Tropical Plant Research

Girma Gudesho* and Zerihun Woldu

*Department of Plant Biology and Biodiversity Management, Addis Ababa University, P.O. Box: 3434, Addis Ababa, Ethiopia

DOI: https://doi.org/10.22271/tpr.2022.v9.i1.001

Abstract:
Plant community's distributions are determined by topographic factors, soil composition, and physical factors. This study intended to investigate plant community assembly along topography, age, and disturbance gradients. The higher altitude forest patches of the wombera district were classified into pioneer, intermediate, and climax based on age gradients, canopy height, and layer. Each age classes ranked into disturbance gradients: Intact, medium, and highly disturbed based on intensity, frequency, and severity of disturbances. Every 150–300 meters, transact lines were laid along altitudinal gradients, and plots were laid every 100–150 m along transects. Woody plants' cover abundance, height, and DBH were measured from 54 (20 × 20 m each) nested sampling plots. In five (5 m × 5 m) quadrates nested in the larger quadrates, shrubs, seedlings, and saplings were recorded. In 5 (1 m × 1 m) quadrates nested in the 5 m × 5 m quadrates, herbs and grass species were collected. Agglomerative hierarchical cluster analysis and nested ANOVAs with R software were used to identify plant communities and analyze the relationship between plant richness and diversity along age and disturbance gradients. Woody (85) and herbaceous (65) species were classified into three plant communities. Age (Succession) and disturbance gradients were also determinates of pant communities. Plant species diversity and richness significantly varied along age and disturbance gradients. The RDA result showed that the variation of species distribution and plant community formation was related to age, altitude, and disturbance. The maximum species diversity was found in patches of moderately disturbed forest, followed by intact and highly disturbed forest patches along with disturbance gradients.