Quantifying smallholder farmers’ managed land use/land cover dynamics and its drivers in contrasting agro-ecological zones of the East African Rift

Abstract

Understanding the relationships between land use land cover (LULC) change and its drivers is essential for designing appropriate strategies for managing and conserving natural resources. This study examined the status, trends, and driving factors of smallholder farmers’ managed land use land cover (LULC) dynamics over the past 30 years (1988–2018) in two contrasting agro-ecological zones (AEZ) of highly-populated Southeastern escarpments of the Ethiopian Rift Valley. Changes in LULC were quantified by integrating field observation, remote-sensing data, and geographic information systems. Landsat images (1988, 2003, and 2018), household surveys (for drivers), and time-series data sources were used to generate the datasets. Results showed that: (1) the total area of 75,246.98 ha (33.79%) was non-linearly changed to various LULC classes. Cultivated land and agroforestry were dominant and increased in humid AEZ from 1988 to 2018. In the same period, waterbody, wetland/marshy, and grass/bushland were dominant and increased in semi-arid AEZ. Cultivated land increased remarkably at the expense of wetland/marshy, woodland, forestland, and grass/bushland in both humid and semi-arid AEZs, and, consequently, bare land was expanded by 1288% in the region. Agroforestry was highly persistent, while forestland was found to be highly susceptible to LULC change. (2) We observed that there was a spatial variation of drivers between humid and semi-arid AEZs. Population growth and landholding size (land fragmentation) were considered to be the main drivers of LULC changes in humid AEZ, while drought/rainfall variability and agricultural investment were the principal drivers in semi-arid AEZ. Ordinary least square (OLS) and binary logistic regression have also confirmed that population density and agricultural investment are the top drivers that significantly influence LULC classes. We conclude that unmanaged population growth, coupled with the continued expansion of cultivated land, have remarkably contributed to the expansion of bare land and decreases vegetation cover. Hence, improving farm-level participatory land-use management is required to recuperate the environment and smallholder farmers’ well-being.