The extents and rates of conversions of ‘natural’ habitats are the non-linear functions of time periods in agroecosystems of west Ethiopia

Abstract

The processes of habitat changes on the time continuum and their impacts on biodiversity were less understood in Afrotropical contexts. For instance, the temporal patterns of habitat conversions and the conservation implications were not well addressed. To fill this gap, we investigated the process of conversions among land use types for the period of 1973–2018 in agroecosystem of west Ethiopia. Here, we analyzed the area gains and losses as proxy measures of temporal ‘natural’ habitat changes. Accordingly, the satellite images with four resolutions were used to detect the cropland, forestland, grazing land, shrub land, bare land, and built-up land use types. Next, we analyzed the habitat dynamics by using the extents of area gains and losses and the annual rate of changes. Our results showed that the ‘natural’ habitats have been significantly decreasing due to the expansion of cropland over the past 45 years. As a result, the annual rates of change are higher for natural habitats (e.g., forest and grazing areas) when compared with that of crop land. The area gains were higher for cropland when compared with other land use types, despite the extents temporally varied. Whereas, the extents of area gains to ‘natural’ habitats (e.g., forest) from cropland, grazing land, and shrub land were much lower. Our overall results suggest that not only the habitat changes per se, but also the processes, extents, and rates of conversions need to be taken into account for effective land use planning and biodiversity conservation in tropical agroecosystems.