Biological invasions in the Anthropocene: Patterns, processes and hidden invasions in an alien amphibian model

Comparative genetic analyses across E. johnstonei, its successful alien congener E. antillensis, and the island endemic E. portoricensis show consistently low genetic diversity in both native and exotic populations, indicating that genetic impoverishment does not preclude invasion success. Instead, species distribution models highlight human footprint as a key predictor of the frog’s wide exotic range. Furthermore, microbiome analyses reveal distinct microbial communities between native and introduced populations, suggesting that microbial restructuring accompanies range expansion and may reflect underlying adaptive or transfer processes.Together, these findings challenge conventional invasion theory by illustrating that islands can act as sources instead of sinks and that species with low genetic diversity can thrive across continents when human-mediated disturbances create favorable conditions.

The study argues that conservation strategies should prioritize protecting native habitats over targeting adaptable alien species that succeed largely because of anthropogenic change. More broadly, it calls for a rethinking of "nativeness" in an era of rapid environmental transformation and underscores that the resilience of both macro- and micro-communities - rather than species origin - will shape biodiversity outcomes in the Anthropocene.