Hotspots of tree richness and carbon storage in existing and potential protected areas in Mexico

Understanding the spatial relationship between biodiversity and carbon storage is essential for guiding conservation efforts to tackle jointly the biodiversity loss and climate change crises. Here, we assess tree richness and carbon storage patterns, their spatial congruence within and outside protected areas and to what extent existing protected areas safeguard tree diversity‐carbon storage hotspots. We used tree species richness and above‐ground carbon storage data derived from 234 national forest inventory plots to fit machine learning models using a set of climatic, topographic and edaphic predictors in northwestern Mexico. We then assessed the uncertainty and spatial congruence of predicted tree richness and carbon storage. Areas with high minimum temperature and evapotranspiration contain greater tree richness and carbon storage. These results suggest that changes in temperature and precipitation regimes have the potential to alter both plant diversity and carbon pools. Hotspots, where the top quintile values of tree richness and carbon storage overlap, occupy 10.2% of the study region; however, most lie beyond existing protected areas, which currently safeguard less than 0.2% of these hotspots. Synthesis and applications : We identified areas of potentially high conservation value, including prospective ecological reserves and corridors. We recommend policy makers and land managers to protect these hotspots of tree richness and carbon storage and establish connections with existing reserves to facilitate species movement and range expansion under changing climatic conditions. Biodiversity and carbon pools should be considered together for more effective spatial planning processes, especially at the regional scale, where management decisions can be more easily implemented and evaluated.