Relationships among Amphibian Assemblage Structure, Wetland pH, and Forest Cover

A common mesofilter approach to conservation of biological diversity and ecosystem function used in agricultural and urban landscapes is maintenance of wetlands and an undisturbed terrestrial buffer surrounding wetlands. Although it is generally accepted that forest buffers protect wetland-associated biological diversity and ecosystem function, the effectiveness and optimal spatial extent of buffers is still an area of debate. During 2007 and 2008 we surveyed amphibians and environmental conditions associated with 54 depression wetlands on the Delmarva Peninsula of Maryland, USA, to examine the role of forest buffers and wetland characteristics in structuring amphibian communities. Forest cover within a 50-m buffer surrounding wetlands was correlated (r=−0.81) with wetland pH but no other wetland characteristics. Wetland pH, canopy cover, hydroperiod, and adjacent forest cover were important predictors of wetland use by individual amphibian species, with many species more likely to occur at wetlands that dried late in the hydrological year and with open canopies. At least one common species preferred circumneutral pH and several restricted-distribution species preferred lower pH (