Caragana versicolor shrub expansion is enhanced by moderate warming but later constrained by climate extremes in the southwestern Tibetan Plateau

Shrub expansion, widely reported in high-elevation biomes, has been typically attributed to regional climate warming. However, the effects of new climate conditions on the range shift of dry high-elevation shrublands, such as in the southwestern Tibetan Plateau, remain poorly understood. We addressed changes in the distribution of a high-elevation shrub species from dry climates, Caragana versicolor Benth., under future climate scenarios in the southwestern Tibetan Plateau using the Maximum Entropy model (MaxEnt) developed using 216 spatially distributed point data. Current climate data and future climate projections from five general circulation models (GCMs) were used to simulate both current and future potential habitats of C. versicolor . Our analysis showed that winter precipitation and temperature, summer temperature, annual and daily temperature variability accounted for 89 % variation in shaping C. versicolor habitat distribution. According to model estimates, the current potential habitats of C. versicolor (based on 1970–2000 climate data) was 18.18 × 10 4 km 2 . Under future climate scenarios, the potential suitable habitat of C. versicolor will increase by 45.16 %, 43.47 %, 37.15 %, and 44.52 % compared with current habitats by the mid-21st century (ca. 2060) under SSP126, SSP245, SSP370 and SSP585 scenarios, respectively. However, ca. 2100, potential habitats will increase only by 2.75 % compared to that in 2060 under SSP126 scenario, and will decrease by 2.03 %, 6.16 % and 15.82 % under SSP245, SSP370 and SSP585 scenarios, respectively. Our results suggested that moderate atmospheric warming is likely to contribute to C. versicolor expansion in the near future but, on the long run, continued warming would constrain this process in dry high-elevation systems. These data may help us anticipate the cascading effects of anthropogenic warming in these vulnerable, dry high-elevation ecosystems.