系统发育多样性是植物群落多样性重要组成部分，反映了群落内部的物种演化历史信息。本研究以青藏高原为研究区，结合植物群落数据和环境数据，分析了植物群落系统发育多样性的空间分异特征及其对环境因子的响应。研究发现：（1）青藏高原植物群落的系统发育α多样性沿经度方向表现出不同的梯度变化；系统发育结构不具有明显的空间分异特征；系统发育β多样性整体偏低，随样方间距离增加而减小。（2）系统发育α多样性指数与结构指数显著负相关，而同类多样性指数之间多表现为正相关。（3）系统发育α多样性主要受到水分制约；低降水量及可能造成的干旱胁迫使物种丰富度降低，但也可能诱导新物种形成。系统发育结构与环境因子没有显著相关性；多数群落的植物物种在短时间内发生了快速演化；部分群落仍处于变化之中，导致NRI与NTI反映的系统发育结构不一致。青藏高原植物群落整体的系统发育差异主要受环境选择过程影响，随环境因子差异增加，群落间的系统发育相似性明显下降。

Phylogenetic diversity is an important component of biodiversity, reflecting the evolutionary history of species within the communities. Taking the Qinghai-Tibet Plateau as the study area, this study analyzed the spatial differentiation of phylogenetic diversity within plant communities and its response to environmental factors by combining plant community data and environmental data. The results showed that: (1) the phylogenetic alpha diversity of Qinghai-Tibet plateau showed a significant change along the longitude direction, while different indexes have different correlations; The phylogenetic structure has no obvious spatial differentiation; The phylogenetic beta diversity is generally low and decreased with the increase of quadrat distance. (2) There was a significant negative correlation between phylogenetic alpha diversity indexes and structural indexes, while there was mostly a positive correlation between homogeneous diversity indexes. (3) The phylogenetic alpha diversity was mainly restricted by water; Potential drought stress caused by rare precipitation reduces species richness, but may also induce new species formation. There was no significant correlation between phylogenetic structure and environmental factors. The plant species in most communities evolved rapidly in a short period of time. Some communities are still in change, resulting in inconsistencies in the phylogenetic structure reflected by NRI and NTI. The phylogenetic differences of plant communities were mainly influenced by environmental selection, and the phylogenetic similarity between the communities decreased significantly with the increase of environmental factors.