Spontaneous succession on spoil banks supports amphibian diversity and abundance

• Conservation potential of spoil banks as habitat for amphibians was confirmed.
• Amphibian presence, species richness and abundance were higher without reclamation.
• Nine of 12 amphibian species in the region are able to colonize post-mining sites.
• Numerous and various water habitats are key to amphibian diversity and abundance.

The ecological value and conservation potential of post-mining areas have been increasingly recognized by scientists and conservationists during recent decades. Especially valuable are sites left to spontaneous succession, which constitute habitats with high species diversity, or habitats that serve as refuges for threatened species. In contrast to several other taxa, there is a lack of such evidence for amphibians, despite the assumption that primary succession leads to a more suitable environment for amphibians than does technical reclamation. Therefore, we compared the effects of technical reclamation and spontaneous succession on amphibian presence, species richness, and abundance of the model species Rana dalmatina in technically reclaimed and unreclaimed sections of spoil banks in the Czech Republic's North Bohemian brown coal basin. We found that most recorded amphibian species, and R. dalmatina in particular, occurred predominantly within successional spoil bank sections. Apart from reclamation status, amphibians preferred partially vegetated ponds (5–75% vegetation cover) having gently sloping shores (<30°) and lower water conductivity. Mean species richness per pond (1.95 vs. 1.20), the proportion of ponds occupied by amphibians (88.5% vs. 69.4%), and the mean numbers of R. dalmatina clutches per pond (9.05 vs. 1.65) were significantly higher at unreclaimed sites compared to technically reclaimed sites. This study confirms the conservation value of post-mining sites for amphibians and evidences that sites left to spontaneous succession provide more suitable habitats for amphibians compared to technically reclaimed sites. Key habitat characteristics driving amphibian assemblages within post-mining sites are identified and guidelines for effective protection of amphibians in post-mining areas are proposed.