Abstract

         The montane rainforests of Ethiopia are the only places of origin and genetic diversity for Coffea arabica species. These natural forest areas with the occurrence of wild coffee gene pools are however under constant threats, largely due to anthropogenic activities. The study aims to determine the variability in plant compositions and growth of wild Coffea arabica trees in the natural forests of southeastern and Southwestern Ethiopia. The data were collected at twelve study sites. The dominant plants were broadly classified into three forest canopy strata with varying vegetation coverage among and within the study forests. The average abundance of large shade trees, wild coffee plants and shrubs was highest at Berhane-Kontir, Yayu and Bonga natural forests, respectively. The frequency of the respective plant forms was highest at Birhane-Kontir (61%), Harenna (53%) and Bonga (68%). The occurrence of the semi-domesticated spices crops was higher in the Bonga and Berhane-Kontir forests. The average plant density followed the descending order of Bonga>Yayu>Birhane-Kontir>Harenna forest, largely reflecting anthropogenic impacts. There was negative association between the growth of the coffee trees and the undergrowth shrubs. In contrast, the upper canopy large trees and coffee plants had direct relationships. However, the vegetative and reproductive growth responses of wild coffee plants were impaired, partly due to the multiple stresses in the dense forest ecology. Consequently, more than 70% of the total surface area of coffee trees did not bear crops and altogether coffee yield was low. The highest and lowest reproductive efficiencies were obtained from the Harenna and Yayu wild coffee populations, demonstrating the levels of coffee forest management practices. Overall, our findings indicated great variations in the patterns of plant co-existences and growth natures of wild coffee trees and underlines in multiple benefits of coffee forest environments, among others, as natural coffee gene pools. This depicts the need for multi-site in situ conservation and environmental management planning for sustaining biodiversity conservation and maintaining ecosystem goods and services in Ethiopia and worldwide.

Key words: Biodiversity, Ethiopian wild coffee, genetic conservation, natural coffee forest, plant composition.