Quarry ponds are hotspots of amphibian species richness

Amphibians are among the most severely declining taxonomic group worldwide. Recent studies have shown that quarries may have a high conservation value for biodiversity conservation. However, well-replicated research on the importance of quarry ponds for amphibian assemblages has been scarce thus far. The aim of this study was to compare the environmental conditions and composition of amphibian assemblages of 15 randomly selected quarry ponds with those of 15 control ponds in the surrounding landscape. For each pond, we assessed several parameters of habitat and landscape quality. The effects of environmental conditions on overall species richness and number of threatened species were analysed using Generalized Linear Mixed-effects Models. Our study revealed strong differences in habitat quality and composition of amphibian assemblages between quarry and control ponds. In particular, a larger area of the semi-aquatic zone, a longer sunshine duration and the absence of fish were typical of quarry ponds, whereas a taller vegetation at the shoreline characterized control ponds. As a result, overall species richness and number of threatened species were higher in quarry ponds compared with control ponds. Overall, quarry ponds had a higher habitat quality than control ponds. In particular, (i) the large area of sunlit and warm microhabitats and (ii) the absence of fish predators favoured species richness of amphibians at the quarry ponds. Consequently, quarry ponds -thanks to their early-successional stages-have a high conservation value for amphibians.