Woody vegetation composition and structure of church forests in southeast of Lake Tana, Northwest Ethiopia

Understanding woody plant species composition and structure is fundamental to design and optimize the needed conservation measures for Ethiopian church forests. The aim of this study was to describe the composition, structure, and regeneration status of woody species in church forests in southeast of Lake Tana, Ethiopia. Data were collected from twenty-four church forests. Four plots (20 m × 20 m) were established in each church forest. Plots were located in four cardinal directions (north, east, west, and south) at different distances from the forest center. Four subplots (5 m × 5 m) were established in each plot to assess seedlings and canopy cover. In each plot, all woody plants were identified and counted, and diameter at breast height (DBH) was measured. Species and family importance values were computed to characterize the species composition. Additionally, population structural features were analyzed through the variation of tree size classes. Species richness (SR), Pilou evenness (Jʹ), and Shannon–Wiener index (Hʹ) were used to determine species diversity. A total of 115 woody species representing 53 families and 97 genera were found. Of these, 62% were trees, 36% shrubs, 1.89% climber, and 0.06% reed species. Species richness differed among forests, ranging between 16 and 38 species. Fabaceae, Sapotaceae, and Rubiaceae were the dominant families with a high family importance values of 41, 28, and 22, respectively. The church forests have relatively high indices of species diversity (SR = 26 ± 1.25), (Jʹ = 0.75 ± 0.02), and (Hʹ = 2.42 ± 0.07), indicating that they play a major role in the conservation of woody species. However, a relatively high densities of Eucalyptus spp. ranging from 13 to 1925 individuals ha−1 were recorded, and these exotic tree species, thus, form a potential threat to the conservation of native species. The diameter class distribution of some selected keystone and dominant species formed four main shape types, of which the irregular-shaped pattern was most predominant, which suggests missing cohorts and regeneration problems for most species. Higher densities of Eucalyptus plantations were recorded in more recently established than old church forests. Therefore, effective measures should be taken to address the major pressures, such as plantation of exotic species that negatively affect the species composition and vegetation structure of these church forests, which, in turn, affect their ecosystem functions and services.

ISBN:9783030866266

Publication year:2022

Accessibility:Closed