The effects of old-growth fragment area on bat activity in the modified landscape of Olympic National Forest, WA.

摘要

I measured bat activity within a temperate rainforest ecosystem of Olympic National Forest, Washington State, USA, by recording calls in 22 old-growth forest fragments using Anabat detectors. During the summers of 2006 and 2007, I sampled 44 stations within fragments of varying areas and recorded 559 total calls with a minimum of three pulses. I conducted surveys of environmental characteristics within each fragment to determine availability of roosting sites for bats. Bat activity was found to be negatively correlated with isolation, and positively correlated with area above a threshold fragment size. Activity was also associated with old-growth habitat variables for most species groups, although group EPFU/LANO was correlated with characteristics associated with disturbed habitats. My results indicate that most bat species are more abundant in large fragments due to the increased presence of appropriate forest structure for roosting sites available in large fragments.;Keywords. Habitat fragmentation, temperate rain forest, old-growth, Pacific Northwest, insectivorous bats.