2.2.2 Land use and driver data
In the simulation of future land use in China, the land use data were downloaded from the Resource and Environment Science and Data Center (RESDC), including 2010 and 2015. Referring to the classification system of China’s National Land Use and Cover Change (CNLUCC) (Table S2), the land use data in 2015 were reclassified by ArcMap10.5 software, including cultivated land, forest, grassland, waters, construction land, and unused land. The region expressed by the classified grassland (all kinds of grasslands with herbaceous plants and coverage of more than 5%, including shrub grassland dominated by grazing and sparse forest grassland with canopy density of less than 10%) is consistent with the habitat previously recorded by T. chinense , so we regarded the grassland as the natural habitat of T. chinense . The driving factors were divided into physical geography, human disturbance, and bioclimate (Figure S1). Physical geographic factors included elevation (WorldClim Database v2.1), soil erosion (RESDC), and distance from water. Distance from the water was calculated based on water system data (RESDC) using the EuclideanDistance tool in ArcMap10.5. Human disturbance factors included the population data and GDP data of 2015 were downloaded from the RESDC and the distance from road and railway (DRA) calculated by EuclideanDistance tool based on the road data and railway data of RESDC. Bioclimatic factors included annual precipitation and mean temperature data from WorldClim Database v2.1 in 2015. All the above data layers used the Resample tool in ArcMap10.5 to unify the data resolution to 2.5 min.