Patterns in the horizontal structure of litter invertebrate communities in windbreak plantations in the steppe zone of the Ukraine

摘要

The article analyses the patterns in the horizontal structure of litter invertebrate communities in windbreak plantations in the Steppe zone of the Ukraine. The number of invertebrate species shows statistically insignificant changes depending on theextent of the litter horizon development. With an increase in litter mass from 300 to 900 g/m2 the number of invertebrate species increases. An increase in the total number of macrofauna is observed in areas having a minimum and maximum thickness of thelitter layer. Maximum values in the Shannon diversity index were observed in areas with sparse litter (50-150 g/m2). An observed increase in the variety of macrofauna species were seen where there was sparse grass cover in windbreak planted areas. The total number of litter invertebrate individuals related to the percentage of projective cover of herbaceous plants shows a significant increase in plots with 20-28% cover, though this factor does not affect the number of Aranei, Carabidae, and Staphylinidae. There is a decrease in the number of litter invertebrate species in areas with higher numbers of Lasius platythorax Seifert, 1991, while there is an insignificant change in the overall numbers of macrofauna. The abundance oiMyrmica scabrinodis Nylander, 1846 does not show a significant influence on the number of litter macrofauna species. The minimum values of the Shannon biodiversity index for macrofauna were registered in plots with maximum numbers of M. scabrinodis. With an increase in the abundance of ants, the abundance of litter saprophages and phytophages decreases. There are also significant changes in the dominance structure of other taxonomic groups. Biotic factors have greater significance for the horizontal structure of litter macrofaunaof steppe plantations than abiotic factors.