A comparative analysis of indigenous and exotic tree species management practices in agricultural landscapes of Southwest Ethiopia

Abstract

A substantial tree planting from exotic tree species has been practiced in Ethiopia during the last ten decades. Yet, the efforts made to restore degraded areas using exotic tree species but with less emphasis given to the indigenous tree species for enhancing biodiversity conservation and ecosystem services could not bring the desired results. The aim of this study was, therefore, to undertake the comparative analysis of indigenous and exotic tree species management practices across landuse types in agricultural landscapes of southwest Ethiopia. Five rural kebeles were purposively selected from three districts of Jimma zone based on the status of tree planting practices. Similarly, after the households who possessed five landuse types were identified, 2−9 households were randomly selected from each rural kebeles and in total 31, 18 and 19 households were proportionally selected from the three districts of Mana, Kersa, and Seka Chekorsa respectively. A complete tree assessment was undertaken in five landuse types (homegarden, crop land, woodlot, grazing land and farm boundary) of the households. In total, 340 landuse plots were assessed. A Shannon-Weiner diversity index (H’) was computed to compare species diversity of both indigenous and exotic tree species across landuse types. One-way ANOVA was employed to test the variation in species richness and diversity among landuse types. The result showed that a total of 44 tree species (33 indigenous and 11 exotic) belonging to 29 families were identified and recorded. The species diversity of indigenous and exotic trees significantly varies among landuse types. The diversity of indigenous tree species was higher in homegardens and crop lands but no species was recorded in woodlot landuse type. On the other hand, the diversity of exotic tree species was higher in homegardens but no species was recorded in grazing land. Our results highlight that the existing traditional practices of managing indigenous and exotic tree species by smallholder farmers in their farming systems are among the key considerations that need to be further strengthened in designing biodiversity conservation strategy in the agroecosystems of southwestern Ethiopia.