Benthic biotope index for classifying habitats in the sado estuary: Portugal S. Caeiro a, * , M.H. Costa b , P. Goovaerts c , F. Martins d a IMAR, Department of Exact and Technological Sciences of the Portuguese Distance Learning University, R. Escola Politecnica, 147, 1269-001 Lisbon, Portugal b IMAR, Faculty of Science and Technology of the New University of Lisbon, Quinta da Torre 2829-516 Caparica, Portugal c BioMedware, Inc., 516 North State Street, Ann Arbor, USA d EST, Universidade do Algarve, Campus da Penha, 8000 Faro, Portugal Received 20 April 2004; received in revised form 15 April 2005; accepted 15 April 2005 Abstract An integration of sediment physical, chemical, biological, and toxicity data is necessary for a meaningful interpretation of the complex sediment conditions in the marine environ- ment. Assessment of benthic community is a vital component for that interpretation, yet their evaluation is complex and requires a large expenditure of time and funds. Thus, there is a need for new tools that are less expensive and more understandable for managers. This paper presents a benthic biotope index to predict from physical and chemical variables the occurrence of macrobenthic habitats. Parameters such as sediment type, organic matter, depth, and hydrodynamic parameters were selected, through a discriminant analysis, to compute the index. Other authors have used multivariate methods to determine the benthic biotopes for Sado Estuary. The index proved to be a valid tool to classify and assess the spatial patterns of benthic habitat and to synthesize stress biotope gradients. Ó 2005 Elsevier Ltd. All rights reserved. 0141-1136/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.marenvres.2005.04.002 * Corresponding author. Tel.: +351 213916300; fax: +351 213969293. E-mail addresses: scaeiro@univ-ab.pt (S. Caeiro), mhcosta@fct.unl.pt (M.H. Costa), goovaerts@ biomedware.com (P. Goovaerts), fmartins@ualg.pt (F. Martins). Marine Environmental Research 60 (2005) 570–593 www.elsevier.com/locate/marenvrev MARINE ENVIRONMENTAL RESEARCH