Plouzané, France
Plouzané, France

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Ar Gall E.,University of Brest UEB | Le Duff M.,University of Brest UEB
Estuarine, Coastal and Shelf Science | Year: 2014

A quality index Ics (= index of community structure) has been developed as a single numeric descriptor to assess the structural state of macroalgal communities and to evaluate their relative development on rocky shores. Coverage of seaweed species were sampled on the field and treated by taxonomic groups, size classes and structural - functional groups (SFG), giving sub-indices It (= taxonomic index), Is (= stratification index) and Io (= organization index), respectively. Six macroalgal communities corresponding to canopies (belts) distributed vertically on the shore have been investigated for several years in 14 sites of Brittany (France). Communities developing at high topographic levels could be distinguished from those occurring at mid-tide to low levels by Ics values. Communities were globally stable over the sampling period, with few geographical discrepancies. Seasonal or sub-community variations could be tracked by sub-index values. The value of Ics to demonstrate the potential evolution of seaweed communities is discussed by comparison to other quality indices and in the perspective of ecological perturbations. © 2014 Elsevier Ltd.


Ramos E.,University of Cantabria | Puente A.,University of Cantabria | Juanes J.A.,University of Cantabria | Neto J.M.,University of Coimbra | And 7 more authors.
Estuarine, Coastal and Shelf Science | Year: 2014

A methodology to classify rocky shores along the North East Atlantic (NEA) region was developed. Previously, biotypes and the variability of environmental conditions within these were recognized based on abiotic data. A biological validation was required in order to support the ecological meaning of the physical typologies obtained. A database of intertidal macroalgae species occurring in the coastal area between Norway and the South Iberian Peninsula was generated. Semi-quantitative abundance data of the most representative macroalgal taxa were collected in three levels: common, rare or absent. Ordination and classification multivariate analyses revealed a clear latitudinal gradient in the distribution of macroalgae species resulting in two distinct groups: one northern and one southern group, separated at the coast of Brittany (France). In general, the results based on biological data coincided with the results based on physical characteristics. The ecological meaning of the coastal waters classification at a broad scale shown in this work demonstrates that it can be valuable as a practical tool for conservation and management purposes. © 2014 Elsevier Ltd.

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