An Influence Of The Steppe Fire On Fauna And Spiders Population Structure (aranei, Arachnida) In «kamennye Mogyly» Reserve (volodarskiy Region, Donetskaya Oblast)

Abstract

E. V. Prokopenko, E. Yu. Savchenko

The problem of human-caused fires in the steppe ecosystem is complex: it seems wrong to think of them only as a negative or as a very positive thing. It should be noted that, despite the frequent summer fires in reserved areas of Ukrainian grass-fescue-feather grass steppes, studies on the pyrogenic effects on the fauna of Aranei, are extremely few. The aim of our study was to investigate the taxonomic composition and structure of the population of spiders in the burned site of petrophytic steppe in the "Kamennye Mogily" reserve, to compare the main structural characteristics of communities with those on the control plots, to identify indicators most sensitive to the pyrogenic factor. As the result of our research 75 species of spiders belonging to 18 families were collected. The representatives of families Gnaphosidae (22,4% of species), Linyphiidae (18,4%), Lycosidae (14,5%) and Salticidae (10,5%) formed the basis of the fauna of Aranei. The impact of fire on the fauna and the population of spiders showed in a slight decrease in quantity and increase in the number of species on the burned-out area. Throughout the study there were noted 63% of species at the control sites and about 87% of the species caught in the fumes. Several species are found at the burned areas only and not recorded in the control (S. albomaculata, M. peusi, M. prominulus, A. cursor, A. schmidti, A. trabalis, P. pullatus, E. frontalis, P. obsoleta). Such species as A. sulzeri and P. variana prefer only unburned steppe. In the studied biotopes vary the composition of the dominant species: A. pulverulenta (virgin steppe) and A. solitaria, T. ruricola, E. kollari (fumes). The sharp difference was noted in the relative quantity of the family Eresidae, the most numerous in the burned areas. During recovery of vegetation in the year following a fire the quantity of spiders in the fumes remains lower than in controls and the difference in species richness disappears. The effect of enrichment of the fauna of Aranei leveled, and the spiders’ quantity is still lower than in unburned steppe. The difference in the relative quantity of the main families in the burnt site and in control, which took place in the year of the fire, is significantly reduced (except Eresidae).

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