Intense use of woody plants in a semiarid environment of Northern Ethiopia: Effects on species composition, richness and diversity

Abstract

Human influences affect plant species diversity and composition in many tropical forest ecosystems. We assess the effects of human use of woody plants on plant species composition and diversity in an intensively used open-access forest in Northern Ethiopia, and compare these community attributes with those of relatively intact forest patches. In each of 90 20 × 20 m plots in the open-access forest, we counted the number of woody plant species in different growth stages, and compared with those of 48 same-sized plots in nearby intact forest patches. Forest utilisation resulted in major shifts in dominance, with the dominant species in relatively intact forests being absent in open-access forest, whereas those species dominant in the open-access forest were absent from intact forests. Open-access forest had a lower total number of species, individuals and beta diversity than relatively intact forests. Intensive forest utilization has resulted in the dominance of disturbance-tolerant native and invasive species. Opuntia ficus-indica, regarded as a problem weed in Ethiopia, was abundant in the open-access forest. Dominance of a few species in the open-access forest could cause local and landscape-scale species loss. Relatively intact forest patches are therefore important for biodiversity conservation and ecological restoration in northern Ethiopia.