Aquatic vegetation limits the impact of Xenopus laevis on macroinvertebrate diversity: implications for pond management

Abstract Invasive predators generate strong negative pressure on local ecosystems. However, the difficulty to control many of them often delays or prevents actions. This conservation challenge requires to identify sustainable long-term solutions to manage invaded ecosystems. Habitat complexity is expected to provide refuges to prey populations and stabilise prey-predator interactions. However, this general prediction is not always supported as some predators benefit from habitat complexity or are insensitive to it, while non-consumptive effects of predation may be detrimental to prey populations. Further, there is still limited evidence that habitat complexity protects prey communities from a non-native invasive predator in real ecosystems. In western France, we investigated the potential protection role of vegetation in the invasive range of Xenopus laevis, a major invasive amphibian worldwide, introduced about 40 years ago. We surveyed 43 colonized ponds in the range core and surveyed ponds characteristics, aquatic and riparian vegetation, macroinvertebrates and X. laevis presence, abundance, and size. We found that habitat complexity in ponds positively influenced the diversity of macroinvertebrates, while it did not affect X. laevis . Our results support the mitigating role of habitat complexity on the impact of an alien predator in a freshwater ecosystem in the longest colonised areas. They also highlight the interest of considering nature-based solutions to promote the long-term coexistence of local communities and the invasive predator through targeted restoration measures.