Identification of global and local components of spatial structure of marine benthic communities: example from the Bay of Seine (Eastern English Channel)

Data from samples of the macrobenthic Abra alba-Pectinaria koreni community of the eastern Bay of Seine (English Channel) collected in winter 1986 are analysed to illustrate the advantages of a novel method of multivariate an alysis of spatial patterns described by Thioulouse et al. (Environ. Ecol. S tat., 2 (1995) 1-14). consisting of local and global approaches. Multivaria te ordination procedures are applied that take spatial components into acco unt explicitly through the construction of a neighbourhood graph between cl osely placed sampling sites, which is then used to M right the data. The re sult is a decomposition of spatial structure on local and global scales. Th is method is for the first time applied to macrobenthic data of this region . It shows the underlying importance of spatial scaling in analysis and pro ves to offer more information than classical ordination methods such as cor respondence analysis, which may confuse the two different spatial scales. G lobal analysis is proposed as a powerful tool to define species assemblages and local analysis as an additional instrument to define partitions result ing from biological interactions. Additionally, this method appears capable of incorporating rare species (which influence classical analyses, often r esulting in their elimination from datasets) by minimising their effects on the global seals and conversely maximising them on the local scale. This a nalysis demonstrates the importance of explicitly incorporating spatial inf ormation into the detection and interpretation of patterns in a macrobenthi c community. (C) 2001 Elsevier Science B,V. All rights reserved.