Shifts in suitable habitats and productivity of grassland plant functional groups in Xinjiang under future climate scenarios

Understanding how climate change affects the distribution and productivity of key grassland plant functional groups (PFGs) is crucial for predicting ecosystem dynamics and informing adaptive management strategies to ensure ecological security and sustainable pastoral development. Here, we combined species distribution data with environmental variables (climate, soil, and topography) to model the current and future (2050s, 2070s) potential suitable habitats for three major PFGs of legumes, graminoids, and forbs in Xinjiang under three climate scenarios (SSP126, SSP245, SSP585). We applied the MaxEnt model for habitat suitability modeling and integrated the Random Forest model to estimate forage yield within suitable areas. Our main findings are: (1) The MaxEnt model exhibited high predictive accuracy (AUC > 0.85), ensuring robust projections. (2) The dominant environmental factors influencing distribution varied among PFGs: soil type and precipitation of the coldest quarter for legumes; annual precipitation for graminoids; and precipitation of the driest month for forbs. Under current climate conditions, graminoids possessed the largest suitable habitat area (82.61 × 10 4 km 2 ), while forbs had the smallest (73.64 × 10 4 km 2 ). (3) Future climate scenarios project divergent responses. Legumes are projected to expand northeastward into the Tarim Basin, Altay region, and Turpan Basin, increasing their suitable area by 69.53%. Conversely, graminoids are projected to contract in the Tarim Basin, losing 20.03 × 10 4 km 2 of suitable habitat. Forbs show a mixed response, contracting in the Tarim Basin but expanding in the Kunlun Mountains, with their total suitable area initially decreasing before increasing, exhibiting an overall southwestward shift. Estimated forage yields generally increased with expanding suitable habitat area, with legumes showing the highest productivity. Our findings reveal distinct responses of different PFGs to future climate change. Projected alterations in temperature and precipitation patterns are likely to drive significant changes in the structure of suitable habitats and their productivity. This study provides a scientific basis for developing strategies for sustainable grassland utilization, restoration of degraded grasslands, and managing grass-livestock balance in Xinjiang.