Environmental filtration and dispersal limitation explain different aspects of beta diversity in desert plant communities

Environmental filtration and spatial processes are associated with variation in ecological communities and biodiversity; however, their relative importance to species beta diversity at different sampling scales has not been fully explored in desert plant communities. We examined the relative contribution of environmental and spatial factors to variation in species beta diversity and its components at different sampling scales in the Ebinur Lake Basin through variance partitioning and multivariate analysis. Our results suggested that the beta diversity and its component values decreased with the increase of the sampling scale. Differences in the contributions of the two components to beta diversity at different sampling scales were observed. Environmental filtration and dispersal limitation explain beta diversity on different scales, as well as different components: for different sampling scales, dispersal limitation has a greater impact on species beta diversity on small and medium sampling scales, while environmental filtration plays a dominant role on a large scale; for the different components, environmental filtering better explained the total beta diversity and species turnover, while dispersal limitation had a greater effect on the species nestedness. Our study further confirmed the importance of sampling scales in the quantitative evaluation of pattern formation and driving forces of beta diversity. Moreover, it emphasized the necessity of integrating multiple scales in aggregate community and biodiversity studies.