A land degradation assessment based on the combination of quantitative and qualitative change of land cover: a case study in Pakistan

Land degradation is a global environmental issue, affecting human sustainable development. The trend of land cover change (LCC) is one of the core sub-indicators of land degradation assessment in Sustainable Development Goal 15.3.1, which is closely related to the quality of land resources and regional ecological environment. Sustainable management of land resources is the basis and premise of sustainable development of human society and economy. In order to more comprehensively assess the land degradation situation from LCC, optimize the land cover (LC) structure and land resource utilization. This paper combines land cover qualitative change (LQaC) (LC type change) and land cover quantitative change (LQtC) (land vegetation cover change) to comprehensively assess land degradation, and applies it to the Pakistan part of the China-Pakistan Economic Corridor. The results showed that land degradation area in Pakistan from 2001 to 2020 was 1.99% (17,550.07km2), of which 1.90% (16,756.35km2) was caused by LQaC, and 0.09% (793.72km2) was caused by LQtC. Land improvement was 10.75% (94,805.65 km2). Land degradation is mainly caused by LQaC, and it mainly in the Indus River Valley and the central and eastern plains, which is significantly affected by human activities. At the same time, we found that in Pakistan: the continuous agricultural expansion (grassland to cropland) and vegetation establishment (unused land to grassland) are accompanied by serious withdrawal of agriculture (cropland to grassland) and vegetation loss (grassland to unused land). The agricultural expansion and the intensification of human activities lead to land degradation. Our assessment suggests that the government should focus on formulating effective land use policies, while protecting the ecological environment and vegetation: improving the productivity of cropland, optimizing the use of cropland resources, and reasonably reclaiming cropland to realize “Land Degradation Neutrality” and sustainable development of land resources in Pakistan.