Open access big data are crucial to investigate the spatial arrangement of biodiversity facets, its drivers, and the existing and potential threats to the persistence and functionality of ecosystems.

Groundwater-dependent ecosystems (GDEs), including purely subterranean aquatic environments as well as groundwater-fed springs and the hyporheic zone, host diversified metazoan communities, where crustaceans usually represent the most species-rich and abundant group. Groundwater-dwelling crustaceans play pivotal functions in GDEs, such as nutrient recycling and bioturbation. Furthermore, they often show restricted distributions and high sensitivity to environmental variations, making them particularly vulnerable.

Despite the ubiquity of crustaceans in GDEs, open access datasets about these organisms have been poorly available until very recently. In 2024, we compiled EGCop, the first expert-validated, open access dataset encompassing all the known species of European obligate groundwater-dwelling copepods (Crustacea: Copepoda), which represent a preponderant portion of the metazoan diversity and biomass in groundwaters. Taking advantage of EGCop and spatially explicit environmental predictors at European scale, we implemented various GIS and ecological modelling techniques to highlight candidate priority areas for conserving European GDEs and their crustacean diversity.

We found that groundwater copepods’ diversity is not comprehensively represented within the existing network of European protected areas. In this context, the species richness hotspots and the endemicity areas that our analyses delineate in distinct European karst regions are strong candidates to deliver conservation actions. We also found that different copepod species show distinct responses to environmental variability at local-to-regional scale and have potential distributions extending far beyond their known ranges, suggesting the need for additional sampling campaigns across less explored European regions to fill existing knowledge gaps.

As these patterns are likely shared with other groundwater-dwelling crustacean groups, the obtained results are being complemented with additional analyses to expand their taxonomic scope, thus providing more comprehensive conservation-relevant information.