Assessment of Desertification and Land Degradation Vulnerability in Humid Tropics and Sub-tropical Regions of India Using Remote Sensing and GIS Techniques

Abstract

AbstractThe GIS-based Desertification Vulnerability Index (DVI) model has been used for mapping and assessment of potential vulnerability to desertification and land degradation in the two sites prevailing under different climatic conditions, namely Kasargod district in Kerala (humid tropics) and Virudhunagar district in Tamil Nadu (sub-tropics). The DVI model has executed multivariate statistical indices, namely Climate Index (CI), Soil Index (SI), Vegetation Index (VI), Land Use Index (LUI), and Socio-Economic Index (SEI). These multivariate indices are estimated using multiple geo-environmental and demographical parameters like land use/land cover (LULC), rainfall, soil properties, topography (slope), geomorphic landforms, geological settings, and climatic factors. The Desertification Vulnerability Index (DVI) is calculated using the equation expressed as DVI = (CI * VI * SI * LUI * SEI)1/5. The result shows that the Kasargod district in Kerala is not identified with a higher category of desertification vulnerability, and 8.3% of the total area has no significant exposure. The area extend of 91.4% has been found under lower vulnerability conditions, and 0.23% of the area under moderate susceptibility to land degradation in the site-specific areas include Kodakkad, Timiri, Kilalode, Pullur, Panayal, Pallikere, and Bare due to human-induced activities like deforestation and LULC changes. The sub-tropical area of Virudhunagar district in Tamil Nadu shows that 1.4% of the total area has not fallen under land degradation; however, 65.4% of the area falls under low vulnerability and 33.2% under the moderately vulnerable zone. The spatially estimated area of 1428 km2 (33.2%) is found with moderate vulnerability to desertification. Land degradation in various parts of the district includes Vembakottai, Panaikudi, Narikudi, Sivakasi, Virudhunagar urban proximity, and Aruppukottai, due to severe soil erosion and soil salinization. The 65.42% of the area is noticed as low vulnerability to land degradation; however, the land resources of the various sites are gradually undergoing degradation status due to both natural and anthropogenic activities that become causing adverse impacts on environmental ecosystems. Integrated remote sensing and GIS techniques provide an effective platform for sustainable land resources management on a long-term scale.KeywordsDesertification vulnerability indexLand degradationGIS and remote sensingKasaragod and VirudhunagarSouth India