Tanasevitch A.V.1, Rybalov L.B.1, Vorobeva I.G.2 2020. Spiders (Aranei) of the Arctic Island Sibiryakova, Kara Sea, Russia // Arthropoda Selecta. Vol.29. No.1: 141–150 [in English].

1 A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prospekt 33, Moscow 119071, Russia. E-mails: tanasevitch@gmail.com ; lrybalov52@mail.ru

2 Mari State University, Yoshkar-Ola, Lenina Sq. 1. E-mail: vigir@mail.ru

doi: 10.15298/arthsel.29.1.13

ABSTRACT. The Sibiryakova Island was found to be inhabited by 13 spider species of a single family Linyphiidae. In the composition of zoogeographic elements, the island fauna can be characterized as Siberian and consisting mostly of species with Siberian and Siberian-Nearctic ranges. In the composition of zonal fractions, the fauna is arctic and represented mainly by pure arctic components (11 species), with a small proportion of polyzonal species (2). Hypoarctic and boreal elements are absent. The study concerned the fauna and inhabitants of seven different types of vegetative communities: zonal (3) and intrazonal (4). The zonal (most pessimal) community — the moss-lichen polygonal tundra — is characterized, as compared to other areas, by the least number of species found (4) and by the least abundance of their populations (the exception is Halorates spetsbergensis (Thorell, 1872)). The vast majority of the fauna (10 species) and population is concentrated in the most wet intrazonal biotopes –– the moss-cotton grass polygonal tundra. Three species, Erigone psychrophila Thorell, 1872, H. spetsbergensis and Mecynargus tundricola Eskov, 1988, explore the whole range of biotopes, both zonal and intrazonal, though the highest dynamic density/activity is seen only in the latter ones. It was confirmed that the spider fauna in wet intrazonal biotopes is considerably richer and their inhabitants are more abundant and represented by a wider range of latitudinal fractions than in other kinds of vegetative communities of the arctic tundras. The dynamic density/activity of spiders is more than twice in intrazonal communities as compared to zonal biotopes. The pitfall traps are responsible for all the 13 island spider species found, the soil samples (40) found only 7 species. The density of spider population comprised from 10 specimens/sq. m. in swampy moss-lichen tundra to 46 specimens/sq. m. in moss-lichen polygonal one. Spiders are the dominating group of the soil macrofauna of arctic tundras. Based on the results of the pitfall trap catching, their proportion in the collection of land invertebrates comprised 60–91% in early July and 10–49% in the second part of July. Spiders comprise 27–63% of the macrofauna in the soil samples. Each of the 13 spider species of the Sibiryakova Island is characterized by distribution between the vegetation types, the range and belonging to the zonal fraction are indicated.

KEY WORDS: Russian Arctic, tundra, chorology, check-list, pitfall trapping, soil sampling.

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