The role of agroforestry intensification in biodiversity conservation in western Ethiopia

Abstract Background Human mismanagement of natural habitats caused the great loss of biodiversity and ecosystem because of their conversion into modified landscapes. On the other hand, agroecosystems are playing vital role in terms of retaining and conserving certain overstorey trees and associated perennial crops in addition to the small fauna. The main objective of this study was to assess the diversity of woody species and vegetation structure in three coffee systems across an increasing farmers’ management intensity in selected research areas of western Wollega, Ethiopia. A total of 72 samples (24 per each management systems) were purposively selected from three districts based on the dominant coffee production system and the level of coffee production, which supposed to affect the diversity of tree species for collecting data on woody species. Plant specimens were collected following standard herbarium technique and identified in the field and at national herbarium. Results A total of 50 woody species were identified. The most abundant shade tree in coffee agroecosystems was Cordia africana. The nonmetric multidimensional scaling (NMDS) ordination and Sorensen distance-based ordination demonstrated that plots of the same coffee system were almost maintained similar species composition and abundance. However, no similar pattern was observed between the coffee systems, except the small overlap in species composition between plantation coffee and garden coffee systems. Diversity of woody species was significantly different among the coffee management systems (P <.0001). Similarly, some of the structural parameters like density, basal area, and shade significantly reduced along the increased coffee management intensity. Conclusions The study found evidence that the intensification of coffee management was not always the source of biodiversity loss; rather, it is an opportunity for conservation of the locally threatened higher plants. Incorporation of coffee shrubs in the degraded lands or remnant forest patches, integrating coffee in the massive afforestation/tree planting programs, and using multipurpose trees in afforestation can be used as an alternative strategy for overstorey plant conservation