Зообентос лососевых рек национального парка «Анюйский» (Хабаровский край, Россия)

Abstract

The fauna of bottom invertebrates in watercourses of the Anyuysky National Park belongs to the rhytron type and is characterised by a large variety of its composition (20 groups in total), of which amphibiotic insects of the lithoreophilous complex make up 80% of the total benthos density and 75% of its total biomass. This is typical of salmon rivers in the south of the Russian Far East. The second largest group is amphipods which play an important role in aquatic ecosystems in the processing of leaf litter and dead bodies of salmon fishes after their spawning. The density of benthic organisms in the watercourses of the Anyuy River basin and Gassi Lake varied from 5 to 18 256 ind./m2, biomass from ˂0.1 to 32.0 g/m2 (on average 622 ± 52 ind./m2 and 1.2 ± 0.1 g/m2). Mayflies and chironomids dominated in density, while amphipods, stoneflies, and caddisflies dominated in biomass. The occurrence of organisms was as follows: chironomids and mayflies (100% each), caddis flies (99%), stoneflies (88%), amphipods and oligochaetes (87% each), other Diptera (82%). Sialidae, Hirudinea, Asellidae, and Hymenoptera (Ichneumonidae) were rare (<10 %). Interesting and rare finds include chironomids Kaluginia lebeteformis lebetiformis Makarchenko and beetles from the family Psephenidae Lacordaire, which live only in rivers with clean and transparent water, fast currents, high oxygen concentrations, low water temperatures, gravel-pebble and stony soils. According to the state of benthic communities, the water quality of the foothill and mountain rivers and streams in the protected area was assessed in the range from class 1 to 3. Changes in the structural characteristics of the zoobenthos in the Bira channel of the Anyuy River caused by anthropogenic impact were revealed.