Mapping a super-invader in a biodiversity hotspot, an eDNA-based success story

The lesser Antilles archipelago in the Caribbean is known as a biodiversity hotspot, hosting many endemic species. However, recent introduction of highly invasive species, Australian redclaw crayfish (Cherax quadricarinatus), has led to significant threats this fragile ecosystem. Here we developed, validated, and optimized species-specific eDNA-based detection protocol targeting 16S region mitochondrial gene C. quadricarinatus. Our aim was assess distribution across Martinique Island. developed assay showed high sensitivity laboratory, mesocosm field conditions. A positive correlation found between species biomass, probability efficiency through experiments. Moreover, eDNA persisted up 23 days tropical freshwaters. We investigated total 83 locations, spread over 53 rivers two closed water basins using our novel traditional trapping, latter, undertaken confirm reliability molecular-based method. Overall, detected quadricarinatus at 47 locations 28 all trapping sites were for eDNA. that monitoring less time-consuming influenced by crayfishes often patchy distributions, proving more reliable tool future large-scale surveys. clear threat worrying particularly alarming belongs one 25 identified hotspots on Earth.