干旱区生态环境知识资源中心

Saline and subsaline wetland areas in Central Spain are fragile because of their role in maintaining and controlling environmental quality and biodiversity. The environmental importance of saline wetland areas has been recognized in recent years, due to the increased risk of degradation, and is reflected in the dramatic reduction in wetland cover. We develop a methodological approach to detect temporal and spatial changes of semi-arid wetland components associated with salinization processes, using hyperspectral and multispectral data. Two semiarid wetland sites with different levels of salinity were: a small seasonally hypersaline lagoon and ananthropogenically affected floodplain. Hyperspectral airborne data (DAIS 7915) are used to determine wetland surface cover components (soil, vegetation and water) and selected end members are extrapolated to lower spatial and spectral resolution multispectral Landsat ETM+ and TM data. A spectral unmixing is performed to monitor changing wetland conditions arising from anthropogenic influences. Results show that the methodology is successful in establishing a relationship between land use and land cover. The affected floodplain mainly reflects a monitoring results for the anthropogenically affected floodplain mainly reflects a redistribution of the salt due to management practices. The seasonal hypersaline lagoon shows an important extension of salt efflorescence and although this acts as a natural barrier, there is evidence pointing to encroaching agricultural activity.