Rare Now and Rarer in the Future? Future Potential Distributions of the Endemic <scp> <i>Lampetra zanandreai</i> </scp> Showed Contractions in Its Suitable Areas

ABSTRACT The Mediterranean basin is a hotspot of freshwater endemisms and restricted‐range species, which are among the most threatened worldwide. The Adriatic brook lamprey Lampetra zanandreai is a non‐parasitic, freshwater‐resident lamprey whose core distribution lies in the Po River basin (Northern Italy). This species is highly sensitive to anthropogenic pressures: it has historically been threatened by river alterations, and climate change is now emerging as an additional threat. In this study, we compiled and updated the distribution of L. zanandreai and applied species distribution models to project its current and future potential distribution under different climate models for 2050. We further performed a river network‐level analysis to assess the relevance of human stressors and the effectiveness of the EU Natura 2000 network in representing highly suitable areas. Our outcomes indicate a substantial range contraction coupled with an upward altitudinal shift. Areas of overlap between the current and future suitable areas highlight potential climatic and environmental refuges, although limited and fragmented. Highly suitable riverine cells largely overlap with cells under a higher human footprint, showing how the species is caught between multiple pressures that exacerbate its vulnerability. In addition, protected areas perform poorly in covering both current occurrences and predicted suitable habitats. These findings provide crucial insights to support conservation planning, suggesting potential areas for the protection, management and monitoring of this threatened species. The long‐term persistence of L. zanandreai requires urgent mitigation of human pressures, particularly through the restoration of river connectivity to facilitate population exchange and access to future refuges.