From Ecological Niche to Conservation Planning; Climate-Driven Range Dynamics of Ephedra intermedia in Central Asia

Abstract

Ephedra intermedia, a medicinally significant plant, is an important component of arid and semi-arid ecosystems across Central and South Asia. This research sought to predict the present and future distribution of E. intermedia by applying ecological niche modeling (ENM) methods. The model incorporated comprehensive bioclimatic and edaphic variables to predict the species' habitat suitability. The results demonstrated high predictive accuracy, highlighting the importance of temperature seasonality, annual temperature range, soil pH, and nitrogen content as key species distribution determinants. The current habitat suitability map revealed core areas in Afghanistan, Pakistan, and Tajikistan mountain regions. Under future climate change scenarios (SSP2-4.5 and SSP5-8.5) for the 2050s and 2070s, the model projected a significant upward and northward shift in suitable habitats, coupled with a notable contraction in the extent of highly suitable areas, particularly under the high-emission SSP5-8.5 scenario. The predicted range shifts reflect the species' sensitivity to increasing temperatures and changing precipitation patterns. This suggests a potential loss of suitable habitats in low-elevation and southern parts of its range. Including edaphic factors in the model provided novel insights, specifically highlighting the critical role of soil properties, such as soil pH and nitrogen content, in shaping the ecological niche of E. intermedia. These findings complement the observed upward and northward shifts in habitat suitability under future climate scenarios, emphasizing the species' reliance on high-altitude refugia as climate conditions change. The results underscore important implications for conservation planning, suggesting that strategies should prioritize the protection of these refugial habitats while also considering measures such as habitat connectivity and assisted migration to support the species' adaptation to shifting environmental conditions.