A marine Biotic Index to establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments

In this paper, a marine Biotic Index (BI) for soft-bottom benthos of Europe an estuarine and coastal environments is proposed. This is derived from the proportions of individual abundance in five ecological groups, which are r elated to the degree of sensitivity/tolerance to an environmental stress gr adient. The main difference with previously published indices is the use of a simple formula that produces a continuous Biotic Coefficient (BC) which makes it more suitable for statistical analysis, in opposition with previou s discreet biotic indices - not affected by subjectivity. Relationships bet ween this coefficient and a complementary BI with several environmental var iables are discussed. Finally, a validation of the proposed index is made w ith data from systems affected by recent human disturbances, showing that d ifferent anthropogenic changes in the environment can be detected through t he use of this BI, (C) 2000 Elsevier Science Ltd. All rights reserved.