The response of amphibian communities to fish and habitat features in Mediterranean permanent ponds

Generalized linear models were used to test the effect of fish, using ponds with and without fish and habitat features as covariates, on richness and abundance of amphibian species. Five fish species and six amphibian species were recorded in 60 permanent ponds located in central Italy. The choice of covariates (macrophyte cover and pond surface area) was made after studying the correlations. The richness of amphibian species was not significantly affected by fish presence or macrophyte cover, in line with previous studies, since almost all the fish species were non-predatory. However, abundance of urodeles (newts) was negatively affected by fish and positively affected by macrophyte cover. Although fish may strongly influence the abundance and composition of amphibian communities, the results indicate that the cover of aquatic macrophytes may increase the available habitat for amphibians and therefore their abundance. Anuran species preferred ponds where fish were present, since both groups preferred larger ponds. Concordance between fish and amphibian species composition was not found by the Mantel and Partial Mantel tests. This indicates that the fish assemblages do not predict which amphibian species occur in the pond.