Early summer aspect of the population of ground–dwelling spiders (aranei), harvestmen (opiliones) and ground beetles (coleoptera, carabidae) in pinus sibirica forests of Shorsky national park

Abstract

The early summer structure of the communities of ground-dwelling spiders, harvestmen and carabids in Pinus sibirica forests of the Shorsky National Park has been studied for five years. The community was found to consist of 39 spider, 5 harvestman and 12 carabid species. Among spiders,small-sized litter-dwelling web-producing spiders (Linyphiidae) predominated, accounting for over 70 % of collected specimens. The community of wolfspiders (Lycosidae) was small and taxonomically poor, their dynamic density in the study area being rather low and unstable. Although spider species outnumbered the other studied groups, their population was generally scant and unstable. The composition of spider dominants varied among years, their dynamic densities and shares were unstable even in regularly collected species. Pairwise comparisons of the early summer structure of spider communities in different years did not always show statistically significant differences. Early summer communities of harvestmen in Pinus sibirica forests were predominated by juveniles of Mitopus morio (Fabricius, 1779), with first emergences of newly hatched Oligolophus tridens nymphs (C. L. Koch, 1836). The most abundant among eurychronic species was Sabacon sergeidedicatum Martens, 1989. In the early summer beetle community, the family Carabidae was the dominant group of ground-dwelling arthropods. The dominants complex was stable, and included Carabus aeruginosus Fischer von Waldheim, 1822, Pterostichus monticoloides Shilenkov, 1995, P. oblongopunctatus (Fabricius, 1787), and P. virescens (Gebler, 1833). Their population structure did not vary significantly among years. The Sorensen similarity indexes for the species composition of carabid communities in among-year pairwise comparisons were oftener higher than those for spiders.