Figure 1

Locations of the study sites in typical dryland of Northwest China. Our sampling scheme was designed to explore the geographic patterns of plant species in a typical dryland ecosystem, which spans dry-subhumid, semi-arid and arid ecosystems, as demonstrated in the legend. The dataset was provided by the Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences (RESDC) (http://www.resdc.cn), and the maps were created using ArcGIS 10 (http://www.esri.com/software/arcgis).