ECOLOGICAL ANALYSIS OF THE COMPOSITION AND COMMUNITYSTRUCTURE OF THE GORODNICHANKA RIVER AQUATIC INVERTEBRATES(GRODNO, BELARUS)

Abstract

Among watercourses most numerous and least studied bodies of water are small rivers. Small rivers in the city are an
integral part of the urban landscape. In Grodno city (Belarus) the Gorodnichanka river flows through the central part of the urbanized landscape, and performs not only environmental, but also city-forming functions.

The species composition of the Gorodnichanka river aquatic invertebrates is represented by 39 taxa. It is inhabited by
invertebrates, belonging to 5 ecological groups: benthos, nekton, plankton, pleuston, periphyton and 3 trophic groups:
filter feeders, phytophages and zoophages with the predominance of zoophages (16 taxa). Among aquatic invertebrates environmental groups benthic organisms dominate — 16 taxa. Closer to the river mouth the level of anthropogenic load decreases, and the species composition of aquatic organisms increases. Reduction of aquatic organisms ecological groups composition is due to flow rate, gradual increase in the anthropogenic load in the city center.

The analysis of aquatic organisms species composition makes it possible to identify the following ecological complexes:
psammoreophiles, litoreophiles, argilloreophiles, peloreophiles, fitoreophiles. In the Gorodnichanka peloreophiles
represented by 15 taxa prevail.

To assess water quality and the ecological status of the Gorodnichanka river Mayer index has been used. Indicator
groups of aquatic invertebrates in the Gorodnichanka river have been defined. On the basis of the above mentioned we can say that the watercourse under study refers to water bodies of the 3d class water quality, moderately pollutedd.

Table 2. Ref.: 12 titles.