Spatial Analysis of Multiple Ecosystem Service Flows from Natural and Cultural Landscapes in the Ethiopian Highlands
Tegegne Molla Sitotaw is a PhD student in the Department of Natural Resources, Faculty of Geo-Information Science and Earth Observation (ITC). Promotors are prof. A.D. Nelson and prof.dr.ir. L.L.J.M. Willemen from Faculty ITC and co-promotor is dr. D.T. Meshesha from Faculty of Agriculture and Environmental Science, Bahir Dar University.
Ecosystem services are the benefits that humans derive from nature. Natural and cultural landscapes are vital to supporting human well-being, sustaining food security and biodiversity conservation. However, understanding the complex spatial relationships between ecosystem service supply and surrounding benefiting areas through service flow frameworks provides valuable insights for sustainable conservation and restoration of degraded landscapes. Ecosystem service flows from ecosystems to surrounding benefiting areas lack field evidence data, and the spatiotemporal variations of these flows across distances are not well understood. Advances in Earth observation technologies, such as the Copernicus Program, provide valuable opportunities to conduct large-scale ecosystem service assessments using high-resolution satellite data. This thesis empirically explores the role of natural ecosystem remnants in degraded landscapes of Ethiopian highlands in providing key ecosystem services and the effects of ecosystem fragmentation on these services over time. In addition, the uptake of multiple ecosystem service concepts into the national environmental and agricultural policies of Ethiopia was assessed.
The first two studies in this thesis (Ch. 2 and 3) explore the role of sacred forests and wetlands in supporting ecosystem service flows to surrounding areas beyond their boundaries, providing benefits to nearby rural communities. The studies quantify the flow of four key ecosystem services - grass biomass, microclimate regulation, crop pollination, and soil erosion retention - across varying spatial distances. The magnitude and number of ecosystem services decrease with distance, with higher and multiple services closer to natural forests and wetlands.
The third study (Ch. 4) examines the long-term effects of ecosystem fragmentation patterns - such as area, perimeter-area ratio, and proximity - on mapping target ecosystem services over time. The findings reveal that fragmentation, marked by reduced area, increased perimeter-area ratio, and decreased proximity, has a negative impact on ecosystem services over time. This temporal analysis offers critical insights for landscape planning and the conservation of ecosystem services. The final study (Ch. 5) analyses the content of various environmental and agricultural policies, highlighting that while ecosystem services are acknowledged, their integration is inconsistent and fragmented across policy domains. In conclusion, this thesis advances our understanding of the spatial relationships between nature and people. The study emphasises the need for a holistic policy approach that incorporates multiple ecosystem services, aiming to balance nature’s contributions with competing land uses in Ethiopia’s diverse social-ecological systems.
