2.1 Data Collection and Preprocessing of Distribution Point Data
A total of 199 distribution records of T. sinense were sourced from various data platforms, including Flora Reipublicae Popularis Sinicae (http://iplant.cn/), Plant Photo Bank of China, and the Global Biodiversity Information Facility (GBIF, http://www.gbif.org). Additionally, our research group conducted field investigations, yielding 121 distribution data points. Consequently, a comprehensive dataset comprising 320 distribution records of T. sinense was compiled.
The coordinate points of T. sinense , denoted by latitude and longitude, were converted into decimal numbers compatible with ARCGIS using standard formulas. The resulting table contained three columns: space, longitude, and latitude, and was stored in CSV format. Subsequently, the distribution data in CSV format were imported into ARCGIS 10.2. By utilizing the ”Data/Display XY data” and ”Data/Export data” functions, a vector file representing the distribution points ofT. sinense was generated. The projection utilized the WGS1984 geographic coordinate system, with each grid layer retaining only one distribution point. This process ensured an accuracy of 2.5 m, facilitated by ENMTTools software. Following the removal of duplicate entries and the mitigation of sampling deviations, a final set of 232 distribution points was selected (Fig. 1).