Stormwater ponds ("SWPs") are artificial roadside structures, conceived to retain and clean polluted runoff water, before its release to the environment. SWPs were not designed as suitable habitats for wildlife. However, SWPs in Europe are frequently used as breeding sites by amphibians, especially by the European green frog (Pelophylax sp.). Yet, the potential longterm effects of pollutants within SWPs on the populations of this species are unknown. In this study, we investigated the suitability of SWPs as a habitat for European green frogs living in Alsace, NE France, a region with a highly modified landscape that mainly consists of croplands with few natural wetlands remaining. We compared various biological indicators of individual health in 709 green frogs belonging to different life history stages, living in 9 semi-natural ponds (SNPs) and in 25 SWPs. There were no differences between these two pond types for most of the indicators investigated. However, juveniles had a lower body condition (-124%) in SWPs, while adults were 8.3% larger and 41.4% heavier in SWPs. Based on these results, we suggest that SWPs are not a suitable habitat for the development of European green frogs (i.e. juveniles), but may serve as a substitute habitat for adults in a highly modified landscape with few natural wetlands remaining. SWPs may especially act as relay sites, allowing frogs to colonize relict wetlands.

To mitigate habitat fragmentation and roadkill, roads are increasingly equipped with wildlife fences and underpasses. However, the effectiveness of such fences in preventing road access for amphibians has not been tested under controlled conditions. In 2019 and 2020, we tested the efficacy of full panel fences of differing material, height, and shape (presence/absence of an overhang), to prevent road access for adult and juvenile amphibians. We selected five species according to locomotion mode: Natterjack toads (runners), European green toads (short-distance jumpers), agile frogs (proficient jumpers), American tree frogs (proficient climbers) and smooth newts (climbers). We found that Natterjack and green toads were unable to cross a concrete fence with a height of 13 and 24 cm, respectively. Addition of a 10 cm overhang reduced the height required to prevent crossing further to 10 and 17 cm, respectively. The ability of these less agile species to cross a certain fence height depended on body length. By contrast, jumping agile frogs and climbing tree frogs were not stopped by the greatest fence height tested (40 cm). However, addition of the overhang stopped the climbing tree frogs at a concrete fence height of 35 cm. An alternative metal fence (with overhang) was tested with some species and performed similar to the concrete fence (with overhang). Finally, the greatest concrete fence height passed by climbing juveniles was 20 cm (smooth newts). Hence, to stop amphibians from road crossing, we recommend the construction of durable (concrete or galvanized metal) and well-maintained fences with a minimum height of 40 cm with a 10 cm overhang.

No abstract

In the original publication the author names were presented as family name and given name. The correct author names are presented in this Erratum.