The Ethiopian southwest is a global origin for Arabica coffee which is the second most traded global commodity after petroleum; and the most important agricultural commodity for Ethiopia. The region is also a global center of crop domestication and diversification with ancient and diverse social and agricultural systems, languages, and cultural groups. People have been here possibly longer than anywhere on Earth and have longer history of interactions with their natural environment, so they rely principally on these agro-ecosystems for a range of goods and services. The forest remnants represent some of the last remnants for the nation and the world's only habitat that retain diverse wild Arabica coffee populations.
However, deforestation and land-use changes have been key drivers of degradation of biodiversity and ecosystem services in the region as in many tropical regions. But, the extent, patterns and drivers of deforestation at local scales in the context of broader socio-ecological dynamics remain poorly understood, although such studies are important for biodiversity conservation and sustainable use of forest resources. I explored land-use changes and forest loss in southwest Ethiopia over the last 40 years (Chapter 1), and the prospects for conserving biological diversity (Chapter 2) and ecosystem services (Chapter 3) in coffee landscapes. Over 40 years, more than 50% of the forest cover has been lost or converted to small-scale and large-scale coffee, Eucalyptus and tea plantations as well as other annual croplands. Deforestation rates varied in space and time as a function of the complex and interacting effects of local socio-cultural processes, and external policy and demographic pressures that influenced socio-ecological feedbacks locally.
To understand the effects of deforestation and fragmentation on biodiversity, I examined patterns of woody plant diversity in the remaining forests, and studied the potential and limitations of conserving native biodiversity in coffee agroforests. There are four types of shade coffee production systems (wild, semi-wild, small-scale garden and plantation coffee) in the region. The wild and semi-wild (small-scale) shade coffee systems retain more native woody biodiversity than large-scale coffee plantations. Although over 60% of woody species and associated biodiversity can be conserved in these shade coffee systems depending on management and the species, some species such as understory shrubs and herbs, slow-growing large trees and lianas cannot persist. While traditionally diverse coffee agroforests can retain some components of native biodiversity, these agroforests are also facing intensification and conversion to working landscapes that support less biodiversity.
In order to reduce deforestation and intensification and conserve biodiversity in these forests and coffee agroforests, it is essential to promote local ecosystem benefits to millions of people living in these ecosystems. I used socio-ecological and market surveys to assess the local benefits of forest-based ecosystem services in both forests and coffee farms, and the prospects for coffee agroforestry systems to provide complementary ecosystem services under current land-use trajectories in the region. My findings show that over 60% of provisioning services can be maintained in coffee landscapes while most of the cultural, regulating and supporting services will have to be provided by the forest remnants. Therefore, both forest remnants and low-intensity coffee landscapes are critical for the persistence of both biodiversity and ecosystem services in the region. This implies that losing these forests to coffee means losing important components of biodiversity and ecosystem services as well as sources for coffee shade tree diversity and for the coffee crop itself. Alternatively, we also cannot lose low-intensity and semi-wild coffee from these landscapes without losing considerable biodiversity and ecosystem services, since coffee is now a large part of these landscapes and forests are becoming scarce.