Stormwater basins of the New Jersey coastal plain: Subsidies or sinks for frogs and toads?

Stormwater basins are commonly employed structures designed to mitigate the negative effects of urban runoff. They are ubiquitous in the urbanized landscape; yet the effect of these basins on anurans has only recently been addressed. Stormwater basins have the potential to influence the breeding distribution of anurans by being sources for some species and sinks for others. Our study aims to determine which species benefit from the existence of stormwater basins, which species are negatively impacted, and what variables are the best predictors of these effects. We monitored thirty-six permanently-ponded basins in southern New Jersey for the presence of anuran larvae and calling males by aural surveys, dip-netting and trapping. We assessed fish presence by interviews, visual encounters, dip-netting, and traps. We divided near shore buffer areas into impervious surface and managed or unmanaged categories for both grass and woody vegetation. Two connectivity metrics, distance to canopied corridor and percent of undeveloped upland were analyzed with ArcGIS. Fish were detected in 92% of the basins. Resistance to fish predation distinguished successful species, those with larvae present, from unsuccessful species, those with calling activity but no larval presence. Connectivity to and availability of terrestrial habitat were significant predictors of the breeding species richness at the basins. Number of calling species increased as access to and amount of terrestrial habitat increased. Therefore, design, management, and placement of permanently-ponded basins can impact anuran communities. Additionally, as wet basins are sources for Rana catesbeiana, where bullfrogs are invasive, basins will likely increase propagule pressure.