Impacts of geographical distances and environmental differences on the beta diversity of plant communities in the dry-hot valley of the Yuanjiang River

Abstract

Beta diversity is the difference in species composition between locations. Recently, much of the published biodiversity research has focused on the assessment of beta diversity because it can be used to investigate community assembly and maintenance of species diversity. In this study, we investigated the impacts of dispersal limitation and habitat on the beta diversity of communities by sampling 41 plots throughout the dry-hot valley of Yuanjiang River. Taxonomic beta diversity and phylogenetic beta diversity were quantified using Jaccard dissimilarity, mean nearest taxon distance (MNTD), and mean pairwise distance (MPD). These indices were then related to the differences in environmental characteristics between sample plots and the geographical distances separating sample plots using multiple regression on distance matrices (MRM) and variance partitioning. The results showed that taxonomic and phylogenetic beta diversity indices significantly increased with the spatial distance and difference in mean annual temperature between communities; ·研究报告· 400 生 物 多 样 性 Biodiversity Science 第 24卷 that taxonomic beta diversity and MNTD were most strongly influenced by spatial distance, whereas MPD was equally influenced by spatial distance and mean annual temperature difference between communities; and that only 11–13% of the variance in beta diversity was explained by the spatial distance and mean annual temperature difference between communities. These results highlight the effects of niche and dispersal limitations on beta diversity, and suggest that dispersal limitation may play a greater role than habitat differences between plant community locations. Additionally, human disturbances may greatly impact species composition along the dry-hot valley of the Yuanjiang River.