THE ASSESSMENT OF SENSITIVITY OF BIOTIC INDICES IN DETERMINING SYMPTOMS AND LEVELS OF DISTURBANCE USING MACROBENTHIC ASSEMBLAGE DATA

Abstract

a large number of techniques, including a variety of indices, have been proposed and developed for
assessment. Structural and functional variability have been summarized through both univariate and
multimetric indices as integrative indicators in environmental monitoring programs. In general, multimetric
indices are considered to be sensitive, stable, and robust, thus offer a promising approach for ecological
assessment. This study is aimed to assess the degree of sensitivity for several indices in terms of their ability
to determine environmental changes. Based on macrofaunal data, several univariate and multimetric indices
were used to assess and compare the level of disturbance at fallowed farm and reference (control) sites. The
two multimetric indices, the AZTI’s Marine Biotic Indices (AMBI) and Ecological Quality Ratio (EQR), were
used as integrative indicators to assess the categorisation of each sampled site. The results showed that a
combination of multimetric index and univariate indices provide a better assessment. The categories
determined by multimetric indices seem to be in accordance with level of disturbance expressed by the
trophic analysis, multivariate and graphical analyses used in this study. The AMBI has the ability to detect
large scale differences among sites. However, AMBI was unable to discriminate slight changes in the
macrobenthic assemblages between sites, as have been exposed by EQR.