Effects of wild coffee management on species diversity in the Afromontane rainforests of Ethiopia

Coffea arabica L. is native to the Afromontane forests of Ethiopia. The local communities living in and around the forests manage the forest in traditional ways for coffee production. The level of management practices ranges from the relatively undisturbed forest coffee (FC), where little or no human inference is observed to the disturbed semi-forest coffee (SFC) system. This study analyzes the effects of wild coffee management on the floristic diversity and vegetation structure in these systems, in the Berhane-Kontir and Harenna forest sites. A total 114 quadrats, of 20 m x 20 m were laid along transects in both forest sites. Species richness was highest in the FC and lowest in the SFC system although the scale varies between the two forests. Shannon diversity and evenness indices exhibit high variation between the two forest systems and the lowest in the SFC system. The type of growth-form dominance also varies between the two forest systems, with up to 50% reduction in the number of species of lianas, small trees and shrubs were observed in the SFC system. In the SFC system in both forests, coffee plants occupy greater than 88% of plant density in the diameter class between 2 and 10 cm compared to less than 23% in the FC system. The ordination analysis also demonstrates the importance of human management influence and shows clear distinction between the FC and SFC plots of both forests. The continuous wild coffee management in the SFC system suppresses tree regeneration, reduces tree density and eventually leads to the disappearance of forest species, while promoting coffee plants. Therefore, conservation strategies of the Afromontane forest with wild coffee populations should focus on the balance between plant diversity and coffee production. (c) 2006 Elsevier B.V. All rights reserved.