DISTRIBUTION OF AMPHIBIANS AND REPTILES ALONG THE TRUCKEE RIVER SYSTEM

From 28 May to 22 August 1992, an intensive survey of the amphibians a nd reptiles along the entire length of the Truckee River system was co nducted during drought conditions. The main objective was to determine the current distribution of amphibians and reptiles (especially oblig ate aquatic/riparian species) within this river system. Four amphibian and 8 reptilian species were observed. Of these 12 species, 5 (42%) a re obligate aquatic/riparian species: the western toad (Bufo bores), n orthern leopard frog (Rana pipiens), Pacific chorus frog (Pseudacris r egilla); bullfrog (R. catesbeiana), and western aquatic garter snake ( Thamnophis couchi). Only two species (Pacific chorus frog and western terrestrial garter snake (T. elegans)) were found along the entire Tru ckee River. The distribution of the northern leopard frog appears to b e decreasing and is now restricted to only a small stretch of the rive r. The decreased distribution of the leopard frog in the Truckee is po ssibly due to success of the introduced bullfrog. No Great Basin spade foot toads (Spea intermontana), mountain yellow-legged frogs (R. musco sa), or western pond turtles were observed. Based on the literature an d our knowledge of the local herpetofauna, individuals of these specie s should occur within the Truckee River system. The results of this st udy that indicate declines in amphibian distribution and population si ze correlate with other investigations in the Northwest, other parts o f the United States, and the world.