Phylogenetic diversity patterns in Himalayan forests reveal evidence for environmental filtering of distinct lineages

Large‐scale environmental gradients have been invaluable for unraveling the processes shaping the evolution and maintenance of biodiversity. Environmental gradients provide a natural setting to test theories about species diversity and distributions within a landscape with changing biotic and abiotic interactions. Elevational gradients are particularly useful because they often encompass a large climatic range within a small geographical extent. Here, we analyzed tree communities in plots located throughout Arunachal Pradesh, a province in northeast India located on the southern face of the Eastern Himalayas, representing one of the largest elevational gradients in the world. Using indices of species and phylogenetic diversity, we described shifts in community structure across the landscape and explored the putative biotic and abiotic forces influencing species assembly. As expected, species richness and phylogenetic diversity decreased with increasing elevation; however, contrary to pr...大规模环境梯度（environmental gradients）对于解析塑造生物多样性演化与维持的核心过程具有不可估量的重要价值。环境梯度为在生物与非生物交互作用动态变化的景观中，检验物种多样性与分布相关理论提供了天然的实验场景。海拔梯度（elevational gradients）的应用优势尤为显著，因其可在狭小的地理范围内涵盖跨度极大的气候区间。本研究对遍布阿鲁纳恰尔邦（Arunachal Pradesh）的样地林木群落展开分析——该邦地处印度东北部喜马拉雅山东段南麓，属于全球规模最大的海拔梯度分布区域之一。研究借助物种多样性与系统发育多样性（phylogenetic diversity）指数，刻画了区域内群落结构的空间变化特征，并探究了影响物种群落组装的潜在生物与非生物驱动因子。正如预期，物种丰富度与系统发育多样性随海拔升高呈下降趋势；但与……相反。