物种多样性的梯度分布格局及其形成机制是当前生态学的研究热点之一，但是以往物种多样性梯度变化研究主要集中在种类组成、物种多样性等方面，很少关注多维功能性状在多样性梯度研究中的价值。本项目以西双版纳热带雨林、哀牢山亚热带常绿阔叶林及玉龙雪山亚高山针叶林为云南典型森林生态系统的代表，基于这三个纬度的大型森林动态监测样地及其对应的海拔梯度样带，将传统纬度和海拔梯度的物种多样性研究与多维功能性状空间相结合，通过量化生态位扩张和生态位填充过程在不同空间尺度、不同个体发育阶段及不同气候带的变化，定量化评估环境过滤和竞争排斥过程在树种多样性梯度空间的相对重要性，从而解析从局域到区域尺度，树种如何从区域物种库被添加到纬度或海拔梯度的生态位空间，并深入揭示纬度和海拔环境梯度上树种多样性格局的成因。本项目的实施将为生物多样性理论做出贡献，并为进一步研究气候变化下植物多样性分布格局的响应机制奠定基础。

Diversity patterns along latitudinal and elevational gradients are central issues in ecology. However, there is little consensus as to what underlying processes affect the latitudinal and elevational patterns of species diversity. Whilst most research of this kind focus on species composition and species richness, little attention has been paid to the relationships between species richness and functional diversity across large-scale gradients, which provides important information regarding the mechanisms driving patterns of biodiversity. We take an approach that examines multidimensional functional space across latitudinal and elevational gradients spanning three typical forest ecosystems in Yunnan province. We quantify the niche space of tree assemblages, constructed from functional traits representing major axes of plant strategy variations. We test hypothesis which explains the latitudinal and elevational gradients of species richness in terms of variations in niche space from local to regional scales, using various life-stages of trees. We compare ecological community hypotheses based on large-scale observational data of tree species richness and functional diversity. This project will contribute to the theoretical development in biodiversity to predict how species distribution patterns will change in response to climate change.