Getting the ‘most out of the hotspot’ for practical conservation of groundwater biodiversity

Conservation planning aimed at halting biodiversity loss has seldom focused on groundwater environments due to the lack of suitable management tools and data. Using harpacticoid crustaceans as a test case, we explore the potential of implementing an approach based on Conservation-Relevant Hotspots for practical conservation of groundwater biodiversity. Conservation-Relevant Hotspots are identified by intersecting species richness, endemicity, and taxonomic distinctness with the aim to minimize the total area to protect. We show that, by targeting five Conservation-Relevant Hotspots that cover only 1.9% of the European land surface, one would protect as much as 44% of the harpacticoid crustacean richness, 93% of its endemicity, and 98% of its taxonomic distinctness. About 28% of the area occupied by these hotspots overlaps with protected areas, which calls for an increase in their protection coverage. Our framework proved a useful tool for conservation planning of environments where spatial or socio-economic constraints occur.