Assessment of ecosystem service value variation over land use/land cover dynamics in the Beles River Basin, Ethiopia

Abstract

The objective of this study was assess the status of ecosystem service values (ESVs) due to changes in land use and land cover (LULC) in the Beles River Basin of Ethiopia to establish the scientific basis for the actionable needs for enhancing the conservation and sustainable use of ecosystem functions. Satellite images of Landsat 5TM (1986), 7ETM+(2002), and 8OLI-TIRS (2019) were used to evaluate the LULC changes over the years. All images were classified using supervised classification technique of a Maximum Likelihood Algorithm (MLA). Accuracy assessments were performed for each reference year. The LULC types were classified with overall accuracy ranging from 89.3–92.1% with Kappa coefficient of 0.87 to 0.9. The classification result indicated a reduction of forests (71.0%), woodlands (11.2%), and grazing lands (1.8%) conversely, an increase of croplands (3568.0%), water bodies (178.1%), and built-up areas (9.4%) over the past 34 years. The total ESVs in the basin were estimated to be US$ 1,085 billion in 1986, US$ 909.4 million in 2002, and US$ 836.5 million in 2019. The percentage losses of ESVs were 22.9% (US$ 249.3 million) over the past three decades. Individual ecosystem service functions, such as erosion control, climate regulation, nutrient cycling, and water treatment, which were among the largest contributors to total ESVs, have also linearly decreased on their values. In contrary, the value of food production ecosystem service function increased dramatically. We conclude that the decline in ESVs evidences the effects of environmental degradation in the basin. Thus, we recommend further studies of sustainable land management (SLM) options that could ensure sustainable ecosystem services in the basin.