Connotative land degradation mapping: A knowledge-based approach to land degradation assessment

Land degradation mapping is a problem-solving task that aims to provide information for allocating budgets and materials to counter the deterioration of land resources. Typically, it entails the implementation of a set of indicators in a GIS to appraise the severity of land degradation across a territory. Nevertheless, the selection of these indicators has proved to be challenging in practice and often this selection reflects one particular and thus limited perspective of land degradation. Because land degradation is intrinsically complex and involves decisions by many agencies and individuals, land degradation mapping should be used as a learning tool through which managers, experts and stakeholders can re-examine their views within a wider semantic context. In this paper, we introduce an analytical framework, called Connotative Land Degradation Mapping, which aims to depict the meaning of a multiplicity of interacting drivers and effects The CLDM entails the implementation of (1) geographic information systems and multicriteria decision analysis (GIS-MCDA), and (2) geo-visualization. The approach is illustrated through a case study of two urban watersheds in central Mexico. Results showed that the main land degradation drivers in the study area were related to natural processes, which were exacerbated by human activities. The output of the CLDM enabled a better communication of the land degradation issues and concerns in a way relevant for policymakers. (C) 2012 Elsevier Ltd. All rights reserved.