Zoobenthos of the Pravaya River (Hekhtsirskiy wildlife refuge, Khabarovsk Territory).

Abstract

For the first time, in the period of open water from April to November 2015–2016, seasonal studies of benthos were conducted in the lower course of the Pravaya River (Khekhtsirsky wildlife refuge, Khabarovsk Territory). The bottom fauna contains 17 taxonomic groups of invertebrates belonging to 4 animal types, including the Round and Ringed worms, Arthropods and Mollusks. The occurrence was dominated by amphipods and mayflies. In terms of density and biomass, amphipods (21,0 and 56,1 %) accounted for a significant proportion in the bottom community, chironomids (42,8 %) and oligochaetes (17,9 %) in density. The mean annual density of the zoobenthos is 709 ind./m2, the biomass is 1,27 g/m2. It has been established that in the Pravaya River quantitative indicators of benthos undergo interannual and seasonal changes. It was shown that in November the value of the primary production of periphyton algae in the river may still increase, and the zoobenthos biomass decreases. According to the bioindication data, the ecosystem of the Pravaya River is in good condition (water bodies from the first to fourth degree of quality).