沙漠腹地绿洲植物群落物种与系统发育多样性分布格局及驱动因子

Distribution Patterns and Driving Factors of Species Diversity and Phylogenetic Diversity in Oasis Communities of Desert Hinterland

基于梯度变化的生物多样性研究是生态学的研究热点之一,解析不同梯度下的多样性格局特征及驱动因子对揭示群落动态与构建机制具有重要意义.以克里雅河尾闾达里雅布依绿洲为研究对象,通过划分地表水、地下水梯度(A、B、C)的方式探讨了植物群落物种多样性与系统发育多样性的格局特征,并对多样性格局的驱动因子进行了分析.结果表明:(1)物种多样性在低地表水干扰与浅地下水埋深梯度下(B)最高,地表水干扰的加剧与地下水埋深的增加均会降低物种的多样性;系统发育多样性在低地表水干扰与深地下水埋深梯度下(A)最低,随着地下水埋深的变浅与地表水干扰的加剧,植物群落的系统发育多样性有所提升且系统发育结构愈发分散.(2)系统发育多样性指数(PD)与物种多样性各指数之间均存在显著的相关关系,系统发育结构指数(NRI、NTI)仅与物种均匀度指数(Pielou)存在显著的正相关.(3)随着地表水干扰与地下水埋深梯度的变化,物种与系统发育多样性格局的驱动因子也有所不同.在低地表水干扰与深地下水埋深梯度下(A),土壤有机质(SOM)是驱动物种多样性与系统发育多样性格局的主导因子;在低地表水干扰与浅地下水埋深梯度下(B),驱动物种多样性格局的主导因子为土壤pH,驱动系统发育多样性格局的主导因子除土壤pH外还有全磷(STP);在高地表水干扰与浅地下水埋深梯度下(C),土壤电导率(TDS)是驱动物种多样性与系统发育多样性格局的主导因子.

Biodiversity research based on gradient change is one of the research hotspots in ecology.Analyzing the characteristics and driving factors of diversity patterns under different gradients is of great significance to re-vealing community dynamics and construction mechanisms.In this study,we explored the pattern characteristics of species diversity and phylogenetic diversity under different gradients by dividing surface water and groundwater gradients(A,B,C)and analyzed the driving factors of diversity patterns and structures,using the Daliyabuyi Oasis at the end of the Keriya River as the study object.The results show:(1)Species diversity is highest under the gradient of low surface water disturbance and shallow groundwater depth gradient(B);Phylogenetic diversity is lowest under low surface water disturbance and deep groundwater depth gradient(A),with the shallowing of groundwater depth and the aggravation of surface water disturbance,the phylogenetic diversity of plant communi-ties has increased and the phylogenetic structure has become more dispersed.(2)There is a significant correlation between the phylogenetic diversity index(PD)and each index of species diversity,but phylogenetic structure in-dices(NRI,NTI)were only significantly positively correlated with species evenness index(Pielou).(3)The drivers of species and phylogenetic diversity patterns vary with surface water disturbance and groundwater depth gradi-ents.Under low surface water disturbance and deep groundwater depth gradient(A),soil organic matter(SOM)was the dominant factor driving the pattern of species diversity and phylogenetic diversity;Under low surface water disturbance and shallow groundwater depth gradient(B),the dominant factor driving species diversity pattern is soil pH,and the dominant factor driving phylogenetic diversity pattern is total phosphorus(STP)in addition to soil pH;Under high surface water disturbance and shallow groundwater depth gradient(C),soil conductivity(TDS)was the dominant factor driving the pattern of species diversity and phylogenetic diversity.