More amphibians than expected in highway stormwater ponds

Some structures developed for particular technical anthropogenic uses are colonized by biodiversity, but their potential roles have not been seriously considered. Here, we examined whether and how highway stormwater retention ponds are colonized by amphibians and are used as reproduction sites in human-dominated landscapes. We addressed their role as habitats for amphibians by sampling amphibians in highway ponds (n=58) and in surrounding non-highway ponds (n=45) and comparing the species richness and the amphibian abundance using occupancy models that take detectability into account. As expected, highway ponds differed in abiotic conditions from surrounding ponds. Surprisingly, we found seven different amphibian species with breeding populations, including one emblematic rare species (Triturus cristatus), in these artificial ponds. Further, the proportion of the highway ponds where amphibians were detected was about similar to that of surrounding ponds. Note, however, that the amphibian abundances were lower in highway ponds. Surprisingly, our results suggest that highway ponds may contribute in altered landscapes to the biodiversity of the pond network at a regional scale. Because the adoption of biodiversity-friendly management measures for these artificial ponds could promote biodiversity in such landscapes, we highlight the most important factors driving amphibian distribution in these ponds. Due to the importance of these issues, we stress the need for complementary studies to continue to precisely examine the potential roles of these ponds as habitats for amphibians and then to propose, if useful, technical pond design and management recommendations relevant for common biodiversity.