Effects of Environmental and Disturbance Factors on Plant Community Distribution in Tropical Moist Afromontane Forests, South-West Ethiopia

Abstract

This study was carried out to investigate the effects of environmental and disturbance factors on plant community distribution in the Majang Forest Biosphere Reserve (MFBR) in south-west Ethiopia. A systematic sample design was conducted to collect vegetation and environmental factors in four study sites. In a nested plot design, the vegetation data were collected from 140 main plots, i.e., 400 m2 (trees), 25 m2 subplots (shrubs, lianas, seedlings, and saplings), and 1 m2 (herbs), respectively. The plant community classification was performed using agglomerative hierarchical cluster analysis (Ward’s Linkage method) in R software (version 4.0.1). The distribution of plant communities along an environmental gradient was computed using canonical correspondence analysis (CCA). In this study, a total of 15 (9.5%) endemic plant species were recorded in MFBR. Four plant community types were identified, and these were Celtis zenkeri-Blighia unijugata, Pouteria altissima-Lecaniodiscus fraxinifolius, Antiaris toxicaria-Celtis toka, and Dracaena afromontana-Cyathea manniana. Environmental and disturbance factors, such as elevations, slopes, harvesting indexes, soil pH, silt, and herbaceous cover, were the most important for determining plant community distribution in the area. Elevation and slope were found to have a significant ( P   <   0.05 ) negative and positive relationship with species diversity and richness, respectively. Therefore, the finding of this study provides baseline information that could be necessary for making further conservation and management in MFBR.