A survey of stream amphibian species composition and distribution in the North Cascades National Park Service Complex, Washington State (2005)
Rawhouser AK, Holmes RE, Glesne RS. 2009. A survey of stream amphibian species composition and distribution in the North Cascades National Park Service Complex, Washington State (2005). Natural Resource Technical Report. NPS/NCCN/NRTR—2009/169. USDI National Park Service. Fort Collins, Colorado
The North Cascades National Park Service Complex (NOCA) is located in northwestern Washington State and encompasses 275,684 hectares. It is comprised of three management units: North Cascades National Park, Ross Lake National Recreation Area and the Lake Chelan National Recreation Area. Approximately 93% of this area is managed as federally Designated Wilderness. The region’s wet maritime climate causes high amounts of precipitation, which in turn creates a high abundance and diversity of aquatic resources. Twelve species of amphibians have been documented in NOCA: Ascaphus truei, Pseudacris (Hyla) regilla, Rana aurora, Rana cascadae, Rana luteiventris, Bufo boreas, Ambystoma gracile, Ambystoma macrodactylum, Dicamptodon tenebrosus, Ensatina eschscholtzii, Taricha granulosa and Plethodon vehiculum. A total of 168 stream segments were sampled from nine watersheds across NOCA during two different inventory efforts conducted from 1996-98 and from 2003-04. Two stream obligate amphibians species, A. truei and D. tenebrosus, which require lotic habitats to complete their life cycles, were found in 54% of the stream segments sampled. We found the distribution of A. truei to be widespread across NOCA and within previously established environmental constraints. The site occupancy of this species varied across the east-west precipitation gradient. To the west of the orographic divide, they were found in 75% of the sites surveyed, and on the eastern side they were detected in 37% of the sites surveyed. Our surveys expanded the documented range of D. tenebrosus in NOCA from a previous single sighting near the North Cascades Visitors Center in the Newhalem Creek watershed to thirteen new sites in the Chilliwack and Skagit watersheds. In Canada, D. tenebrosus are only found in the Chilliwack River and Cultus Lake watershed and these findings may be significant for the conservation status of this species since NOCA lands represent the majority of the protected habitat for this isolated British Columbian population.
- Type
- Published Report
- Authors
- Rawhouser, Ashley; Holmes, Ronald; Glesne, Reed
- Date of Issue
- 2009-02
- Publisher
- USDI National Park Service
- Units
- LACH , NOCA , NRSS , ROLA
- Keywords
- Abundance, amphibian inventory, Amphibians, Biodiversity, Distribution, Inventory, Lake Chelan National Recreation Area, North Cascades National Park Service Complex, North Coast and Cascades Network, Pacific Giant Salamander, Presence, Ross Lake National Recreation Area, Stream, Tailed frog, Washington State
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Amphibians and Reptiles