Characteristics of the predator-prey interactions and the horizontal distribution of macrozoobenthos in small lakes of different types

The horizontal distribution and quantitative characteristics of macrozooben thos were studied in small lakes of the Darwin Nature Reserve (southern Vol ogda oblast). The aggregation index varied in the open areas of acid lakes, which indicated that communities of small acid water bodies were unstable. The aggregation was the lowest. in the open area of a neutral lake. In aci d lakes, the number and biomass of macroinvertebrates were the highest near the coasts. In the neutral lake, conversely, these values were maximum in open areas and low near the coast due to a strong pressure of predatory inv ertebrates and fish. An aggregating effect of invertebrate predators was ob served near the coasts of lakes of different types.