Contrasting Climatic and Land-Use Scenarios Reveal Divergent Futures for the Mexican Narrow-Mouthed Toad, Amphibia, Microhylidae Hypopachus variolosus (Cope, 1866)

Abstract

We assessed the current and possible future predicted distributions of the Mexican narrow-mouthed toad, Amphibia, Microhylidae Hypopachus variolosus (Cope, 1866) across its range to evaluate vulnerability under global change. (2) Methods: We integrated 481 validated occurrence records across the species' distribution range, including 120 records from Mexico, with bioclimatic and land-cover predictors to build ensemble ecological niche models. We additionally incorporated human footprint metrics to evaluate anthropogenic pressure and projected future habitat suitability under climate and land-use change scenarios. (3) Results: Models showed high performance (TSS > 0.80; AUC > 0.90), identifying temperature and precipitation extremes as main drivers. Suitable habitats extended across both coasts and revealed novel areas in central Mexico. The most suitable habitat occurred under low human pressure, although localized impacts were detected. Deforestation in the Yucat \& aacute;n Peninsula reduced tree cover despite high climatic suitability. Future projections for 2050 under RCP 8.5 indicated marked reductions in modeled high-suitability areas, particularly in central Mexico. (4) Conclusions: These findings indicate high vulnerability to climate and land-use change and support updating distribution limits, incorporating new regions into conservation planning, and reassessing threat status to promote long-term persistence.