Using Earth Observation to update a Natura 2000 habitat map for a wetland in Greece Thomas K. Alexandridis a, * , Efthalia Lazaridou b , Anastasia Tsirika a , George C. Zalidis a a Lab of Remote Sensing and GIS, Lab of Applied Soil Science, Faculty of Agronomy, Aristotle University of Thessaloniki, University Box 259, Thessaloniki 54124, Greece b OMIKRON Ltd, Environmental Department, 53 Martiou Str. Thessaloniki 54248, Greece Received 28 February 2007; received in revised form 19 April 2007; accepted 26 June 2007 Available online 14 March 2008 Abstract The European Habitats Directive 92/43/EEC has defined the need for the conservation of habitats and species with the adoption of appro- priate measures. Within the Natura 2000 ecological network of special areas of conservation, natural habitats will be monitored to ensure the maintenance or restoration of their composition, structure and extent. The European Space Agency’s GlobWetland project has provided remotely sensed products for several Ramsar wetlands worldwide, such as detailed land covereland use, water cycle and inundated vegetation maps. This paper presents the development and testing of an operational methodology for updating a wetland’s habitat map using the GlobWetland products, and the evaluation of the extent to which GlobWetland products have contributed to the habitat map updating. The developed methodology incorporated both automated and analyst-supervised techniques to photo-interpret, delineate, refine, and evaluate the updated habitat polygons. The developed methodology was proven successful in its application to the wetland complex of the AxioseLoudiaseAliakmon delta (Greece). The resulting habitat map met the European and Greek national requirements. Results revealed that GlobWetland products were a valuable contribution, but source data (enhanced satellite images) were necessary to discriminate spectrally similar habitats. Finally, the developed methodology can be modified for original habitat mapping. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Habitat map; Remote sensing; Geographic analysis; Semi-automated methodology; Natura 2000 1. Introduction Habitat fragmentation and destruction have major impacts on biodiversity, with severe economic, biological, societal and ethical consequences (Harris, 2004). In response, the Eu- ropean Union (EU) issued the Habitats Directive 92/43/EEC (EEC, 1992). The aim of this directive is the conservation of natural habitats, and of wild flora and fauna through the estab- lishment of a network (Natura 2000) of special areas of con- servation (SACs) and special protection areas (SPAs). Once designated, Natura 2000 sites are to be protected from deteri- oration and damage. Furthermore, any loss of protected habitats must be compensated for, by restoration or the crea- tion of new ones, of at least the same surface area and equiv- alent ecological value. Monitoring the habitats’ extent and quality is an essential tool towards this aim. In accordance with EU legislation, monitoring and report- ing on the state, trends and pressures on the habitats is re- quired. A wide range of initiatives is being undertaken in this context by the European member states. Specifically, in 2001, member states reported their progress in legal transposi- tion and implementation of the directive, and the establish- ment of the Natura 2000 network. A second report is expected from the member states, including the first assess- ment of conservation status of the habitats and species of com- munity interest that are present in their territory (EC, 2005). Greece has responded to the Habitats Directive with the iden- tification and mapping of habitats within the sites proposed to * Corresponding author. Tel./fax: þ30 2310 991778. E-mail addresses: thalex@agro.auth.gr (T.K. Alexandridis), perivallon@ omikron-ltd.gr (E. Lazaridou). 0301-4797/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2007.06.024 Journal of Environmental Management 90 (2009) 2243e2251 www.elsevier.com/locate/jenvman