Vascular plant range size patterns and the relationship with climate and plant richness in Xinjiang region, China

With the regional plant richness distribution data, we explored the plant range size patterns in Xinjiang region of China. We divided Xinjiang into grid cells of 0.1°×0.1°. The plant range size characters, including range area (RA), extent north-south (NS) and extent east-west (EW) were indicated by the grid cells each plant covered. We firstly calculated the range size characters of all vascular plants originated in Xinjiang region. Then the range sizes of plants distributed in a grid cell were overlaid to obtain the range size characters of a grid cell, i.e. , regional patterns. Lastly, the relationship of the range size characters and climate, plant richness were analyzed. We found that in Xinjiang region: Mean RA, NS and EW are 1344, 51 and 89 grid cells and the median values are 366, 42 and 74 grid cells, respectively. The frequency distribution is right-skewed, i.e. , most plant species is of a small range. The range area is positively correlated with extent NS and EW. In the regional scale, RA is smaller in the north than in the south, especially in the Altay mountains and Yili valley of north, and Tarim basin in the south. With the increase of mean annual precipitation (MAP), the range size decreases significantly, while with the increase of mean annual temperature (MAT), the plant range size decreases then increases. The regional plant range size decreases significantly with the increase of plant richness.