|Monitoring wetlands along the ‘Western-Greek Bird Migration Route’ using Landsat and ASTER satellite images: Amvrakikos Gulf (Greece)|
Bortels, L. (2009). Monitoring wetlands along the ‘Western-Greek Bird Migration Route’ using Landsat and ASTER satellite images: Amvrakikos Gulf (Greece). MA Thesis. Vrije Universiteit Brussel: Brussel. 102 pp.
Birds; Migraties; Protection; Remote sensing; Satellite-Sensing; Wetlands; Greece [Marine Regions]; Marien
The west-coast of Greece is an important migration route for African-Eurasian migratory wetland birds, as it is part of the Black Sea/ Mediterranean flyway. The hypothesis at the basis of this research is that loss and/or deterioration of number, area and quality of wetlands along the west-coast of Greece can result in a lack of suitable stopover sites for migratory birds. Labour- and cost-effective methods are needed to monitor these wetlands.The use of remote sensing methods for mapping bird migration habitat along the west-coast of Greece and for temporal monitoring of changes in these habitats was investigated, while the methodology used and the results were meant to form a baseline for future research in this field and in this area.The Amvrakikos Gulf, a coastal wetland complex along the west-coast of Greece, was selected as study area. Landsat TM and ETM+ images and ASTER VNIR images were used to perform a post-classification change detection over a time period of 15 years (1989 - 2004). A classification scheme was developed based on the MedWet classification system. Adaptations to this scheme in order to fit our research objectives were made, following the information retrieved from the satellite images. An unsupervised ISODATA (Iterative Self-Organizing Data Analysis) classification was performed and followed by signature editing, supervised classification and an accuracy assessment of the classification. The post-classification comparison was done with a raster GIS-based matrix analysis. The results showed that Landsat and ASTER VNIR satellite images can be used to trace small wetlands of approximately 0.5 ha. It was found that Landsat and ASTER VNIR satellite images can also be used to monitor changes in wetlands, and in particular marshes, mudflats and aquatic beds, which are important habitats for migratory wetland birds. From 1989 to 2004 there has been a decrease in this class of 32%. Changes occurred from marshes, mudflats and aquatic bed to water surface (25%) and vegetation (7%).In conclusion, the materials and methods used in this research are proposed as helpful tools for the investigation of wetlands. Landsat and ASTER images are easy, reliable and low cost, though research is needed to improve ecological resolution (further characterization of biotopes and habitat types).