戴云山物种多样性与系统发育多样性海拔梯度分布格局及驱动因子

Distribution pattern and driving factors of species diversity and phylogenetic diversity along altitudinal gradient on the south slope of Daiyun Mountain

生物多样性的海拔分布格局是生态学研究的热点。海拔作为综合性因子驱动着植物群落的物种、系统发育与功能多样性的空间分布。以戴云山南坡900-1600 m森林植物群落为研究对象,探讨物种多样性、系统发育指数与环境驱动因子的相互关系以及环境因子在群落构建与多样性维持中的重要意义。结果表明:(1)森林植物群落的系统发育多样性与物种多样性沿海拔均呈现中间高度膨胀格局。(2)物种多样性Margalef指数、Shannon-Wiener指数与系统发育多样性指数呈显著正相关,表明物种多样性越高,系统发育多样性也越高。Shannon-Wiener指数与物种多样性指数(Margalef、Pielou、Simpson指数)、系统发育多样性及系统发育结构都存在显著相关性,一定程度上Shannon-Wiener指数可以代替其他指数。Pielou指数、Simpson指数、Shannon-Wiener指数与系统发育结构NRI(Net relatedness index)指数、NTI(Net nearest taxa index)指数存在显著正相关,表明群落优势度、均匀度与系统发育结构相关性较强。(3)土壤全磷含量是影响系统发育多样性和物种多样性的主要驱动因子,土壤含水量是影响Shannon-Wiener、Pielou、Simpson指数的最显著因子,海拔是影响群落系统发育结构的主要因素。海拔是影响系统发育结构变化的主要环境因子,而土壤因子是影响物种多样性与系统发育多样性的主要因素,进一步验证了物种多样性与系统发育多样性的高度相关,结果旨在揭示物种群落空间分布规律。

The elevational distribution pattern of biodiversity is always a hot topic for ecological research. As a Comprehensive factor, the elevation drives the spatial distribution for species composition, phylogeny and functional diversity of plant communities. Taking the forest plant communities ranging from 900 m to 1600 m on the south slope of Daiyun Mountain as the study object, we analyzed the relationship between species diversity and phylogenetic diversity. Then we explored the environmental driving factors for species diversity and phylogenetic indices. Thus we studied the significance effect of environmental factors on the community assembly and biodiversity maintenance. The results showed that:(1) The phylogenetic diversity and species diversity indicated an intermediate high expansion pattern along the elevations.(2) The species diversity Margalef index and Shannon-Wiener index were significantly positively correlated with phylogenetic diversity index, indicating that the higher species diversity is, the higher the phylogenetic diversity is. The Shannon-Wiener index was significantly correlated with species diversity indices(Margalef, Pielou, Simpson index), phylogenetic diversity and structure, and could replace other indices to some extent. The Pielou index, Simpson index and Shannon-Wiener index were significantly positively correlated with the net relatedness index(NRI) and net nearest taxa index(NTI), indicated that the community dominance and evenness were strongly correlated with the phylogenetic structure.(3) Soil total phosphorus content was the main driving factor affecting phylogenetic diversity and species diversity. Soil water content was the most significant factor affecting Shannon-Wiener, Pielou and Simpson indices. The elevation was the main influencing factor affecting phylogenetic structure. Elevation and soil factors jointly drove the species diversity and phylogenetic diversity of forest communities in the south slope of Daiyun Mountain, and thus further verified the high correlation between species diversity and phylogenetic diversity. The results could provide a theoretical basis to reveal the spatial distribution of forest community.