The MMIs were
tested using a separate subset of the data, and the results indicated that the newly developed MMIs
were robust in terms of percentage of sites correctly classified, coefficient of variation, box-separation
ratios, and separation powers. The ecological status was then evaluated based on the MMI scores. The
results indicated that the general ecological status of streams and rivers in the Taihu Basin was rated
lower than “good”, the western hill aquatic ecoregion was rated “fair” and the eastern plain aquatic
ecoregionwas rated “poor”. Moreover, the MMIs showed a significant negative response to an increasing
gradientof disturbance. Therefore, these preliminary MMIs can be used as assessment tools in ecological
biomonitoring and management of the Taihu Basin.