R. Lagring, F. Bazigou, J. C.-W. Chan, R. Merken and N. Koedam

1. OBJECTIVE POST-CLASSIFICATION CHANGE DETECTION CONCLUSIONS Monitoring wetlandsalong the ‘Western-Greek Bird Migration Route’ (Spatio-temporal change detection using remote sensing and GIS in Logarou Lagoon: a pilot study) R. Lagring, F. Bazigou, J. C.-W. Chan, R. Merken and N. Koedam Vrije Universiteit Brussel, Department of Biology, Belgium, e-mail: rlagring@vub.ac.be INTRODUCTION Whether this degradation takes place is insufficiently investigated and is not followed up adequately by the responsible authorities [3]. Also see the poster by Bazigou et al. at this symposium. Long-distance migratory bird populations are declining worldwide. A major cause is the loss of suitable stopover sites during migration [1]. As a Mediterranean peninsula, Greece plays a crucial role as a transit zone for many migratory birds. In this research, the ‘Western-Greek Bird Migration Route’ (Figure 1) was defined as the flyway of birds following the western coast of the Greek mainland during their migration. Along this route, many wetlands are located. During the 20th century, 70% of Greek wetland area have been drained [2]. Further degradation of wetlands along the ‘Western-Greek Bird Migration Route’ can result in a critical lack of suitable stopover-sites for migrating birds. The objective of this research was to design a cost- and labour-effectivetechnique for monitoring ecological change in wetlands along the ‘Western-Greek Bird Migration Route’. Figure 1. Western-Greek Bird Migration Route and location of Logarou Lagoon as defined in this work Figure 2. False Colour Composite LandSat ETM+ 2000-08-22 of Logarou Lagoon RESULTS • Hybrid Unsupervised-Supervised Classification (Figure 3) •  Unsupervised ISODATA classification: 20 classes, 20 iterations, convergence threshold of 95 % •  Cluster merging to 8 classes: using predetermined classification schedule; field survey, aerial images, habitat maps and Google Earth •  Signature evaluation: by analyzing the spectral profiles of each class. • Edited signature files were used to perform a supervised classification • Overall Classification Accuracy and K: 1977 (82.08 %; 0.80), 1989 (79.17 %; 0.76) and 2000 (80.00 %; 0.77) LandSat images of the Global Orthorectified Landsat Data Set: 1977 (MSS), 1989 (TM) and 2000 (ETM+) Pilot study in Logarou Lagoon: 4900 ha, Amvrakikos Gulf area: Ramsar Site and IBA, Western Greece (Figure 2) Method: 1. Hybrid Unsupervised-Supervised Classification: Unsupervised ISODATA (Iterative Self-Organising Data Analysis) classification, signature editing, supervised classification and accuracy assessment [4]. 2. Post classification comparison using raster GIS based matrix analyses function in ERDAS IMAGINE: pixel-to-pixel comparison of each set of two years (1977-1989, 1977-2000 and 1989-2000) [5]. Post classification comparison By comparing the areas per class in 1977, 1989 and 2000 (Figure 4) one immediately notices an increase of ‘Water Surface I’ (Class 1) and a decrease of ‘Aquatic Bed’ (Class 3). Figure 4. Surfaces (in ha) per class in 1977, 1989 and 2000 The matrix analyses reveal more information about these changes. Table 1 is the result of the matrix analysis of 1977 and 2000. It is learnt that of the total area (5102 ha), more than 50 % has changed class. Looking at Class 3 (Aquatic Bed), one can tell that more then 70 % of the Class has changed into another class, mainly into Class 1 (Water Surface). This post-classification comparison shows clearly the dynamism of the wetland system in Logarou Lagoon. Figure 3. Hybrid unsupervised-supervised classified maps for 1977, 1989 and 2000 • A technique for detecting change in wetland area has been designed using freely accessible LandSat images obtained via the Global Orthorectified Landsat Data Set. • Pilot study on Amvrakikos Gulf (Greece) : • Logarou lagoon is a very dynamic system, where habitats easily convert from one class into another at a decadal scale. The most important human-induced change between 1977 and 2000, was the construction of an aquaculture plant (± 420 ha) in a marsh area (± 800 ha) that probably affected the fauna and flora. • The methodology is cost- and labour-effective, reliable and feasible for detecting changes in areas of wetland ecosystems. Therefore it could be used to investigate all wetlands in Greece. It proves that there is no technological limitation for efficiently following up the existence and extent of wetlands which are important for the required conservation of wetland birds. References 1. Berthold P., 2001. Bird Migration: a general Survey. Second Edition. Oxford University Press Inc. New York, USA. 253 pp. 2. Commission of the European Communities, 1995. Wise use and conservation of wetlands. Communication from the Commission to the Council and the European Parliament. Document COM(95) 189 final. Office for Official Publications of the European Communities. Luxemburg, 54 pp. 3. Bazigou F.M., 2007. The legislation regarding the Western Greek section of the wetland bird migration routes: a preliminary analysis of its adequacy and its implementation. Thesis Ecological Marine Management, Vrije Universiteit Brussel, Brussels, Belgium. 157 pp. 4. Tağil Ş., 2007. Quantifying the change detection of the Uluabat Wetland, Turkey, by use of Landsat Images. Ekoloji 16, 64: 9-20. 5. Haack B.N., Rafter A., 2006. Urban growth analysis and modeling in the Kathmandu Valley, Nepal. Habitat International 30: 1056–1065. Table 1. Change detection matrix of the period 1977-2000