Role of flood-control basins as summer habitat for wetland species - A multiple-taxon approach

In the era of global climate change, the risk of large-scale flood disasters has been increasing. Green infrastructure has gained increasing attention as one of the strategies for adaptation to mega-floods because it can concurrently enhance regional biodiversity and ecosystem services. Previous studies have assessed the efficacy of flood-control infrastructure in protecting biodiversity in urban areas. However, whether such infrastructure enhances biodiversity in other environments remains largely unknown. In this study, we assessed the function of flood-control basins constructed for flood risk management as summer habitat for wetland species in agricultural landscapes. We compared the species assemblages of four different taxa (fishes, aquatic insects, birds, and plants) among four water body types (flood-control basins, channelized watercourses, drainage pumping stations, and remnant ponds). We found that the flood-control basins had comparable or higher species richness and abundance of most taxa than the other water body types. We also found that the species compositions in the flood-control basins were characterized by pioneer species, which prefer shallow water or can adapt to fluctuations in water levels (e.g., herbivorous insects, shorebirds, and hygrophytes). These findings suggest that flood-control basins can provide summer habitat for wetland species, especially for species that inhabit environments with hydrological variation, and utilizing flood-control basins as green infrastructure is a reasonable option for conserving regional biodiversity in agricultural landscapes.