Abstract Desertification is an issue of environmental concern in Nigeria, particularly the northern part of the country. This study examines land cover changes related to the process of desertification in the states along the northern boundary of Nigeria (Sokoto, Zamfara, Katsina, Jigawa, Yobe, and Borno) and the implications on the Lake Chad Basin. A time series of Landsat imagery at a spatial resolution of 30 m was used over the period from 1984 to 2016. The imageries were subjected to maximum likelihood classification for the purpose of extracting the land cover and analysing the change. Also, the areal extent of vegetation cover within the 32-year period was calculated annually. Using Pearson's correlation analysis, the relationship between the vegetation cover and rainfall was assessed as well as temperature and population density. Results show that 45,945.08 km2 of vegetation cover was lost within the study area including the Lake Chad area between 1984 and 2016. The annual rate of change varied across the different feature classes; the built-up area had the highest rate of increase of 13.68% and 2.65%, from 1984 to 2000 and 2000–2016 respectively. Bare-land increased at the rate of 0.96% and 0.28% from 1984 to 2000 and 2000–2016 respectively while vegetation had the highest rate of decrease of 2.18% and 2.02% from 1984 to 2000 and 2000–2016 respectively. A pattern of vegetation loss was observed as a large expanse of vegetation cover was lost across the north-west and the north-east regions including the Lake Chad area. It was also shown that the magnitude of vegetation cover correlated negatively with temperature and population density but with no significant correlation with the rainfall. The study recommends that the Federal Government should ensure the full implementation of the Great Green Wall project which is aimed at mitigating the rapid sprawl of natural land degradation processes and desertification in the northern boundary states.

中文翻译：

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土地覆盖变化对尼日利亚北部荒漠化的影响以及对乍得湖流域的影响

摘要 荒漠化是尼日利亚，特别是该国北部地区的一个环境问题。本研究考察了与尼日利亚北部边界沿线各州（索科托、赞法拉、卡齐纳、吉加瓦、约贝和博尔诺）荒漠化过程相关的土地覆盖变化以及对乍得湖盆地的影响。使用了 1984 年至 2016 年期间空间分辨率为 30 m 的时间序列 Landsat 影像。为了提取土地覆盖和分析变化，对影像进行了最大似然分类。此外，每年计算 32 年内植被覆盖的面积范围。使用 Pearson 相关分析，评估了植被覆盖度与降雨量以及温度和人口密度之间的关系。结果表明，1984 年至 2016 年间，包括乍得湖地区在内的研究区域内植被覆盖损失 45,945.08 平方公里。不同要素类的年变化率不同；建成区面积增幅最高，分别为1984-2000年和2000-2016年，分别为13.68%和2.65%。1984-2000年和2000-2016年裸地分别以0.96%和0.28%的速度增加，而植被减少率最高，1984-2000年和2000-2016年分别为2.18%和2.02%。随着包括乍得湖地区在内的西北和东北地区大片植被消失，观察到了一种植被丧失模式。还表明，植被覆盖的大小与温度和人口密度呈负相关，但与降雨量没有显着相关性。该研究建议联邦政府应确保全面实施绿色长城项目，该项目旨在减缓北部边界州自然土地退化过程和荒漠化的迅速蔓延。