Handleyomys chapmani, a rodent closely tied to the cloud forests of eastern Mexico, is categorized as “vulnerable” by the International Union for Conservation of Nature (IUCN), particularly due to habitat loss from logging and wood harvesting. The current IUCN range map is spatially inaccurate, is only binary, and does not account for forest cover or climate change. Ecological niche models (ENMs) are used to predict habitat suitability and changes in species’ geographic ranges. By anticipating the possible effects of climate change, ENMs can improve conservation assessments. We improve the current range map of H. chapmani and estimate a future map taking climate change and deforestation into consideration. We obtained occurrence data, collated by collaborators, for H. chapmani, and with four temperature- and precipitation-based bioclimatic variables from the CHELSA dataset, we generated habitat suitability and distributional predictions for current conditions using the algorithm Maxent through the software Wallace. Areas lacking sufficient forest cover (below 70%) were removed from the prediction to account for deforestation. We then forecasted a prediction for the year 2080 using the CCSM4 global circulation model in a high emissions climate change scenario (RCP8.5) to assess the likely upper-bound of severity.
Results/Conclusions
The occurrence data we obtained are more comprehensive and present a wider geographic distribution than previously reported for this species, resulting in a more accurate range prediction. Geographic estimates for the present indicate high suitability along the Sierra Madre Oriental (SMOr) and into the northern Sierra Madre del Sur. Areas of highest suitability are restricted along the ridge of the SMOr. The future projection shows a decrease spatially and in strength of suitability. It also shows no suitability outside of the current range, indicating a shrinking rather than a shifting distribution. Produced via a data-driven operational procedure, this model improves upon the current binary IUCN map greatly by providing much finer resolution as well as a gradient of suitability. These maps are useful for conservation assessment by pinpointing focal regions of high suitability within the range. Future projections of suitability may guide forest protection assessments and planning. Future extensions to this study include use of different climate change scenarios and calculating area of occupancy and extent of occupancy to quantify the trend in the change of the species’ estimated distribution for use in a revised IUCN threat classification for the species.