Biodiversity in an Isolated Suburban Reservation: Amphibians in the Middlesex Fells

Amphibians are indicators of local ecosystem health - they are weak dispersers in comparison to other vertebrates, have sensitive permeable skins, and typically exhibit a biphasic lifestyle, utilizing both aquatic and terrestrial habitats during different lifestages. By cataloging the amphibian species inhabiting different parts of the Middlesex Fells Reservation, this research is intended to provide one measure of the reservation\u27s ecological health and to examine patterns of amphibian species richness at two spatial scales (in the landscape and at aquatic breeding habitats) that are relevant to amphibian ecology. The Fells is a mixed-use natural recreational area within a thirty minute drive of millions of Boston area residents. Reservoirs and roads separate sections of the Fells from one another and provide an opportunity to comparison test how these sections serve as refuges preserving amphibian species diversity. The study area consists of six forested sections that vary in size, shape and number of: pools, ponds and streams. Area of the six sections studied is the single best predictor of amphibian species richness in a section. In addition, landscape analysis indicates that amphibian richness is high in sections with numerous pools, and with a low average distance between pools. In the habitat-level analysis, linear regression showed that pool area and pool hydroperiod are strong predictors of amphibian species richness. A multiple stepwise regression model including both landscape and habitat variables was the best explainer of amphibian richness at vernal pools. During two years of field research (2007-2008), I found evidence of breeding for nine amphibian species. Species-specific analyses have shown some marked differences in habitat preferences among amphibian species. Wood frogs and American toads were tolerent of the smallest and most ephemeral breeding pools in the study, whereas spring peepers and spotted salamanders required larger, late-drying breeding pools. This research will begin a baseline record of amphibian species in the Fells. It is my intent that the patterns of species richness observed at the landscape and habitat level, as well as the habitat requirements I have documented, will assist agencies that wish to preserve amphibian species diversity by making ecologically sound management decisions