engleski

Defining chironomid pollution indicators using the best practicable aggregation of species method

As one of the most diverse groups among aquatic macroinvertebrates, chironomids have a great potential to be used in the bioassessment programs of freshwater ecosystems. Nevertheless, they are usually excluded from the list of indicators of organic pollution due to the numerous obstacles concerning their identification process. Therefore, the main goal of this study was to define the indicators of water pollution, facilitating the chironomid identification process. In addition, we wanted to validate the strength of indicators derived from the taxonomic scaling process. The Southern Morava river basin, sampled at 28 sites, has been used as a model, forming a gradient of water pollution. The Best practicable aggregation of species method (BestAgg) has been used to test which taxa are most sensitive to organic pollution. Using the initial data matrix of 114 identified taxa, 15 new entities, which successfully separate groups of sites according to their levels of pollution, were derived using the aggregation process of the BestAgg analysis. The self-organizing map method (SOM) produced clusters ordinating sites along the organic pollution gradient. Out of 15 selected taxa, the Indicator Values Analysis (IndVal) showed that 8 taxa represent sites with high and moderate organic pollution. According to our results, the BestAgg method could be used for defining a new list of reliable indicators with simplified identification process.

Chironomidae; Indicators; BestAgg method

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