Observed and projected changes in urbanization and nature conservation in a typical fast growing city of Ethiopia, Jimma

Abstract

Urbanization poses a signifcant threat to biodiversity, particularly in developing nations characterized by high rural–urban migration and inadequate urban planning that fails to consider nature conservation. Insufcient information on how to efectively integrate urban expansion and nature conservation exacerbates environmental problems and hampers mitigation eforts. In this study, we assessed the expansion of Jimma City, a typical rapidly growing city in Ethiopia, over the past 35 years, projected changes for the next 50 years, and identifed priority areas for conservation. Landsat satellite images from 1985 and 2020 were utilized to map major land cover types and quantify temporal changes. We employed a Markov chain model to predict changes over the next 50 years and a GIS-based multi-criteria approach to identify conservation priority areas. Our fndings underscore the adverse efect of urban expansion on natural habitats. Over the past three decades, built-up areas expanded by sevenfold (721%; 2227 ha) while croplands expanded by 34% (4155 ha). Conversely, natural habitats experienced signifcant declines: forest cover declined by 39% (5209 ha), grassland by 20% (655 ha) and wetland by 28% (638 ha). Projecting the current trend over the next 50 years showed built-up areas to further increase by about fourfold (436%, 3565 ha). However, open water, wetland, natural forest, and cropland are predicted to decline by 81% (120 ha), 40% (660 ha), 42% (3455 ha), and 55% (8848 ha), respectively. Given the current rate of population growth and rural–urban migrations, urban expansion appears inevitable. Our study emphasizes the importance of designating at least 9040 ha (28%) of the land within the city and its surroundings as high-priority areas for biodiversity conservation. These areas encompass approximately 95% of the remaining forest remnants, 78% of the wetland area, and 22% of the grassland. It is imperative for urban administrations in developing nations to adopt sound policies, strategies, and planning approaches that support the integration of urban development and nature conservation, with special attention given to the preservation of key biodiversity areas. Such eforts are crucial for fostering inclusive, safe, resilient, and sustainable cities. Biodiversity conservation · Remote sensing · Urban expansion · Urban planning · Urban biodiversity · Urban ecosystem