Taiwania

Plant diversity and communities along environmental, harvesting and grazing gradients in dry Afromontane forests of Awi Zone, northwestern Ethiopia Afromontane forests support diverse species and provide numerous ecosystem goods and services. There are few studies examining the role of dry Afromontane forests in biodiversity conservation, thus motivating our assessment of plant diversity and communities in five dry Afromontane forests. The objective of the study was to determine plant diversity and communities along environmental, harvesting and grazing gradients. Vegetation data were collected systematically in 80 quadrats (400 m2) with subplots for shrubs and herbaceous species. Biodiversity models and multivariate analyses were employed to determine diversity and community types. Cluster and Redundancy Analyses (RDA) were employed for classification and ordination. The result showed that the forests contained 153 species belonging to 63 families of which six species were endemic. Shannon-Weiner index (H) and its effective number of species in five forests were 2.4 and 11.11, respectively. Modeling diversity and evenness exhibited a declining trend along with an increase in elevation. The harvesting index and grazing intensity correlated negatively with richness and diversity. A cluster analysis coupled with indicator species resulted in four community types. RDA showed that the cumulative variance explained by the first four axes accounted for 14.4% of the species variation. The environmental factors that contributed most to explaining species-environment variation included elevation (37.3%), total nitrogen (13.3%), soil pH (12.2%) and grazing intensity (11.8%). In conclusion, dry Afromontane forests contained considerable endemic species, diversity and community types. However, environmental factors, harvesting and grazing intensity showed significant impacts on diversity and community types. Therefore, an effective management plan is needed for the conservation of biodiversity in the forests.

在埃塞俄比亚西北部阿维地区干旱的非洲山地森林中，植物多样性及其群落沿环境、采伐和放牧梯度展开。此类森林孕育着丰富的物种，并提供众多生态系统服务。目前，关于干旱非洲山地森林在生物多样性保护中作用的研究尚少，因此促使我们对五个干旱非洲山地森林中的植物多样性和群落进行评估。研究旨在确定植物多样性和群落沿环境、采伐及放牧梯度的变化。植被数据在80个样方（400平方米）中系统收集，并设置亚样方以记录灌木和草本植物。采用生物多样性模型和多变量分析方法以确定多样性和群落类型。聚类分析和冗余分析（RDA）用于分类和排序。结果显示，该森林拥有153个物种，隶属于63个科，其中6个物种为特有种。五个森林的香农-威纳指数（H）及其物种有效数量分别为2.4和11.11。多样性和均匀度模型显示，随着海拔的升高呈下降趋势。采伐指数和放牧强度与物种丰富度和多样性呈负相关。聚类分析结合指示物种识别出四种群落类型。RDA显示，前四个主轴解释了14.4%的物种变异。在解释物种与环境变异方面，对物种影响最大的环境因素包括海拔（37.3%）、总氮（13.3%）、土壤pH（12.2%）和放牧强度（11.8%）。综上所述，干旱非洲山地森林拥有大量的特有种、多样性和群落类型。然而，环境因素、采伐和放牧强度对多样性和群落类型产生了显著影响。因此，为保护森林中的生物多样性，需要制定有效的管理计划。