Local and landscape influence on richness of amphibian species breeding in seasonal ponds in the Spanish south-Atlantic littoral. Impact determination
The increase in urban land and the continuous increment of road network experienced by littoral zones contribute to the loss, degradation and isolation of both terrestrial and aquatic habitats in which amphibians spend the diﬀerent stages of their life cycle. The aim of this study is to explain the relationship between the characteristics of 17 seasonal ponds located in the Atlantic littoral of Cádiz province (SW Spain), the land uses in their surroundings, the road network, and the diversity of amphibian species. Our results show that amphibian richness is higher in larger ponds with longer hydroperiods, surrounded by forest and scrubland, and away from the nearest road. Roads, and in particular secondary roads, have a great and negative impact on amphibian richness because the shorter the distance between the pond and the road was, the fewer breeding species were found. From the data obtained in this study, we have classiﬁed the ponds according to their status of conservation. This classiﬁcation demonstrates that 94% of the studied ponds require immediate measures to be taken in order to reduce the negative impact of habitat fragmentation caused by roads. Finally, in order to maintain healthy amphibian populations at the long term, forests and scrublands surrounding ponds must be protected, and connectivity among ponds, as well as with the terrestrial habitats in the vicinity, must be ensured. Preventing amphibians from road kills during their migration movements can be achieved by means of constructing underpasses and tunnels in hot spots.