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The litter in a forest ecosystem acts as a trophic substrate, and at the same time it is the environment for litter invertebrates. But despite this fact, there has been very little research conducted on the influence of litter thickness on the structure of litter macrofauna. The litter of steppe forests contains most types of integrated communities of forest ecosystems. This means that its thickness cannot avoid playing a significant role in the functioning of the ecosystem. Following to the standard methodologies, Invertebrates were collected using pit-fall traps in deciduous forests of Nikolaev, Zaporizhzhya, Dnipropetrovsk, Donetsk and Kharkiv oblasts, which are characterized by different types of geomorphological profile, different moisture conditions, soil salinity, tree crown and herbaceous vegetation density, soil texture and other factors. The total number of macrofauna increases in conditions where litter thickness exceeds40 mmin comparison with forest ecosystems with fragmented and average capacity litter. The number of litter macrofauna species also increases from 11–23 to 38 species on average when litter thickness increases to more than40 mm. The Shannon and Pielou diversity indexes show no definite tendencies to change in relation to changing degrees of litter thickness. At sites of greater thickness of the litter layer, the corresponding increase in the absolute number of litter mesofauna invertebrates is mostly due to saprophages, and the increase the number of species – due to zoophages. The optimum structure of domination was observed at sites with maximum thickness of litter. The proportion of large species shows no statistically significant change in relation to variations in litter thickness. The qualitative compound of the fauna at sites with thick litter changes mainly due to an increase in the number of Carabidae species.

An analysis of litter invertebrate community structure of 141 pine forest ecosystems in the steppe zone of Ukraine in five moisture gradations has been carried out. The absolute number of macrofauna individuals in the pine forests of the steppe zone of Ukraine is on average 5 times lower than in the corresponding moisture conditions of deciduous forests. The average number of species and the Shannon-Weaver diversity index increases from mesoxerophilous to hygromesophilous conditions. The relative number of saprophages increases when the degree of moisture increases from mesoxerophilous through to mesohygrophilous conditions. Zoophages do not change their number with optimisation of moisture conditions; only the number of their species increases. The relative number of polyphages decreases as the soil humidity increases. It is possible to observe significant deviations in the size structure of pine forest macrofauna in comparison with that of steppe zone deciduous forests: the share of 4-7 mm size group increases and the number of individuals with >20 mm body length decreases in most moisture gradations. In pine forest litter, Formicidae occupy the first place among dominants, in hygromesophilous and mesohygrophilous forest types Porcellionidae make up more than a quarter of macrofauna, while Lycosidae and Carabidae dominate in all moisture gradations. The results of the studies allow us to assess the importance of pine forests in the steppe zone as low for preserving biological diversity of litter macrofauna. [ABSTRACT FROM AUTHOR]