Performance comparison of two biotic indices measuring the ecological status of water bodies in the Southern Baltic and Gulf of Lions.
Two biotic indices, ATZI Marine Biotic Index (AMBI) and Benthic Quality Index (BQI) have been recently introduced within the EC Water Framework Directive to assess the quality of marine habitats: both are based on sensitivity/tolerance classification and quantitative information on the composition of soft-bottom macrofauna. Their performance, especially with regard to sampling effort was assessed based on two data sets collected in Southern Baltic and one from the Gulf of Lions Mediterranean. AMBI was not affected by sampling effort but BQI was. Two modifications were proposed for BQI (i.e., BQI) (1) the removal of the scaling term (i.e., BQI(W)), and (2) the replacement of the scaling term by different scaling term (i.e., BQI(ES)). Both modified BQIs were largely independent of sampling effort. Variability was slightly lower for BQI(W) than for BQI(ES). BQI was highly correlated with BQI(W) and with BQI(ES) both in the Southern Baltic and in the Gulf of Lions. However, the proportions of stations, which were not attributed the same ecological quality status (EcoQ) when using BQI and its two modified forms were always high. Differences in ecological classification were mostly due to the scales used to infer EcoQ. Based on this study we recommend to use BQI(ES) in future studies because it apparently constitutes the best compromise in (1) being independent of sampling effort, (2) limiting the variability in computation in relation with sampling effort, (3) being correlated with BQI and corresponding EcoQ.
Institute for Polar Ecology of the University of Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany. dfleischer@ipoe.uni-kiel.de
Dirk
D
Fleischer
Antoine
A
Grémare
Céline
C
Labrune
Heye
H
Rumohr
Edward Vanden
EV
Berghe
Michael L
ML
Zettler
D000818:Animals; D016208:Databases, Factual; D004784:Environmental Monitoring / Q000379:methods* / Q000592:standards* / Q000706:statistics & numerical data; D007448:Invertebrates; D016014:Linear Models; D008522:Mediterranean Sea; D008954:Models, Biological; D009792:Oceans and Seas; D012680:Sensitivity and Specificity