Mulugeta Dadi Belete

Ethiopia's Green Legacy Initiative (GLI) is one of Africa's most ambitious large‐scale Nature‐based Solutions. This study applied the Multiscale Hydrologic Ecosystem Services Proxy (MS‐HES Proxy) Framework to evaluate the ecohydrological impacts of GLI across multiple spatial scales—from basin to plot level—within the Rift Valley Lakes Basin (RVLB). The approach integrated key indicators as proxies for ecosystem services: basin‐scale Normalized Difference Vegetation Index (NDVI) for vegetation greenness, subbasin‐scale curve number (CN) analysis for hydrological regulation and plot‐scale Landscape Functionality Analysis (LFA) combined with the Shannon–Wiener Index to assess soil functionality, nutrient cycling and biodiversity. Results showed notable improvements across scales. NDVI increased from 0.48 to 0.53, indicating enhanced vegetation cover, whereas CN declined from 82.62 to 81.60, reflecting reduced runoff and improved flood regulation. At the field scale, soil stability rose from 35% (control) to 50% under GLI and 77.5% with soil and water conservation (SWC); infiltration nearly tripled (16.9% to 65%–68.9%); and nutrient cycling improved from 9%–14% to 46%–69%, reaching 100% under GLI + SWC. Biodiversity (H′) increased from 0.77 to 1.75 under GLI + SWC, peaking at 2.26. The results demonstrate a clear ecosystem‐service pathway: restoring soil stability and hydrological function enhances regulating and supporting services, which in turn strengthen provisioning and cultural benefits. Overall, the study signifies a shift from tree planting towards multifunctional ecosystem restoration. Strengthening community‐based watershed stewardship and long‐term ecosystem management is essential to sustain GLI's ecological and socioeconomic benefits.

Land Use/Land Cover (LULC) change has been a substantial environmental concern, hindering sustainable development over the past few decades. To that end, comprehending the past and future patterns of LULC change is vital for conserving and sustainably managing land resources. This study aimed to analyze the spatiotemporal patterns of landscape dynamics from 1986 to 2022 and predict situations for 2041 and 2058, considering a business-as-usual (BAU) scenario in the Wabe River Catchment. The historical land use image classification employed a supervised technique using maximum likelihood algorithms in ERDAS Imagine, and identified six major land cover classes. For future projections of LULC changes in 2041 and 2058, multilayer perceptron neural network and cellular automata-Markov chain algorithms were utilized, incorporating various driving factors and independent spatial datasets. The findings revealed significant and ongoing LULC dynamics in the catchment, with persistent trends expected. Notably, woodland, built-up areas, and agriculture experienced substantial net increases by 0.24%, 1.96%, and 17.22% respectively, while grassland, forest, and agroforestry land faced notable decreases of 4.65%, 3.58%, and 11.20% respectively from 1986 to 2022. If the current rate of change continues, built-up and agricultural lands will expand by 1.28% and 5.07%, while forest and agroforestry land will decline by 2.69% and 3.63% respectively by 2058. However, woodland and grassland cover will exhibit divergent patterns, with a projected decrease of 0.57% in woodland and an anticipated increase of 0.54% in grassland cover. Overall, the observed changes indicated a shift towards intensive agriculture, built-up area expansion, and potentially adverse environmental consequences such as soil degradation, biodiversity loss, and ecosystem decline. To mitigate these consequences and promote sustainable development, immediate action is necessary, including environmentally friendly conservation approaches, sustainable land management practices, habitat protection, and reforestation efforts, ensuring the long-term resilience and viability of the catchment’s ecosystems.

As one of the responses to the global commitments against climate change, the Ethiopian Government launched a nationwide Green Legacy Initiative (GLI) in 2019, which largely focused on forest tree plantations with some inclusion of fruit trees. Despite its tremendous efforts and investments, its effectiveness and impacts have not been studied. This paper attempted to address this necessity by conducting a cross‐sectional quasi‐experiment in three randomly selected woredas/districts of Lake Hawassa Watershed from August 20 to September 2, 2023. The research hypothesized the likely impacts of GLI on four dependent variables (hydrological regulation, soil stability, nutrient cycling and plant species diversity). To achieve this, the research considered the two variants of GLI practices (plantation with and without soil and water conservation measures) and the corresponding control sites. Having three sites and three treatments with five replications, the study involved a total of forty‐five quadrats of the same size (20 m × 20 m). The first three parameters were analysed using the landscape functionality analysis method, while the fourth employed Shannon's diversity index. Results of ANOVA showed that, on average 87% of randomly selected quadrats were found to significantly improve the local hydrology (runoff potential) (≈ 83.3% with Av. p = 0.012), soil stability (≈100% with Av. p = 0.002), nutrient cycling (≈83.3% with Av. p = 0.017) and plant species diversity (≈83.3% with Av. p = 0.012). The research revealed positive results from the Ethiopian Green Legacy Initiative. The small number of samples is acknowledged as a limitation of the research.

For effective water and land resource management in data-scarce areas, it is imperative to investigate the spatial variability of sediment yield using a rapid, reliable, and affordable approach. The current study demonstrated the use of tools and models viz. Geographic Information System (GIS), Revised Universal Soil Loss Equation (RUSLE), and Sediment Delivery Ratio (SDR) based approach for the assessment of soil loss and sediment yield rate in Lake Hawassa Sub-basin. Input data used were soil, rainfall, digital elevation model (DEM), and land use and land cover change (LULC) maps. The result of the study showed that there was significant and widespread soil loss and sediment yield on cultivated land dominated by moderate, steep and very steep slopes with little vegetation and barren areas. An estimated mean of 16.36 t/ha/year, or 1.97 million tonnes of soil is lost annually by sheet and rill erosion across the Sub-basin. The sediment delivery ratio (SDR) at the outlet of the lake sub-basin was 0.249. Accordingly, the quantified sediment yield at the sub-basin outlet, taking into account the average-based soil loss and sediment delivery ratio, was found to be 4.07 t/ha/year. The annual siltation rate of the lake from these two forms of erosion was found to be 1.01 cm/year. Therefore, depending on the severity of the soil loss, appropriate Best Management Practices (BMP) should be applied to reduce the rate of soil loss and sediment yield to protect the lake and its ecosystem.

Gully erosion is a serious environmental issue in Lake Hawassa Sub‐basin. It has affected a large portion of the catchment, and a large amount of sediment has been transported into the lake. This condition needs to be addressed. However, before conservation techniques are implemented, the gully systems should be mapped, their extent and changes over time need to be measured, and their capacity to produce sediment from their catchments should be determined. The objective of this study were, therefore, to map and analyse the change in gully erosion and quantify the sediment loading rate and sediment yield from the active and connected gullies in Lake Hawassa Sub‐basin using object‐based image analysis (OBIA) with high‐resolution SPOT 5 satellite image of the years 2011 and 2020. This method was integrated with field observation for mapping gully features of the study area, in comparison with automatic digitization carried out with the help of eCogenition Developer Version 9.1 and ArcGIS tools. Overall accuracy and Kappa coefficient were determined and were found to be 85.2% and 0.81, respectively, for the image of year 2020 and 81.1% and 0.76, respectively, for the image of year 2011. Based on the OBIA method, the extent of gullies (in area) were found to be 63.5 km ² in 2011 and 79.9 km ² showing a rapid increase between 2011 and 2020 (an increase of 16.4 km ² (24.4%) in the 10 years considered). The later result shows that 5.53% of the area of the Lake Hawassa Sub‐basin is affected by gully erosion. The maximum gully density in the study area was found to be 589 km/km ² in 2011 and this increased to 884 km/km ² in 2020. The sediment loading rate from the Lake's catchment was found to be in the range of 12.62 to 38.59 ton per hectare per year. The sediment yield from the Lake's catchment was 8.83 to 27.02 t/ha/year. The total annual volume‐based sediment yield at the Lake generated from the gully was 2.39 million cubic meter considering sediment delivery ratio of 70% for fully connected gullies. This result shows that 0.21% of the storage capacity of the Lake was being lost due to sedimentation from the gully system every year. From the result by dividing the total volume of the sediment by the surface area of the lake, one can see that a silt thickness of 2.51 cm was being deposited in the Lake every year.

By recognizing wetland management as an integral part of the EcoLaR (ecohydrology-based landscape restoration) approach, this chapter synthesizes state of the art knowledge on wetland management strategies. As a result, the chapter coins a comprehensive framework called PREE to represent the four synergically operating strategies: Preservation – Restoration – Enhancement & Establishment. The Preservation (P) strategy refers to the acts of avoiding, minimizing, compensating, removing, or preventing the adverse anthropogenic pressure/threats on the wetland; the Restoration (R) element repairs or regains the lost functions; the Enhancement (E) actions increase, modify, heighten, intensify, or improve specific function within the existing wetland system beyond the original natural conditions resulting in more desirable conditions to prevail; and the Establishment (E) strategy indicates the formation of artificial wetlands, for specific ecohydrological functions, where none existed before. Each component of this strategy contributes to the effective management of natural wetland in synergy, and it should be noted that the strategies are neither mutually exclusive nor procedural. Rather, they are in the order of general preference and operate in synergy if applied simultaneously. The chapter also shows application of the framework by applying it on Cheleleka Wetland in the Ethiopian Rift Valley Lakes’ Basin.