Impacts of Climate Change on the Spatial Distribution and Habitat Suitability of Nitraria tangutorum

Nitraria tangutorum (Zygophyllaceae) is an ecologically and economically valuable shrub, locally dominant in the arid and semi-arid deserts of northwest China owing to its exceptional drought resistance and salt tolerance. In this study, environmental variable importance was evaluated within the MaxEnt model using percent-contribution metrics, based on 154 distribution records of N. tangutorum and 14 bioclimatic and soil-related environmental variables. We identified the five key variables of N. tangutorum distribution as follows: Precipitation of the Wettest Quarter (Bio16), Topsoil Sodicity (T_esp), Topsoil Electroconductibility (T_ece), Topsoil Car-bonate or lime content (T_CACO3), and Precipitation of the Driest Month (Bio14). The constructed MaxEnt model was then used to project the potential distribution areas of N. tangutorum under the four Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) for both current climate conditions and future climate conditions (2050s and 2090s). The results indicate that, under present-day conditions, high-suitability areas occur primarily in Xinjiang, Gansu, Qinghai, Inner Mongolia, and Ningxia; in future climate scenarios, the suitable habitat for N. tangutorum is anticipated to shrink by the 2050s but is expected to gradually recover by the 2090s. As time progresses, the suitable habitat areas will generally expand towards higher latitude regions. These findings demonstrate N. tangutorum's strong adaptive potential to climate change and provide a scientific basis for its targeted introduction, cultivation, and long-term management in desert restoration and ecological rehabilitation projects.