Woody species diversity and structure across coffee agroforestry systems, natural coffee forest and wealth categories in the Yayu Coffee Forest Biosphere Reserve, Southwest Ethiopia

Coffee agroforestry systems and natural coffee forest are generally seen as beneficial for biodiversity conservation, but this may not always be the case. While coffee agroforestry systems and natural coffee forest are widely recognized for their biodiversity conservation values, the impact of them together with households’ wealth categories on woody species diversity, composition and structure is still remain gap. This study examined the impact of coffee agroforestry systems, natural coffee forest and wealth status on woody species diversity and structure in the Yayu Coffee Forest Biosphere Reserve, Southwest Ethiopia. Three coffee systems were considered for the study, namely natural coffee forest, semi coffee forest, and homegarden coffee. In all, 90 sample plots were randomly selected and surveyed. A total of 27 woody species belongs to 17 families were recorded. All diversity indices, confirmed significantly higher biodiversity in natural coffee forest. Wealth class influenced species diversity, with richer households maintaining significantly higher species richness (p < 0.001). The general linear model showed the interactions of determinant variables had significantly positive effects on biodiversity values (p < 0.001). Structural characteristics such as DBH was significantly greater in natural forest coffee (p < 0.05). Similarly, Semi Forest coffee had significantly the highest basal area (p < 0.05). The highest stem density was recorded both at natural forest coffee and semi forest coffee with no significant difference between them (p > 0.05). Rarefaction analyses confirmed adequate sampling coverage. The findings emphasize the highest significant role of natural forest coffee and semi forest coffee among with rich wealth class for biodiversity conservation.