Effects of geographical distance and differences in climate and altitude on species dissimilarity of vascular plant communities in the dulongjiang river watershed area

Abstract

Species dissimilarity mainly reflects temporal and spatial variation in community composition. Its relationship with random and deterministic factors reveals community assembly, biodiversity formation, and maintenance mechanisms. In this study, we analyzed relationships between species dissimilarity of plant communities and influencing factors in the Dulongjiang River Watershed Area. Jaccard species dissimilarity, geographic distance, difference in climate (Mean Annual Temperature and Mean Annual Precipitation), and altitude between any two communities were calculated. Results showed that the species turnover rate varied from 0.42 to 1. Species turnover significantly linearly increased with Ln-transformed geographic distance and differences in climate and altitude. Results from partial regression analysis showed that these three kinds of factors together can explain nearly 30% of species differences of vascular plant communities in the Dulongjiang River Watershed Area; independent effects of geographical distance, elevation difference, and climatic differences were 18.80%, 3.47%, and 0.10%, respectively. Species dissimilarity in the Dulongjiang Watershed Area results from the combination of environmental and dispersal limitations, which plays an important role in the conservation of plant biodiversity in the Dulongjiang Watershed Area. When biodiversity conservation is undertaken in the area, on the basis of considering the impact of environmental factors, the effects of topographical barriers and dispersal abilities of propagules should be fully considered.