Amphibian Community Richness in Cropland and Grassland Playas in the Southern High Plains, USA

Abstract

Land use mediated habitat changes are associated with global amphibian declines. Intensive farming occurs in the Southern High Plains, USA, causing habitat loss through cultivation and subsequent sedimentation of playa wetlands. We determined the effects of sedimentation and other factors (e.g., hydroperiod, vegetative cover, wetland volume loss due to sediment, and playa density) hypothesized to have an influence on amphibian species richness. We sampled amphibian species richness in 40 playas with cropland watersheds and 40 playas with native grassland watersheds. Hydroperiod was the primary factor influencing amphibian species richness; playas with longer hydroperiods had higher cumulative amphibian species richness than playas with shorter hydroperiods. Percent vegetative cover was also positively related to species richness. Sedimentation of playas in the Southern High Plains reduces hydroperiod length and the number of playas available to breeding amphibians, two factors influencing richness. Shortened hydroperiods negatively affect reproductive success of amphibian species with long larval periods [e.g., barred tiger salamander (Ambystoma tigrinum mavortium), American bullfrog (Rana catesbeiana)], limiting amphibian species richness. Efforts to conserve amphibian species richness in playas should focus on reducing sediment and ensuring availability of sufficient vegetative cover.