OREGON STATE UNIVERSITY

mark-recapture analysis

Short-term Relationship of Timber Management and Pacific Giant Salamander Populations, and the Response of Larval Stream Amphibian to Predators Under Different Sediment Levels
Leuthold, N.
Mar-02-2010

In the Pacific Northwest, multiple studies have found negative effects of timber harvest on stream amphibians, but the results have been highly variable and region-specific. Over the last 30 years forest management practices have changed substantially, yet little work examines how modern forest management relates to the abundance or density of stream amphibians. I examined the influences of contemporary forest practices on Pacific giant salamanders as part of the Hinkle Creek paired watershed study. Density was positively associated with substrate, negatively associate with upstream area drained, and had a weak positive association with fish density, but I found no evidence of an effect of harvest. Pacific Northwest stream amphibians are often negatively associated with sedimentation, but the mechanism underlying this relationship is not clear. I found amphibian larvae were more visible as sediment level increased and some evidence that larvae were less visible in the presence of fish. These patterns are consistent with the hypothesis that sediment affects larval stream amphibians by increasing vulnerability to predation.

DISCIPLINE: Amphibians    STUDY: Alsea, Hinkle Creek, Trask    TYPE: Theses    TAGS: timber harvest, stream amphibians, Pacific giant salamanders, mark-recapture analysis, predation, Larva
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