Aquatic vertebrate assemblages of the Upper Clear Creek Watershed, California

摘要

We sampled streams in the Upper Clear Creek Watershed in northwestern California in Fill 20111 and fall 2005 to document assemblages of aquatic vertebrates and to provide resource managers with information on the importance of these assemblages in tennis of regional biodiversity We used single-pass backpack electrofishing to sample 15 sites in fall 2004 and the same 1.5 sites plus 4 new sites in fall 2005. We captured 10 fish taxa and 2 species of larval amphibians. Seven of the fish taxi were native species. Of the exotic species, only brook trout (Salvelinus fontinalis) occurred at more titan 1 site. Ordinations by nonmetric multidimensional scaling indicated a gradient froze sites with rainbow trout (Oncorhynchus mykiss), Pacific giant salamander (Dicamptodon tenebrosus), and tailed frog (Ascaphus truei) to sites dominated by riffle sculpin (Cottus gulosus), California roach (Hesperoleucas symmetricus), and Sacramento sucker (Catostomus occidentalis). The gradient in species composition was associated with changes in elevation, gradient, discharge, and substrate. The Upper Clear Creek Watershed represents a unique area of overlap between the North Coast California amphibian fauna and the Central Valley fish fauna with a notable paucity of exotic fishes and amphibians. Preservation of the integrity of native aquatic assemblages is an important goal for aquatic resource management in the region; our results provide a critcial baseline to gauge future management actions.