Recovery Plan for the Northern Spotted Owl - DRAFT

few meters from water after heavy rains, but this is unusual (Nussbaum et al.1983). Corn and Bury (1989) compared four species of aquatic amphibians in23 streams in uncut forests versus those in forests logged 14 to 40 years ago,in the central part of the Oregon Coast Range. The density and biomass of thefour species (including Rhyacotriton spp.) was significantly higher (2-7X) in thestreams of uncut forests, because streams in logged stands generally possessedsmaller substrate material, caused by increased sedimentation. WhereRhyacotrton spp. occur in and adjacent to small headwater streams, theirexistence is threatened by timber harvest (Bury and Corn 1988b).Rhyacotriton spp. are fairly widespread in the Pacific Northwest and are mostlikely to occur in or adjacent to higher order, cold streams in forested areas.Because of the requirement for permanently cold water in smaller streams,Olympic salamanders are highly susceptible to forest practices that removecanopy cover and elevate water temperatures (Beatty et al. 1991).Tailed Frog (Ascaphus tie)Distribution and habitat.-Tailed frogs are found west of the crest of theCascade Range from British Columbia to northwestern California. They arealso found in extreme northwestern Oregon, southwestern Washington,northern Idaho, and northwestern Montana. Tailed frogs may be found fromsea level to over 2,000 meters. They are usually found near or in fast-flowing,permanent streams in forests. The tadpoles of the tailed frog are uniqueamong northwestern larvae because their oral disc is modified into a suckingorgan that enables them to cling to rocks in swift current. In the Oregon CoastRange, Gomez (1992) found tailed frogs to be most abundant in riparian areasof mature- and old-growth forests as compared to upland sites and young anddeciduous forests.Ecology and management.-Adults eat a wide variety of invertebrates includingsnails, ticks, spiders, mites, and numerous insect species (Nussbaum et al.1983). Pacific giant salamanders (Dicamptodon) are a major predator of A. trueitadpoles (Metter 1963, Duellman and Trueb 1986). Populations of A. tnuei maybe decimated by natural disasters such as floods that greatly reduce larvalpopulations (Metter 1968).Ascaphus truei is probably the amphibian most likely to be affected by oldgrowthhabitat loss and habitat destruction. Tailed frogs are closely associatedwith fast-flowing streams in forested areas and are commonly found within oldgrowthforests (Bury 1983, Bury and Corn 1988a and 1988b, Raphael 1988,Welsh and Lind 1988, Corn and Bury 1989). Bury (1983) found A. truei onundisturbed old-growth sites but none in logged areas. Bury and Corn (1988)bconsidered A. tnrei to be 'sensitive to timber harvest" and that the survival ofthis species may depend upon protection of cool flowing streams that thespecies requires for breeding purposes and larval development. In loggedstands, tailed frogs are most often found in streams where uncut timber stillremains upstream (Corn and Bury 1989). Tailed frogs are likely to be affectedby increased water temperature that occurs after clear-cutting (Bury and Corn1988b).Because of the extreme philopatry and tendency for A. truei populations to beextremely disjunct (Daugherty and Sheldon 1982), recolonization after localextinction may take a relatively long time. Therefore, some populations maynot recover from habitat destruction.396