环境过滤和扩散限制对库姆塔格沙漠南缘植物群落β-多样性的影响

Effects of environmental filtering and dispersal limitation on theβ-diversity of plant communities in the south fringe of Kumtag Desert

多样性反映群落之间的物种组成差异,群落β-多样性的形成和维持一直是生态学研究的核心问题。通过对库姆塔格沙漠南缘60个植物群落的调查,结合环境因素和空间距离,通过Mantel分析以及基于距离的多元回归(MRM),分析了环境过滤和扩散限制对研究区植物群落β-多样性及组分的影响。结果表明:库姆塔格沙漠南缘植物群落存在明显的地理衰减格局,群落之间物种组成差异较大,β-多样性高且大部分来自物种更替;环境差异和空间距离对群落β-多样性及更替组分均有显著影响,物种更替对二者的响应与β-多样性保持一致;MRM分析表明,在研究区β-多样性的形成中环境过滤和扩散限制的相对作用存在差异,环境过滤作用对β-多样性及组分的影响超过扩散作用。通过本次研究可以初步确定在库姆塔格沙漠南缘植物群落β-多样性主要由生态位过程与中性过程以及其他未知过程共同控制,其中气候、海拔等生态位因素扮演着比中性过程更为重要的角色。此外,研究区群落β-多样性可能主要由物种更替导致,不同生态过程对群落β-多样性的影响可能主要通过调控群落物种更替来实现。

Beta diversity reflects the difference in species composition between communities.The formation and maintenance mechanism of community beta diversity has been a core issue in ecology.In this study,we investigated 60 plant communities in the south fringe of the Kumtag Desert,and combined with environmental factors and spatial distance.To analyze the impact of environmental filtering and dispersal limitation on beta diversity and components in the study area through mantel analysis and multiple regression on distance matrices(MRM).The results showed that the plant community similarity in the south fringe of the Kumtag Desert had a significant geographical decay pattern.The species composition between the communities was quite different,and the beta diversity was high,which mainly came from the replacement.Environmental differences and spatial distance had significant effects on community beta diversity and replacement,and the response of species replacement is consistent with beta diversity.MRM analysis shows that the relative effects of environmental filtering and dispersal limitation in the formation of beta diversity are different.and the influence of environmental filtering on beta diversity and components exceeded that of diffusion.Through this study,it can be concluded that the beta diversity of plant community in the south fringe of the Kumtag Desert is mainly controlled by niche process,neutral process and other unknown processes,among which niche factors such as climate and altitude play a more important role than neutral process.In addition,the community beta diversity in the study area may be mainly caused by species replacement,and the impact of different ecological processes on the community beta diversity may be mainly achieved by regulating the community species replacement.