Predicting the global distribution of Reaumuria songarica under climate change based on optimized MaxEnt modeling

Reaumuria songarica (Tamarixaceae) is a small shrub characterized by its strong resistance to drought, saline-alkali conditions, and wind erosion. To establish a theoretical foundation for its effective protection and utilization, this study investigated the global distribution dynamics of the species under current and future climate scenarios.

Global distribution data for R. songarica, encompassing 278 records, alongside information on 30 environmental and climatic factors were compiled. The Maximum Entropy (MaxEnt) model was employed to simulate the globally suitable distribution areas for the species.

The optimized MaxEnt model demonstrates robust predictive performance (AUC = 0.963, TSS = 0.877). Key variables influencing the distribution of R. songarica include Ultraviolet-B radiation seasonality (UVB-2), mean temperature of the coldest quarter (Bio11), and annual precipitation (Bio12), contributing 37.8%, 30.2%, and 24.9%, respectively. Currently, the total suitable area for R. songarica spans 46.44 × 10⁶ km², with the core suitable zone concentrated in the temperate arid and semi-arid regions of the Eurasian continent. Under future scenarios (SSP126, SSP245, SSP370, SSP585), the potential suitable distribution areas for R. songarica exhibit a continuous reduction trend without any signs of expansion. The rate of reduction significantly increases with higher emission intensities, particularly under the high-emission scenarios of SSP370 and SSP585. The areas of contraction are primarily concentrated in central North America, the periphery of the core region in Central Asia, and the western edges of Eurasia. Center-of-mass migration results indicate that the future core suitable area for R. songarica will shift toward the Central Asia-Xinjiang-Qilian Mountains line in the central-eastern and eastern segments.

This study provides a theoretical foundation for delineating habitat protection areas, facilitating population restoration, managing resources, and implementing regional desert ecological management for R. songarica.