Macrozoobenthos communities of small reservoirs of the Zhambyl region of the Republic of Kazakhstan

Abstract

The benthic fauna of 15 reservoirs located in the territory of the Zhambyl region in the Baizak, Zhambyl, Sarysu and Ryskulovsky districts is characterized. Based on the results obtained, it can be concluded that the benthic fauna of the studied reservoirs is heterogeneous, the species composition of zoobenthos in various reservoirs ranged from 1 (Kosheney reservoir) to 6 (Kenes Lake) taxa. The number was in the range 40–480 copies/m², with a biomass 0.03–27.22 mg/m². The bioproductivity of reservoirs in the Baizak district varied from a very low class of α-oligotrophic type to a high class of β-eutrophic type, the number was in the range 160–480 specimens/m², with a biomass 0.76–27.22 mg/m². In the Zhambyl region, from 3 to 6 invertebrate species were identified as part of the macrozoobenthos. The abundance varied 340–360 specimens/m², with a biomass 7.0–17.99 mg/m². Based on the average indicators of the zoobenthos biomass, the level of productivity of the reservoirs of the Zhambyl district varied from the middle class of the β-mesotrophic type to the elevated class of the α-eutrophic type. The zoobenthos of the reservoirs of the Sarysu district varied from 3 to 6 taxa, the number of zoobenthos in the reservoirs ranged from 80 to 160 specimens/m², the biomass 0.36–1.1 mg/m². The value of the biomass of zoobenthos in the reservoirs of the Sarysu district is characteristic of lakes of a very low productivity class, alpha-oligotrophic type. The species diversity of zoobenthos in the reservoirs of the Ryskulovsky district varied from 1 to 3 species. The number varied 40–80 copies/m², the biomass 0.03–17.33 mg/m². The productivity of the reservoirs of the Ryskulovsky district varied from a very low class of α-oligotrophic type to an increased class of α-eutrophic type. According to the frequency of occurrence in all reservoirs, the class of oligochaetes dominated — 20% of the total number of taxa. The Serensen coefficient of species similarity between benthic communities in the districts was 56%.