EPIPHYTIC RECRUITMENT OF SCHEFFLERA ABYSSINICA (A. RICH) HARMS. AND THE ROLE OF MICROSITES IN AFFECTING TREE COMMUNITY STRUCTURE IN REMNANT FORESTS IN NORTHWEST ETHIOPIA

Abstract

Epiphytic recruitment of trees on trees is a form of facilitation allowing trees to escape herbivory and abiotic stress. In terms of survival and reaching the upper canopy sooner, this form of recruitment may be more successful than recruitment from the ground. Hence epiphytic recruitment may play a major role in affecting plant community structure and vegetation dynamics. To this effect, we studied epiphytic Schefflera abyssinica (A. Rich) Harms. density and characteristics in a church forest and the surrounding degraded matrix in northwest Ethiopia using different sampling techniques. The role of suitable microsites was evaluated as a secondary objective. The result showed that no seedling of Schefflera abyssinica was found on the ground. The average density of epiphytic Schefflera abyssinica was much higher than already standing mature trees. Schefflera abyssinica rejuvenates majorly by forming canopy seedling bank on six different kinds of tree species. Rot holes, branch forks and moss layer on the host tree were important microsites for successful establishment. Our result substantiates earlier reports that Schefflera abyssinica does not form persistent soil seed bank. The result also suggests that the spatial configuration of trees in the forest and in the landscape will remain largely the same; however, the dominant species will change as the epiphyte will gradually outcompete the host. Dominance of only one tree species might have a negative effect on the tree community structure of the forest and the surrounding agro ecosystem.