Data from: Species richness and phylogenetic diversity of seed plants across vegetation zones of Mount Kenya, East Africa

Mount Kenya is of ecological importance in tropical east Africa due to the dramatic gradient in vegetation types that can be observed from low to high elevation zones. However, species richness and phylogenetic diversity of this mountain has not been[Reviewer 1 ask me add “been” here. I accepted.] well-studied. Here, we surveyed distribution patterns for a total of 1335 seed plants of this mountain and calculated species richness and phylogenetic diversity across seven vegetation zones. We also measured phylogenetic structure using the net relatedness index (NRI) and net species index (NTI). Our results show that lower montane wet forest have the highest level of species richness, density and phylogenetic diversity of woody plants, while lower montane dry forest have the highest level of species richness, density and phylogenetic diversity in herbaceous plants. In total plants, NRI and NTI of four forest zones were smaller than three alpine zones. In woody plants, lower montane wet forest and upper montane forest have overdispersed phylogenetic structures. In herbaceous plants, NRI of Afro-alpine zone and nival zone are smaller than those of bamboo zone, upper montane forest and heath zone. We suggest that compared to open dry forest, humid forest has fewer herbaceous plants because of the closed [Reviewer 1 suggested me change here into “because of the closed canopy”. I accepted.]canopy of woody plants. Woody plants may have climate dominated niches, whereas herbaceous plants may have edaphic and microhabitat dominated niches. We also proposed lower and upper montane forests with high species richness or overdispersed phylogenetic structures as the priority areas in conservation of Mount Kenya and other high mountains in the Eastern Afro-montane biodiversity hotspot regions.

肯尼亚山在东非热带区域具有重要的生态价值，因其从低海拔到高海拔区域存在显著的植被类型梯度。然而，目前针对该山地的物种丰富度与系统发育多样性（phylogenetic diversity）的研究仍不够充分[审稿人1建议补充“been”一词，本研究已采纳]。本研究共调查了该山地1335种种子植物（seed plants）的分布格局，并计算了7个植被带的物种丰富度与系统发育多样性；同时利用净相关指数（net relatedness index, NRI）和净种指数（net species index, NTI）分析了系统发育结构。研究结果表明：山地低海拔湿润林的木本植物物种丰富度、种群密度及系统发育多样性均为最高；而山地低海拔干燥林的草本植物物种丰富度、种群密度及系统发育多样性最高。就所有植物类群而言，4个森林带的NRI和NTI均低于3个高山带。在木本植物中，山地低海拔湿润林与山地高海拔林的系统发育结构呈现过度分散模式。在草本植物中，非洲阿尔卑斯带（Afro-alpine zone）与雪线带（nival zone）的NRI均低于竹林带（bamboo zone）、山地高海拔林及石楠灌丛带（heath zone）。我们认为，相较于开阔的干燥林，湿润林因木本植物形成的闭合冠层[审稿人1建议将此处修改为“because of the closed canopy”，本研究已采纳]，草本植物更为匮乏。木本植物的生态位主要受气候调控，而草本植物的生态位则更多由土壤与微生境决定。本研究还提出，物种丰富度较高或系统发育结构呈过度分散的山地低海拔与高海拔森林，应作为肯尼亚山及东非山地生物多样性热点区域（Eastern Afro-montane biodiversity hotspot regions）内其他高山的优先保护区域。