Using M-AMBI in assessing benthic quality within the Water Framework Directive: Some remarks and recommendations

摘要

Although M-AMBI values change with the addition of new data, we have demonstrated that these changes are < 0.05 in the EQR, in nearly 95% of the total, when using only four samples. These changes lie within the range recommended by the ECOSTAT Group, for the implementation of the WFD. However, we recommend to use M-AMBI at least with a sampling dataset of 50 locations, in order to minimize changes (98.6% of the samples show changes < 0.05 in the EQR values). Using this recommendation, only 5% of the samples could change their classification, with only 2.2% being the change between Moderate and Good status. If the number of samples is 100, these changes can be considered as being negligible (1.4% of the samples). Finally, as Muxika et al. (2007a) suggest, we recommend strongly the use of DA in classifying the ecological status, in order to avoid these problems. FA should be used as a way of deriving EQR values, for further comparisons.