The Herpetological Journal

pp.167-173

Authors: I. Martínez-solano, L. J. Barbadillo And M. Lapeña

Abstract: We examined the effect of fish stocking practices on the populations of seven amphibian species in a montane area in the Sierra de Neila (north-central Spain). We compared values for amphibian species richness and amphibian densities between ponds where fish have been introduced and ponds where fish are absent. Our results show that ( 1) amphibian species richness was significantly lower in ponds where fish have been introduced; (2) we found contrasting patterns of pond occupancy by the different amphibian species: on the one hand, two out of seven species (Bufo bufo and Rana perezi) coexist with fish, whereas the other five species breed exclusively in ponds where fish are absent; (3) based on comparisons of presence/ absence data for species present in the area in 1981, 1991 and 2001, we concluded that two amphibian species have suffered severe declines in the last decades. Presently, Alytes obstetricans is almost exclusively confined to a few fish less streams, whereas Salamandra salamandra appears to have been completely extirpated from the whole. area. This local decline of S. salamandra seems to be general for the whole region of the Sistema Iberico (North-central Spain). The possible role of fish stocking practices in these declines is discussed.

Keywords: amphibian decline, conservation, exotic fish, Spain