Amphibians of the Fort Lewis Military Reservation, Washington: Sampling techniques and community patterns

The 27,000 ha Fort Lewis Military Reservation is situated in the Puget lowlands and contains a wide variety of aquatic habitats offering potential refuge for native amphibians. We surveyed amphibians on Fort Lewis from 1992 through 1995 to examine occupancy patterns relative to wetland characteristics. We documented 9 native amphibians and 1 introduced anuran (Rana catesbeiana) that represent 133 new locality records. We found no Rana pretiosa, but historic records suggest they were present earlier. Bufo boreas was rare. All other species appeared widespread and abundant. Native species richness was highest in temporary wetlands and in wetlands with extensive emergent vegetation. Richness was unrelated to wetland size, distance to nearest neighbor, and the presence of R. catesbeiana or exotic fish. Of four survey techniques used, funnel trapping yielded the most detections, but only visual encounter surveys detected every species.