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Abiotic factors influencing abundance and microhabitat use of stream salamanders in southern Appalachian forests

Crawford, John A., Semlitsch, Raymond D.
Forest ecology and management 2008 v.255 no.5-6 pp. 1841-1847
salamanders and newts, Caudata, microhabitats, habitat preferences, soil water, canopy, soil temperature, environmental factors, streams, riparian forests, statistical models, regression analysis, habitat conservation, plant litter, Appalachian region, North Carolina
In order to evaluate the effects of habitat loss and degradation on amphibian populations it is necessary to determine species-specific habitat use and how this influences abundance. While a number of studies have examined the influence of competition and predation in stream salamander assemblages in the southern Appalachian Mountains, there remains a relative lack of knowledge on the microhabitat use of these species. Using area-constrained daytime searches, we investigated microhabitat use and abundance for stream-breeding salamanders in mature forests in southern Appalachian streams from May to August 2004. We found that leaf litter depth, soil moisture, and canopy cover were all higher and soil temperature was lower in plots where stream salamanders were encountered compared to plots where salamanders were not encountered. A regression analysis using the information-theoretic approach (AIC) revealed that the model that included distance from stream, leaf litter depth, soil moisture, and soil temperature had the strongest support for predicting stream salamander abundance at the landscape level (ω i =0.99). Microhabitat use in many species of stream salamanders is mediated by a number of complex factors including environmental variables, competition, and predation. Alteration of habitats likely results in increased competition and predation rates and subsequent local population declines, so it is imperative to mitigate the effects of practices such as even-aged timber harvesting in order to conserve amphibian biodiversity.