Biogeographical patterns and environmental interpretation of plant species richness in the Horqin Sandy Lands

Energy, water, and habitat heterogeneity are important factors for species richness distribution. Based on regional species richness data, corresponding climatic data, and habitat heterogeneity, the species richness pattern of the Horqin Sandy Lands and its dominant factors were studied. Results demonstrated there were 115 families and 1030 species of plants in the Horqin Sandy Lands, which showed significant spatial heterogeneity. With the increase in longitude, species richness decreased at first and then increased, whereas latitude had less effect. Furthermore, the water-energy dynamics hypothesis was most suitable for explaining the species richness patterns in the Horqin Sandy Lands. Our results therefore indicated that water resource availability was the main factor affecting species richness in the Horqin Sandy Lands.