ЗООЛОГИЯ

An important step in research planning is the choice of methodology. This is especially important for territories which are difficult to access such as in the Arctic, where successive repetitions of field works require significant resources. The methodology utilizing the local fauna has been used over the past twenty years. It provides comparable data on the structure of fauna and species richness for different territories. The purpose of the present study was to assess the “local fauna method” with respect to fauna studies of ground beetles in the Arctic forest-tundra zone. The research was conducted from June 18 2017 to August 30 2017 within the Polar Urals (10 km from the Harp settlement in the Yamalo-Nenets Autonomous Okrug, which is a state of Russia). Carabids were sampled by using pitfall traps on 20 sites. This article will also include the results of our previous research concerning the structure of some local faunas from the forest-tundra zone of Nenets Autonomous Okrug (settlements Nes’, Oma, Khorey-Ver). The results of this study demonstrate the following: 1) the local fauna of the Polar Urals has 85 species of ground beetles from 25 genera, which is 77% of species lists of carabids for a 70-year period of research within the Polar Urals; 2) the local fauna of the Polar Urals has 29% similarity of list species with local faunas from the European part of the Arctic, with similar compositions of zoogeographical groups and life forms; 3) in one research period there was 90% detection of carabids species in the forest-tundra local fauna using the sampling method of pitfall traps within a period of 40 days, conducted at 15 sites, with the predominance of southern types of plant communities (meadows, forests).

The molluscan fauna of the Syoyakha (Zelenaya) River remain poorly explored even though the Syoyakha is one of the biggest rivers on the Yamal Peninsula. The Syoyakha River is remarkable for its high fish stocking capacity and it plays an important role in the seasonal distribution and migration of commercial fish species. Freshwater mollusks are known to be a major component of freshwater ecosystems and they make up a part of the diet of many commercially important fish species. The species composition of the mollusks inhabiting the lower reaches of the Syoyakha River has been studied. Five bivalve species of the family Sphaeriidae were found, namely Sphaerium corneum (Linnaeus, 1758), Pisidium casertanum (Poli, 1791), P. globulare (Clessin in Westerlund, 1873), P. lilljeborgi (Clessin in Esmark et Hoyer, 1886) and P. dilatatum (Westerlund, 1897). In general, the molluscan fauna of the lower reaches of the Syoyakha River are taxonomically poor, which can be considered typical of freshwater invertebrate communities living at high latitudes. Another reason for the decline in species diversity may lie in the absence of any large transit watercourse in the basin in question allowing northward dispersion of the mollusks. The average density of mollusks in the watercourse stretch under study varied from 98.9 ind./m2 to 620.5 ind./m2. P. globulare settlements had the highest recorded density of 1,442.9 ind./m2. The mollusks are confined to clayey, silty and sandy substrates with remnants of vegetation. The fauna is basically formed by widespread Palearctic and Holarctic mollusk species that have adapted to the extreme conditions of the Arctic. The findings may be used for hydrobiological and fishery characterization of the watercourse given that the recorded species of S. corneum, P. globulare, P. lilljeborgi, and P. dilatatum are a major food item for important fish species, such as cisco, vendace, char, muksun, etc.