Spatial distribution of tree species richness in Xiaodonggou forest region of the Altai Mountains, Northwest China Hotspots and status of macroecology research Vascular plant diversity on the roof of the world: Spatial patterns and environmental determinants Vertical distribution of algae in semi-desert soil of Shapotou area,Ningxia Hui Autonomous Region Exploring the origin of the latitudinal diversity gradient: Contrasting the sister fern genera Phegopteris and Pseudophegopteris