By Girma Shumi Dugo
Tropical forest ecosystems harbor high biodiversity, but they have suffered from human-induced disturbances. The main purpose of this post is to share with you the findings of a new paper we’ve published in Biological Conservation, where we’ve looked into the effects of these disturbances, that is, the conservation value of moist evergreen Afromontane forest sites across gradients of site-level disturbance, landscape context and forest history in southwestern Ethiopia.
In order to examine the effect of forest degradation, we surveyed woody plants at 108 randomly selected sites and grouped them into forest specialist, pioneer, and generalist species. First, we investigated if coffee dominance, current distance from the forest edge, forest history, heat load and altitude structured the variation in species composition using constrained correspondence analysis. Second, we modelled species richness in response to the same explanatory variables. A total of 113 species of trees and shrubs, representing 40 families, were recorded from all sites. Our findings show that woody plant community composition was significantly structured by altitude, forest history, coffee dominance and current distance from forest edge. Specifically, (1) total species richness and forest specialist species richness were affected by coffee management intensity; (2) forest specialist species richness increased, while pioneer species decreased with increasing distance from the forest edge; and (3) forest specialist species richness was lower in secondary forest compared to in primary forest. These findings show that coffee management intensity, landscape context and forest history in combination influence local and landscape level biodiversity. We suggest conservation strategies that foster the maintenance of large undisturbed forest sites and that prioritize local species in managed and secondary forests. Creation of a biosphere reserve and shade coffee certification could be useful to benefit both effective conservation and people’s livelihoods.