Woody plant species diversity of the coastal forests of Kenya: filling in knowledge gaps in a biodiversity hotspot

The coastal forests of Kenya are global biodiversity hotspots known for rich plant diversity and endemism. They exist as fragmented forest islands, and their current conservation status and quantitative trends in plant diversity are understudied. We investigated these knowledge gaps by providing a comprehensive literature review and comparing to field data collected using standardized sampling protocol. Our goals were to build a robust basis for future analyses, biodiversity monitoring, and to understand the role of fragment area in determining species richness. We recorded a total of 937 woody species belonging to 88 families in 30 forest patches from reviewed and sampled data. Species richness per site from literature review was affected by biases in data scarcity, forest size and variation in sampling methods. In general, large forests reserves of Shimba hills and Arabuko exhibited a high number of cumulative species compared to smaller forest patches. Species-area relationship showed a significant proportion of species richness per forest was determined by forest area, according to Arrhenius model. This study is the first to review forest patch woody plant species diversity knowledge gaps in the coastal forests of Kenya, and the resulting comparison provides the first quantitative overview and foundation of these forests.

肯尼亚沿海森林是全球生物多样性热点（biodiversity hotspot）地区，以丰富的植物多样性和特有性（endemism）著称。它们以碎片化森林岛的形式存续，目前针对其保护现状以及植物多样性量化趋势的研究仍较为匮乏。为填补这一认知空白，本研究通过开展全面的文献综述，并结合采用标准化采样方案（standardized sampling protocol）收集的野外数据进行对比分析。本研究的目标是为后续分析、生物多样性监测构建坚实的研究基础，并阐明片段化面积在决定物种丰富度（species richness）中的作用。通过综述与采样数据，本研究在30个森林斑块中记录了隶属于88个科的937种木本植物。文献综述得到的各调查点物种丰富度受数据稀缺偏差、森林面积以及采样方法差异的影响。总体而言，希姆巴丘陵（Shimba Hills）与阿拉布科（Arabuko）的大型森林保护区的累积物种数量高于小型森林斑块。根据阿伦尼乌斯（Arrhenius）模型，物种-面积关系表明森林面积在很大程度上决定了单个森林的物种丰富度。本研究是首次针对肯尼亚沿海森林斑块木本植物物种多样性的认知空白开展综述，其对比分析结果为该类森林提供了首个量化概览与研究基础。