Amphibian Community Responses to Playa Restoration in the Rainwater Basin

Abstract

Alterations to wetland hydrology associated with conversion of grassland watersheds to croplands can alter functional components that drive many wetland ecosystem services. Biodiversity provisioning is one of many services that can be negatively impacted by grassland conversions. Our objective was to compare amphibian communities of playa wetlands in native grassland versus cropland watersheds and to determine if restoration of cropland wetlands via sediment removal improved these habitats for amphibians. We collected amphibian species richness, water depth, wetland area, and emergent plant cover data from 34 playa wetlands in 2008 and 32 playa wetlands in 2009. Playas were selected to include those within natural grassland watersheds (i.e., reference playas), cropland watersheds, and restored watersheds within the Rainwater Basin (RWB) of Nebraska. While we did not detect a difference in amphibian species richness among land-use types in 2008, in 2009 (a dry year within the RWB) amphibian species richness averaged nearly two times greater in restored playas (3.18) compared to cropland playas (1.70). Average water depth (2008 and 2009) and playa area (2008 only) were best predictors of amphibian species richness. Restored playas provided the most reliable water availability for amphibians in the RWB where 90 % of the wetlands have been drained.