Ecosystem Services and Land Degradation in Gishwati-Mukura Corridor, Rwanda: Cost-Benefit of Sustainable Land Management Practices

Abstract

Gishwati and Mukura Forests are among the fragile ecosystems that face high rates of land degradation in terms of deforestation, loss of  biodiversity, soil erosion and landslides because of intense agriculture and overgrazing, and mining activities. Sustainable land  management practices are therefore needed for restoring ecosystem services within Gishwati-Mukura Corridor. Four scenarios that have  been considered include (1) business as usual where costs and benefits of the current land use systems were analyzed; (2) landscape  restoration by terracing, agroforestry, use of fertilizers and improved seeds; (3) restoration by planting and retaining exotic species  (eucalyptus); and (4) restoration by planting and retaining indigenous species. Data were collected through the Focus Groups  Discussions. Geographic Information Systems (GIS) analysis helped to calculate the land area for afforestation, grazing, and cropping.  Google Earth image was also used to digitize and estimate the number of households to be compensated. A cost-benefit analysis was  performed to compare the implementation costs of sustainable land management against its benefits. Sensitivity analysis was also  carried out to determine how target variables are affected based on changes in other variables to know the most sensitive parameters  and the land management option that provides the best Net Present Value (NPV). Results show that the restoration by exogenous species  offers the highest economic and environmental benefits with a NPV of 40,690,477.7 USD. This is followed by the sustainable land  management option with a NPV of 34,048,663.7 USD and the business-as-usual scenario with a NPV of 21,915,102.8 USD. The rehabilitation of the corridor by exogenous species is less profitable as it shows a NPV of - 9494381.7 USD. Under all scenarios, the NPV is  more influenced by changes in input and output than the discount rate. However, an increase in input prices leads to higher negative changes in NPV. Moreover, NPV is positively affected by an increase in output prices, implying high demands and high prices for food  products (milk and Irish potatoes). Although maize cropping offers high economic returns to local communities, it requires however huge investments. Local communities can bear the costs of soil conservation and fertility improvement when there is a potential for an  increased yield and good price of their agricultural products.