a). Hibernacula are known to include mid-elevation caves.
Keen’s myotis has one of the smallest distributions of any North American bat, occurring in coastal areas from southeast Alaska to the Olympic Peninsula, Puget Sound, and Mt. Rainier in Washington (Burles and Nagorsen 2003, Boland et al. 2009a; WDFW WSDM database). They have been reported in five counties in Washington. Population size and trends are unknown (NatureServe 2009). They are generally considered rare, but problems with field identification complicate efforts to assess populations. Low densities have been reported in British Columbia (Firman et al. 1993, Burles and Nagorsen 2003) and southeast Alaska (Boland et al. 2009b). No roosts of this species are currently known in Washington. The last confirmed detection in the state was in 2008.
Threats or potential threats include loss and fragmentation of habitat caused by clearcutting of old-growth coastal forests and human development; disturbance of hibernacula and maternity sites through human visitation and logging road construction; predation by cats; and pesticide use in forests (Burles and Nagorsen 2003, NatureServe 2009).
Sensitivity to climate change
Keen's myotis is a relatively poorly known species, especially in Washington, thus its vulnerability to climate change is difficult to judge. It has a small geographic distribution in the state and is probably mostly restricted to moist coastal forests. The few known hibernacula (all from elsewhere in the range) occur in mid-elevation caves, suggesting that low-elevation caves may to be too warm for hibernation. Moths and spiders comprise a sizeable part of the diet, but a variety of other insects are also eaten. Warmer temperatures and changes in precipitation patterns may negatively affect roosting conditions and prey availability for the species, but this remains speculative.
Exposure to climate change
- Increased temperatures
- Changes in precipitation