Topsoil translocation as a restoration tool for endangered seasonal killifish in temporary wetlands

Abstract Introduction Wetland loss and fragmentation have placed many species at risk of extinction, highlighting the urgent need for restoration strategies that secure their persistence. Topsoil translocation is a proven technique in plant and invertebrate restoration but has never been tested for seasonal killifishes, which persist through desiccation‐resistant eggs forming sedimentary “egg banks.” Objectives We conducted a 2‐year in situ experiment in southern Brazil to evaluate whether sediment translocation from a natural wetland could establish populations of three seasonal killifish species of conservation concern ( Cynopoecilus nigrovittatus , Garcialebias adloffi , and Megalebias wolterstorffi ) in a newly created wetland. Methods Sediment was relocated from a natural wetland scheduled for drainage, and fish communities were sampled seasonally across two hydroperiods to assess hatching, abundance, and reproduction. Results All three species hatched in the first wet season, and a greater number of individuals was recorded in the second wet period suggesting successful completion of the full life cycle. Cynopoecilus nigrovittatus dominated both years, consistent with patterns in natural wetlands. In contrast, M. wolterstorffi remained rare, while G. adloffi showed reduced late‐season detectability, likely due to microhabitat preferences. Overall abundance increased by 172% from the first to the second cycle, demonstrating habitat suitability and reproductive success in the created wetland. Conclusions Our findings provide the first empirical evidence that topsoil translocation can be used as a restoration tool for seasonal killifishes, effectively relocating viable egg banks and establishing self‐replenishing populations.