Table_1_Urban sprawl at the expense of cultivated land: decadal land use and land cover changes and future projections in the upper Awash basin of central Ethiopia.DOCX

IntroductionUrban sprawl in developing countries affects future sustainability concerns related to environment, ecology and cropland losses. This study aimed at identifying, classifying and quantifying the changes in land-use and land-cover (LULC) during the last two decades (2000–2020) and predict the decadal pattern for the next three decades (2030–2050), with particular emphasis on urban sprawl at the expense of cultivated land in the upper Awash basin of central Ethiopia.MethodsLandsat images were used to analyze the LULC change dynamics using hybrid image classification and maximum likelihood classifier techniques. The Cellular Automata-Markov Chain (CAMC) Model was used to predict its future LULC change dynamics. A detailed analysis of the urban sprawl in the cities of Addis Ababa, Adama, and Mojo was also conducted.ResultsIt was observed that during the last two decades, settlements, particularly urban sprawls, substantially expanded at the expense of cultivated land, whereas the latter modestly expanded at the expense of forestland, bare land, and shrubland. From its size in 2000, the urban sprawl of Addis Ababa has grown in all directions towards cultivated land by more than six times in 2020 and is expected to become double of that by 2050 in the urban and peri-urban areas of the basin. Adama city has expanded by the same rate of 9.7% in the past two decades, while Mojo town has sprawled 9 folds between 2010 and 2020. The predicted percentage change in settlement for Addis Ababa and its neighboring districts within 22 km radius from the centroid shows a 40% expansion in 2030, 77% in 2040, and 87% in 2050 compared with the reference year 2020. Similarly, the Mojo town will expand significantly in 2030 (54%), 2040 (119%), and 2050 (by a staggering magnitude of 244%), while Adama will expand within the 12 km radius by 18%, 42%, and 117% in the next three respective decades.DiscussionThe rapid cultivated land conversions in the basin may contribute to major shifts in urban and peri-urban ecological environments. Our predictive LULC change maps and urban sprawling could be useful for developing effective and sustainable land-use policies for environmental and ecological management in the upper Awash basin.

本项研究旨在探讨发展中国家城市扩张对环境、生态和耕地损失未来可持续性影响的关注。研究目标在于识别、分类和量化过去二十年（2000年至2020年）土地利用和土地覆盖（LULC）的变化，并预测未来三十年（2030年至2050年）的十年模式，尤其关注埃塞俄比亚中部阿瓦什上游流域因城市扩张而牺牲的耕地。研究方法包括利用Landsat影像，通过混合图像分类和最大似然分类技术分析LULC变化动态，并采用细胞自动机-马尔可夫链（CAMC）模型预测其未来变化动态。同时，对亚的斯亚贝巴、阿达玛和莫乔等城市的城市扩张进行了详细分析。研究结果指出，在过去的二十年里，由于耕地面积的减少，城市扩张尤其是城市扩张在所有方向上向耕地扩展，其规模在2020年比2000年增长了六倍以上，预计到2050年将翻一番。阿达玛城市在过去二十年里以9.7%的速度扩张，而莫乔镇在2010年至2020年间的扩张速度为9倍。预测显示，以亚的斯亚贝巴为中心，半径22公里的区域内，到2030年、2040年和2050年，城市及其周边地区的居住地面积将分别扩大40%、77%和87%，与2020年相比。同样，莫乔镇将在2030年（54%）、2040年（119%）和2050年（以惊人的244%的增长率）显著扩张，而阿达玛在接下来的三个十年内将在半径12公里的区域内分别扩大18%、42%和117%。讨论部分指出，流域内耕地的快速转变可能导致城市及其周边生态环境的重大转变。本研究预测的LULC变化图和城市扩张预测可能对制定上阿瓦什流域环境与生态管理中的有效和可持续的土地利用政策具有重要意义。