MULTISCALE-MULTISENSOR APPROACH IN STUDYING WETLANDS OF THE

P. KANDUS; H. KARSZENBAUM; M. SALVIA; G. GONZALEZ TRILLA; P. PRATOLONGO; F. M. GRINGS; L. ZOFFOLI

Frascati, Italia

Simposio; Globewetland Symposium; 2006

The Paraná River Delta Region is a huge mosaic of wetlands which covers 17,000 km2 at the final portion of the Del Plata Basin in Argentina. This paper focuses on a brief review about how different sensors and a multi-scale approach bring insight on structural and functional features of wetlands, from regional to a specific ecosystem level in a top-down/botton–up approach. At broad scale, ENVISAT Wide Swath Mode (WSM) imagery along with optical SACCMMRS and the last two decades of Normalized Vegetation Index (NDVI) time series of NOAAAVHRR satellite systems were used to analyze landscape heterogeneity and wetland functioning in the whole region. The influence of "El Niño" flooding events was evaluated in different wetland landscape units. At fine scale, on the Lower Delta, detailed maps were produced using six Landsat Thematic Mapper images obtaining 28 wetland cover classes with an accuracy assessment of approximately 83%. In this region, special attention has also been given to the study of freshwater tidal marshes dominated by Scirpus giganteus. This marsh covers more than 40% of the Lower Delta surface, in the upper portion of the Del Plata Estuary. Net aboveground primary production (NAPP) field measurements were calibrated with NDVI derived from Landsat ETM+ surface reflectance values resulting in the first map of NAPP for the delta marshes. We also addressed the subject of ENVISAT ASAR imagery detecting aboveground biomass variations and water below the canopy.