Maintaining biodiversity with a mosaic of wetlands: factors affecting amphibian species richness among small isolated wetlands in central Florida.

The biodiversity value of a wetland is linked not only to its position in the landscape relative to other wetlands, but also to its habitat characteristics. I monitored amphibian species richness among 12 small, isolated, and undisturbed wetlands (which occur on lands permitted for phosphate mining) in central Florida during the 2005 and 2006 breeding seasons. I used seven habitat and landscape variables to characterize the environments of the wetlands and generalized linear models to determine which of these variables had the greatest influence on the occurrence of seven amphibian species (Anaxyrus terrestris, Gastrophryne carolinensis, Hyla gratiosa, Lithobates capito, L. catesbeianus, L. grylio, and Pseudacris nigrita verrucosa). Significant models for each species incorporated six of the seven habitat and landscape variables: distance to permanent water (2 spp.), distance to nearest wetland (3 spp.), vegetation heterogeneity (2 spp.), hydroperiod (2 spp.), presence/absence of fish (1 sp.), and distance to canopy cover (1 sp.). I suggest that source/sink metapopulation and patchy population dynamics in a given year are affected in part by environmental variables of ephemeral wetlands as they affect individual amphibian species. I suggest that a diversity of environmental conditions among wetlands produces the greatest amphibian biodiversity in this system, and that conservation and restoration efforts should emphasize environmental heterogeneity