| چکیده انگلیسی مقاله |
The United Nations Environment Programme (UNEP) defines land degradation as the temporary or permanent lowering of the productive capacity of the land. Taking the ecological perspective, Bai et al. (2008) consider land degradation a cumulative environmental issue and define it as a long-term decline in ecosystem function which has to be measured in terms of net primary productivity. Although land degradation by itself is a physical process, the land users and their socio-economic environment are its underlying causes (Stocking and Murnaghan, 2001). Human activity coupled with natural processes can cause the loss of a sustained economic, cultural, and ecological function of the land (Johnson and Lewis, 2007). Land degradation is being assessed based on different definitions, understandings, and demands. Scientific approaches applied to the topic over the past decades with respect to various regions of the world include the employment of indicators, modelling of relevant processes (e.g. soil erosion and forest fires), the Ecosystem Service Concept, and the DPSIR. This review discusses the ongoing land degradation assessment approaches and methods. It critically addresses the following questions: To what extent do the scientific approaches recognize the interdisciplinarity of the topic? How are typical limitations, such as data availability and comparability, especially in developing countries, considered? And how can the problem be observed on different scales? |
