Human disturbances and their impact on woody species diversity in sacred church forests in West Gojjam Zone, Northwestern Ethiopia

Abstract

Church forests are crucial refuges for biodiversity, yet human activities pose significant threats to their survival in Ethiopia. Therefore, a comprehensive understanding of woody species diversity and the effects of disturbances is necessary for effective conservation. This study aimed to investigate human disturbances and their effects on woody species diversity in 26 church forests in the West Gojjam Zone. Different types of human disturbances and vegetation data were collected from 26 church forests. To gather information on trees with a DBH ≥2.5 cm and height >2.5 m, 175 main plots measuring 20 m x 20 m (400 m²) were set up. Within the main plots, 875 subplots measuring 5 m x 5 m (25 m²) and 1 m x 1 m (1 m²) were placed to evaluate saplings and seedlings, respectively. Various types of human disturbances were recorded within these plots. Statistical analyses, including one-way ANOVA and linear regression, revealed considerable variations in woody species richness, with 111 species identified 1.8 % endemic, 15.32 % exotic, and 82.88 % indigenous. Key disturbances like graves, clearings, and grazing significantly impacted these forests. Larger forests and those at higher elevations experienced fewer disturbances, while lower elevation forests closer to population centers were more vulnerable. Edge effects exacerbated ecological challenges by promoting exotic species and altering species composition, leading to reduced biodiversity. Notably, significant changes in woody species abundance were observed across inner, middle, and edge plots. The study underscores the importance of community engagement, restoration projects, and ongoing monitoring to mitigate human disturbances, especially near forest edges, to preserve the ecological integrity of these vital church forests.