16. Rehabilitation Sites Prioritization on Base of Multisource Remote Sensing Time Series, Erosion Risk, and Woody Biomass Modeling

Identifying the right sites for rehabilitation is an important step for successful restoration programs. This study identified rehabilitation priority sites using multisource datasets covering six decades from 1958 to 2016 in the Tis Abay area, as example for the Ethiopian Highlands. Two sets of B&W aerial photographs (1958 and 1984) and two sets of satellite images (MOMS-02/D2 for 1993 and RapidEye for 2016) were the main input data from which eight land use/land cover (LULC) types were classified. Combination of three cases, such as analysis of LULC changes, erosion risk as well as woody biomass demand and supplies, was considered and employed in a GIS environment for the rehabilitation site prioritizations. The change results show that area covered with woody biomass providing LULC classes decreased by 28% in 60 years. On the contrary, the demand increased from 2316 t in 1958 to 21,280 t in 2016 or more than 900%. The erosion risk analysis shows that over 2000 ha (33%) of the area were exposed to an erosion risk of >256 t ha⁻¹ yr⁻¹. All in all, we found about 1000 ha (15%) of the study area as high to very high priority site for rehabilitation. We discussed options but limitations of concepts for landscape rehabilitations in response of global change, especially global warming, and a rapidly growing population.