Freshwater biodiversity is not adequately addressed by the current protected areas of the Caribbean biodiversity hotspot

Abstract

AimFreshwater species face significant challenges from direct and indirect anthropogenic impacts, leading to a global decline in freshwater biodiversity. Protected areas are a key tool for conservation, but their effectiveness in covering freshwater biodiversity remains uncertain. This study assesses the protection coverage of freshwater macroinvertebrates, vertebrates, and macrophytes in Cuba against the 30% conservation targets set by the Convention on Biological Diversity. LocationCuban biodiversity hotspot, including freshwater ecosystems across the Cuban archipelago. MethodsWe compiled occurrence data for 304 freshwater macroinvertebrates, 31 fish, and 24 macrophyte species across the Cuban archipelago and modelled species distributions at the sub-catchment scale using Random Forest and Maxent. Models were fitted for species with at least 10 occurrence records, and the resulting estimates were combined into conservative ensemble suitability estimates. We then performed spatial conservation prioritization using habitat suitability as feature amounts. For species for which model fitting was not feasible, feature amounts were derived by treating sub-catchments with occurrence records as suitable. Spatial conservation prioritization was conducted under a 30% conservation target for each species and two prioritization designs: (i) lock-in, in which planning units overlapping the Cuban National System of Protected Areas (SNAP) were forced into the solution, and (ii) free-choice, in which all planning units were available for selection. We compared these prioritization solutions with SNAP in terms of achieving 30% coverage of suitable habitat for each species and their contribution to hydrological connectivity. ResultsSNAP left major freshwater representation gaps across Cuba, with the strongest shortfalls in Decapoda, Hemiptera, Coleoptera, and Ephemeroptera, whereas Odonata and vertebrates were comparatively better represented. Endemic species were also poorly covered, and many were entirely absent from SNAP. Spatial prioritization solutions showed that the 30% target was achievable for all species, but only through substantial expansion or redesign of the current network. The lock-in solution required a larger and more costly network but achieved higher median species coverage, whereas the free-choice solution met the same target more efficiently with less area and lower cost. Both prioritization scenarios also improved hydrological network structure relative to SNAP, producing larger connected freshwater clusters and identifying connector units that linked previously disconnected protected areas. Patterns of planning-unit importance differed among taxonomic groups, indicating that priority areas for one group do not necessarily capture the conservation needs of others. Main conclusionsOverall, our results show that the current protected areas of the Caribbean biodiversity hotspot do not adequately address freshwater biodiversity. SNAP leaves major representation gaps, with 217 of 359 species failing to meet the 30% target, particularly among invertebrates and endemic species, and provides neither an efficient nor well-connected basis for meeting ambitious freshwater conservation goals. The strong taxonomic variation in both protection gaps and planning-unit importance indicates that priority areas for one group do not necessarily represent freshwater biodiversity as a whole, underscoring the need for explicitly multi-taxon planning. Nevertheless, substantial improvement is possible: expanding around the current network would enhance representation and connectivity, although requiring an approximately 70% increase in area, whereas a less constrained redesign could meet the same targets more efficiently. The most effective long-term strategy may therefore be to retain and strengthen the parts of SNAP that already contribute to freshwater conservation, while strategically expanding and reconfiguring the network based on freshwater-specific priorities.