Macrozoobenthos of Communities of Higher Aquatic Vegetation

Abstract

The article presents the results of a comprehensive study of two components of the aquatic biocenosis: its floristic component and benthos in the shallow waters of the Gorky reservoir within the water area of the Yaroslavsky nature reserve. The composition and structure of plant communities at the boundary of the macrophyte belt was assessed, followed by the identification of dominant associations. In parallel, the taxonomic composition and quantitative characteristics of macrozoobenthos were assessed in the main plant biotopes. Plant communities in the water area are represented by two ecological groups: helophytes and hydrophytes. Macrophytes occupy up to 25% of the water area of the shallow area of the studied water body. Most of the plant communities are concentrated in the northern and northeastern parts of the reserve. 11 species of macrophytes belonging to 10 genera and 9 families were noted. In macrophyte communities, 8 typical associations were identified, where benthos sampling was carried out. In the benthos of typical macrophyte associations, 35 lower definable taxa (LTOs) were identified, of which 17 LUTs are chironomid larvae. In the biotope, 11 HOTs were found out of vegetation. The highest species richness of benthic invertebrates was noted in the communities of Butomus umbellatus L. (1753) and Sparganium erectum L. The benthos of plant communities in August 2021 can be characterized as chironomid-oligochaete, while chironomids dominated in the open littoral. Mollusks played a significant role in the formation of benthos in plant communities. The maximum quantitative indicators of benthic invertebrates in general and the abundance of chironomids of the river. Glyptotendipes in particular have been noted in the community of the burr Sparganium erectum. This is probably due to the morphological structure of this plant and the specifics of the formation of the community by this species. The benthos of plant communities was dominated by phytodetritophages–filterers and phytodetritophages–filterers + gatherers, while in the open littoral, phytodetritophages–filterers prevailed. In all studied biotopes, there were no detritophages–gatherers. In general, according to the abundance of macrozoobenthos, the areas of plant communities can be classified as high-nutrient and very high-nutrient.