The Pacific pond turtle (Actinemys [= Clemmys] marmorata) inhabits a variety of lotic and lentic habitats, including altered habitats such as small reservoirs and other impounded waterways. We determined the distribution and habitat use of the Pacific pond turtle along a 14.8-km-long reach of the Russian River, Sonoma County, California. The study area included a seasonal dam that creates an approximately 5.1-km-long reservoir (the Wohler Pool) with an area of about 360 ha. Basking turtles often used living downed trees with trunks of moderate size, averaging 20.7 cm. Turtles of many sizes were found, including a number of small-sized individuals, indicating some recent recruitment into the population. Turtles also were distributed into a broad range of age classes, including 26.9% juveniles (<120 mm CL, 1-5 yrs old). Pacific pond turtles are resident of the Wohler Pool, but their numbers decreased downstream closer to the dam. Important factors in the persistence of turtles in the Wohler Pool are probably the presence of a temporary impoundment and the gradual effects of the reservoir from upstream to downstream.
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