Özet:

The article considers the species composition of the Dothideomycetes and its structural characteristics in conditions of anthropogenically transformed ecosystems of the steppe zone of Ukraine. The materials of the work were the original mycological collection carried out as part of the mycological survey of this territory during 2008–2016, as well as the materials of the herbarium of the Institute of Botany named after M. Kholodny of the National Academy of Sciences of Ukraine. Herbarium collection and identification of the samples were performed in accordance with the generally accepted methods of cameral processing of xylotrophic, herbotrophic and coprothrophic micromycetes. To establish the taxonomic affiliation of species, the method of light microscopy was applied. As a result of our research, the species diversity of ascolocular fungi (Dothideomycetes) has been established in the anthropogenically transformed ecosystems of the steppe zone of Ukraine, which includes 156 species from 43 genera 19 families 5 orders and groups of taxa of Incertae sedis of the subclasses Dothideomycetidae and Pleosporomycetidae. The characteristic features of the taxonomic structure of the investigated mycobiota are the predominance of representatives of the order of Pleosporales, the families Cucurbitariaceae and Mycosphaerellaceae, the genera Cucurbitaria and Mycosphaerella. In the ecological structure of mycobiota in anthropogenically transformed ecosystems saprotrophic and xylotrophic species dominated. The ascolocular fungi species are form consortium connections with 178 species of vascular plants from 112 genera of 51 families, with the largest number of micromycetes (65 species) noted on plants of the Rosaceae. An analysis of the abundance of species in anthropogenically transformed ecosystems of the investigated area showed that 47% of the species are randomly distributed. Widespread species are Dothidea sorbi (Wahlenb.) Sacc., Cucurbitaria caraganae P. Karst., C. amorphae (Wallr.) Fuckel, Botryosphaeria dothidea (Moug.) Ces. & De Not., Otthia spiraeae (Fuckel) Fuckel. In the anthropogenically transformed ecosystems of the steppe zone of Ukraine, in comparison with natural ecosystems, the proportion of species from the genera Cucurbitaria and Mycosphaerella increases quantitatively, and the proportion of Leptosphaeria and Pleospora species decreases. An increase in the proportion of hemibiotrophic species in the ecological structure can be considered a characteristic feature of anthropogenic influence on mycobiota . Comparative analysis of quantitative and qualitative indicators of the mycobiota structure combined with spatial and temporal changes of these indicators can serve as an instrument for indicating its anthropogenic transformation. It would be promising to conduct further research on changes in the species structure of micromycetes exposed to various types of anthropogenic impact in terrestrial ecosystems of the steppe zone of Ukraine.

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