Oral Session #36: Conservation
of aquatic systems: Ecology and ecotoxicology. Presiding: R. Lathrop.
Tuesday, August 7, 2001. 1:00 PM to 5:15 PM. Hall of Ideas H.
MARY POTEET1.
University of California at Berkeley 1
ABSTRACT- A large body of work provides compelling evidence that anthropogenic impacts can alter human epidemiology and adversely affect public health. Although just as likely to occur, less is known about the impacts of anthropogenic disturbances on parasitism in wildlife. Given that parasites can strongly affect host populations, it is essential to understand how parasitism responds to human impacts such as landscape alterations and climatic change. In this study, I assess how parasitic infection changes in stream communities following clear-cut logging and ask which factors associated with logging drive these changes. I study the parasitic trematode, Cephalouterina dicamptodoni,that obligately and sequentially infects Pacific giant salamander larvae, Dicamptodon tenebrosus,aquatic snails, Juga silicula,and stonefly nymphs, Calineuria californica. Over two months, I censused parasite presence and intensity in each host species from 11 streams in logged watersheds and 7 streams in unlogged watersheds. Parasite intensity and prevalence decreased significantly in each host species following logging. In logged streams, parasite populations were positively related to snail density and pool:riffle ratio, but were inversely related to water temperature. In unlogged streams, parasite populations were positively related to salamander density, but were unaffected by abiotic factors. These data suggest that the relative roles of abiotic and biotic factors affecting parasitism switch following logging and that the reservoir host for the parasite switches from snails in unlogged streams to salamanders in logged streams. These data also provide insights into how human impacts alter parasite dynamics and disrupt host-parasite systems.
KEYWORDS- disease, forestry, amphibian, oregon
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