9701128 Sousa Though many studies have addressed the impacts of anthropogenic disturbances on free-living species, few have considered how these impacts might disrupt the tight links between parasites and their hosts. In this study the PIs investigate the impacts of logging-induced disturbance on the density and distribution of a suite of stream-dwelling species and ask how these changes can alter dynamics of their shared trematode parasite. The trematode parasite, Cephalouterina dicamptodoni, obligately and sequentially infects larval Pacific giant salamanders (Dicamptodon tenebrosus), a common aquatic snail (Juga silicula) and a nymphal stonefly (Calineuria californica). This study consists of three phases: 1) documentation of the effects of logging on the density and distribution of each host species; 2) examination of the patterns of parasite prevalence and abundance within each host species from both logged and unlogged streams; and 3) experimental investigation of the hypothesis that disturbance-induced changes in host distributions and densities alter parasite transmission processes and in turn parasite population dynamics. This work is the first to explore the impacts of logging on both patterns and mechanisms of parasite-host interactions.
