The experience of using the Woodiwiss index and indicators of benthic taxonomic richness to assess the ecological state of water bodies in Petrozavodsk

The article considers the use of the Woodiwiss biotic index to assess the state of water bodies in Petrozavodsk. Sampling was carried out on three water bodies. In each water body, 2 observation points were allocated: the first in the background zone, the second in the zone of direct impact. To increase the representativeness and reliability of the results, power-law models of accumulation of taxonomic wealth S=anb were used, where a is the expected taxonomic wealth in the first random sample, b is the rate of accumulation of taxonomic wealth due to an increase in the number of samples (n). Significant differences in the taxonomic richness of macrozoobenthos communities of the studied water bodies were established. The background plots of water bodies were characterized by a large value of the Woodiwiss index, and a large model parameter a. Apparently, the taxonomic richness of communities is influenced not only by the size and type of water body, but also by organic pollution. This assumption is confirmed by the literature data that as the observation point approaches the city, pollution increases. A hypothesis was put forward about the sufficient sensitivity of the Woodiwiss index to indicate the bottom communities of Karelia. The hypothesis was tested by constructing taxonomic wealth accumulation curves based on the minimum number of taken samples (n = 6). It was shown that when using such a technique, there is no need to select a large amount of test material, which simplifies the procedure and reduces costs. In addition, such a technique is sensitive to changes in the habitat conditions of communities in different habitats within the same water body. It is planned that further research will be directed to testing the methodology for bioindication of habitats with similar levels of impact.