Assessing climate change impacts on the geographical distribution of Cupressus sempervirens in the Mediterranean region.

Cupressus sempervirens L., a long-lived conifer of the Cupressaceae family, plays a vital ecological, medicinal, and economic role in the Mediterranean basin. Due to the species' sensitivity to climatic fluctuations, particularly temperature and precipitation regimes, understanding its potential distributional shifts under climate change is critical. This study employs ecological niche modeling to quantify the current and future potential geographic distribution of C. sempervirens under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5) for the mid-twenty-first century (2041-2060). Model outputs identified mean diurnal range (bio2), precipitation seasonality (bio15), and annual precipitation (bio12) as key determinants of habitat suitability. Presently, suitable habitats are concentrated throughout the Mediterranean region, with moderate suitability extending into the Euro-Siberian and Irano-Turanian domains. Future climate projections indicated an expansion of climatically suitable areas, most consistently within the Mediterranean basin, where predictions showed higher reliability, whereas additional gains in northern regions (e.g., around the Caspian and Black seas) were associated with greater model uncertainty, reflecting overall increases in suitable habitat of 14.7% under SSP2-4.5 and 16.4% under SSP5-8.5. These findings provide critical insights for developing effective monitoring frameworks and conservation strategies to enhance the resilience and adaptive capacity of C. sempervirens populations amid ongoing climate change.