Restoration of degraded landscapes for ecosystem services in North-Western Ethiopia

Abstract

Establishing exclosures has become common in Ethiopia, especially in the central and northern highlands, where they serve as a response to persistent forest degradation, affecting forest resources and ecosystem services. We investigated changes in vegetation composition, aboveground biomass and soil properties after establishing an exclosure on degraded communal grazing land in Aba-Gerima watershed, North-Western Ethiopia. We selected 4-yr-old exclosure and paired the selected exclosure with an adjacent communal grazing land. In the exclosure, we recorded 46 plant species representing 32 families, whereas we recorded 18 plant species representing 13 families in the adjacent communal grazing lands. Most of the identified woody species are economically important. We observed significant differences between the exclosure and adjacent grazing land in woody species richness, diversity and evenness. Exclosure displayed higher woody species density, basal area and aboveground woody biomass compared to the adjacent grazing land. Landscape position influenced vegetation composition, richness and diversity in the exclosure and adjacent grazing land. Significant differences between the exclosure and adjacent grazing land in soil properties were detected. The influence of landscape positions on soil properties was not consistent. At foot slope position, in the 0- to 15-cm and 15- to 30-cm depths, soil organic carbon and nitrogen content detected in exclosure were significantly higher when compared to the values observed in the adjacent grazing land. However, differences at mid and upper slope positions were not significant. The results support that the establishment of exclosures on degraded lands could support the restoration of degraded native vegetation and soil properties, which consequently enhance the ecosystem services that can be obtained from degraded lands.

Effects of Land Use and Topographic Position on Soil Organic Carbon and Total Nitrogen Stocks in Different Agro-Ecosystems of the Upper Blue Nile Basin

“…Less soil disturbance, greater vegetation cover, and organic input from grazing animals would improve the SOC in the upper position. Similarly, Mekuria et al [25] reported better vegetation cover and biomass in communal grazing lands in the upper position than in the lower position, which is more easily accessed by livestock that induce changes in SOC. Zhu et al [30] also found an increasing trend in SOC content for cropland and a decreasing trend in grassland from the summit to the lower part of a watershed in China.…”

Effects of sustainable land management interventions on selected soil properties in Geda watershed, central highlands of Ethiopia

“…We followed the judgment sampling method (USEPA (United State Environmental Protection Agency) 2002) to locate representative sampling sites for both treated and control sub-watersheds, landscape positions (upper (3031-3156 masl) and lower (2947-3024 masl)), and land-use types (crop and grazing) at two soil depths (0-15 cm and 15-30 cm) (Wolka et al 2011;Mekuria et al 2018). Consequently, a total of 48 samples were collected (2 sub-watersheds × 2 landscape positions × 2 land uses × 2 depths × 3 replications).…”

Changes in selected soil properties across a chronosequence of exclosures in the central dry lowlands of Ethiopia

“…The result of this study is in line with the findings of Abebe et al (2014) in Siltie area from South Ethiopia who reported significantly greater CEC in eight years old (young) exclosures. Higher CEC was also reported in a four-year old exclosure than adjacent grazing land in Gojam, Northwestern Ethiopia (Mekuria et al, 2018). Exchangeable Ca, Mg, and K varied significantly (P<0.05) between exclosures and the grazing land (Table 6).…”

“…The disturbance of natural ecosystems in Ethiopia causes widespread soil degradation (soil erosion, nutrient depletion, and salinization) (Girmay et al, 2008), and ecosystem services (Mekuria et al, 2018). Particularly, soil loss, nutrient depletion, and a decline in soil quality are some of the manifestations of land degradation (Haile et al, 2006).…”