Development and use of radiometric indexes for assessing Mediterranean wetland functions and human well being

Abstract

Wetland ecosystems in Mediterranien regions, especially coastal, are cradles of biological diversity, providing water and primary productivity upon which countless species of plants, animals depend for survival. They offer too recreational activities for human well-being. Recently, remote sensing and Geographic Information Systems tools have been used to assess, monitor wetlands biodiversity and to promote awareness providing technical support to decision makers for conservation and sustainable development of these ecosystems. This research is done in Halk al Minjel sebkha, known as Hergla wetland, located in the center of Tunisia, covering an area of 12 km2 characterized by its landscape diversity. However, this ecosystem is threated by different forms of degradation. To monitor changes in this ecosystem, Landsat 5 and Sentinel 2 images have been used from 2007 and 2017 and two radiometric indexes have been calculated for each year: Normalized Difference Vegetation Index (NDVI) and Normalized Differential Salinity Index (NDSI). By analyzing thematic maps, we can deduce that important spatial and temporal variations are detected for each index and a strong correlation is checked. Interpretation of the results according to climate changes and human factors shows negative effects on wetland function and human well being. Key words: wetland, radiometric indexes, well being