Salt marsh vegetation and mudflat dynamics in the Western Scheldt Estuary through Remote Sensing

Developing innovative monitoring and management methods for transitional environments is a fundamental requirement for future scenarios of climate change. The intertidal zones of estuarine and coastal areas are most exposed to impacts, and because of their inaccessibility and highly dynamic and heterogeneous nature, Remote Sensing is regarded as the best alternative to gather information over vast areas of these habitats.

The Remote Sensing group in ISPRA (Institute for Environmental Protection and Research – Rome, Italy), led by Dr. Andrea Taramelli, focuses on temporal changes in biological and geophysical parameters in dynamic coastal areas. One of the test study sites in the frame of the THESEUS Project on coastal risk assessment is the Western Scheldt estuary.

Ground-truthing represents one of the most important steps in the field of Remote Sensing. Thus, a sampling campaign was performed in July, 2012 on two intertidal areas in the Estuary. The objective was to collect in situ samples and field spectroradiometric measurements coincident with a SPOT-4 optical satellite overpass. In situ reflectance spectra have been collected through an ASD FieldSpec ® 3 Hi-Res Portable Spectroradiometer (provided by VITO - Vlaamse Instelling voor Technologisch Onderzoek; Flemish Institute for Technological Research), together with both vegetation and sediment samples from which to accurately define vegetation zonation, sediment grain size, moisture content, and estimate microphytobenthos biomass through chlorophyll-a content. The ultimate objective of this project will be to provide a robust methodology for remote sensing applications in dynamic coastal areas, in order to improve our understanding of how transitional environments respond to climate change and to develop new methods of monitoring mudflat and salt marsh areas.

The Zeekat vessel on the tidal banks of Saeftinghe
Fig. 1. The Zeekat vessel on the tidal banks of Saeftinghe, right after high tide.

The research group standing in front of the zeekat
Fig. 2. The research group standing in front of the ‘Zeekat’ RIB.

On July 5th, 2012, the sampling campaign took place on ‘Verdronken Land van Saeftinghe’ (Drowned Land of Saeftinghe , 51° 19’ 45.61’’ N, 4° 09’ 56.83’’ E). The group was composed by Prof. Andrea Taramelli and Loreta Cornacchia (ISPRA and ‘La Sapienza – University of Rome’), Filip Vandenberghe (K.U. Leuven), Jeroen Van Wichelen (University of Ghent) and André Cattrijsse and Wim Versteeg from VLIZ (Vlaams Instituut Voor de Zee; Flanders Marine Institute). VLIZ has made a great contribution in the logistics of the campaign by providing a rigid inflatable boat (The ‘Zeekat’, Fig. 1 and 2) to reach the north-eastern part of the study site, which could not have been accessed otherwise, and by supporting in instrument transportation and field measurements throughout the day. The Zeekat has been used to travel in the estuary and arrive directly on the tidal banks where the sampling stations had meant to be set out. We gratefully acknowledge VLIZ for their invaluable supporting service, and for their generous assistance in bringing their expertise and logistic in support and promotion of coastal scientific research.

Article by Loreta Cornacchia