Different Anuran Species Show Different Relationships to Agricultural Intensity

Studies on associations between agricultural intensity and anurans have found inconsistent results among species. However, studies vary in their definitions of agricultural intensity and spatial scales of analyses. If differences are real, they might be caused by differences among species’ adult or juvenile habitat associations with agricultural intensity, and/or differences in sensitivities to agricultural inputs, e.g., fertilizers. We estimated relative abundances of eight anuran species in 39 ponds located in landscapes of varying agricultural intensity. We measured row crop and cereal grain cover, our measure of agricultural intensity, at multiple spatial extents. We then constructed path models for individual species to determine direction and potential causes of associations with agricultural intensity, measured at the scale of effect of each species. We found highly variable associations with agricultural intensity among anurans. As predicted, much of this variation could be explained by adult habitat amount and larval habitat quality. Overall, our results suggest that agricultural intensity, at least at levels found in eastern Ontario, can affect anurans through multiple pathways and mechanisms, in both positive and negative directions. We therefore suggest that authors use caution if making general statements about the impacts of agricultural intensity on anurans