Creating more diverse ponds: a boost for aquatic biodiversity in pondscapes

Abstract Following habitat destruction through the intensification of agriculture and urbanisation, about 50–90% of European ponds disappeared over the course of the twentieth century. As their importance for freshwater biodiversity is now increasingly recognised, more ponds are being created, but their effects on pondscape and regional biodiversity are too rarely monitored. This study investigates the benefits to aquatic species diversity of building more ponds near Geneva, Switzerland. The communities of aquatic macroinvertebrates and macrophytes of pre-existing ponds were compared with that of additional ponds created specifically to provide more habitats for biodiversity. The creation of additional ponds increased macroinvertebrate and macrophyte richness at the level of individual pondscapes as well as at the larger regional scale. It also significantly improved beta diversity within pondscapes, leading to richer, more heterogeneous pond communities. Some additional ponds were intentionally designed quite differently from the previous ponds, allowing for a variety of sizes and shallower depths, which benefitted vulnerable species typical of temporary pools. This study highlights the significant contribution of pond creation on freshwater biodiversity, even in landscapes already characterised by rich, high-quality ponds, and the importance of maintaining a range of diverse pond types that will benefit various species.