High Lakes -
Amphibian Assemblages and Introduced Fishes in the Wilderness Areas of the Klamath-Siskiyou Bioregion
We are assessing the effects of introduced fish on the distribution and abundance of amphibians in the U.S. Forest Service wilderness areas of Northern California. We are also quantifying the current distributions and habitat associations of fish and amphibians in these high elevation regions.
The alpine and subalpine lentic habitats of northern California support a diverse assemblage of amphibian species including the long-toed salamander and Cascades frog (California species of special concern).
As of the fall of 2001, we sampled 695 aquatic habitats in the Trinity Alps, Marble Mountains and Russian Wilderness. We detected long-toed salamanders at only 40 sites and Cascades frogs at 154 sites.
We used gill nets to assess presence, species and density of fish in the lakes. Of water bodies greater than two meters deep, fish were detected in 80 % of the lakes in the Trinity Alps, 90 % in the Marble Mountains and 100 % in the Russian Wilderness. Because trout have been stocked extensively in lake habitats throughout northern California, little of this habitat remains for native amphibians.
Data from the Trinity Alps, Marble Mountains and Russian Wilderness show a significant negative effect of fish on both long-toed salamanders and Cascades frogs.
