UBC Theses and Dissertations
The status and distribution of terrestrial amphibians in old-growth forests and managed stands Dupuis, Linda A.
In this thesis, I compare the abundance of terrestrial amphibians in old-growth forests and young and mature post-harvest stands. I also examine the habitat features with which they are strongly associated, and contrast these between old growth and second growth to gain insight on the specific effects of logging operations. Terrestrial amphibian surveys were carried out by means of two techniques: 1) area-constrained searches (ACS), and 2)log surveys (LGS). ACS consisted of thoroughly searching a series of quadrats (3x3m in1991, 1x2 m in 1992), which were randomly placed within study sites. LGS involve detailed searches of logs in early, intermediate and advanced stages of decay. My study demonstrated that clearcut harvesting reduces terrestrial amphibian populations by as much as 70%. I suggest that the mechanism behind this pattern is a reduction in the availability of moist microhabitats. In support of this, salamander densities in managed stands were similar to those in old growth within 10 m. of streams. Moreover, managed stands lack large logs in intermediate and late stages of decomposition, and these are an important source of cover for salamanders, notably the western red-backed salamander, a. vehiculum. The proximity of old growth to managed stands may also be crucial. Second growth habitats which were isolated from old growth, maintained lower densities of terrestrial amphibians than second-growth stands adjacent to old growth. In light of my results, I make several recommendations to forest managers, which consider the needs of terrestrial amphibians.
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