Phenological mismatches mitigate the ecological impact of a biological invader on amphibian communities

Invasive alien species (IAS) contribute to global biodiversity loss. Given the challenges in obtaining empirical quantitative data on their ecological impacts, the intricate interspecific mechanisms leading to species-specific vulnerabilities remain poorly understood. Here, we tested the hypothesis that temporal mismatches in breeding phenology between native and invasive alien species can mitigate the ecological impacts associated with a biological invasion. Focussing on the invasive American bullfrog (Lithobates catesbeianus), we examined whether its presence was negatively related to that of native amphibian species with regard to their phenological mismatches. We combined an environmental DNA metabarcoding survey in Belgium with a global meta-analysis, and integrated citizen-science data on breeding phenology. Whereas native amphibian communities co-occurring with bullfrog breeding populations were less species rich, native amphibian species displaying substantial phenological mismatches with invasive bullfrogs remained unaffected. We therefore advocate integrating the temporal alignment of native and invasive alien species' phenologies in invasion impact frameworks.