Assessment of the diversity of vascular plants in phytocenoses with a share of Quercus mongolica on the territory of Relic Oaks State Reserve

In this paper, we assess the diversity of vascular plants in phytocenoses with Quercus mongolica (family Fagaceae) on the territory of the Relic Oaks State Reserve (Eastern Siberia, Transbaikal region), where Q. mongolica is located at the northwestern boundary of the areal. The descriptions of phytocenoses have been processed in the PAST3 application. The similarity of species composition has been determined using the Jaccard index. The resulting tree diagram shows two groups of descriptions at a similarity level of 0.14-0.15. The first group includes the descriptions of mixed forest quadrats, in which Q. mongolica is a co-edificator. The second group of descriptions presents the communities where Q. mongolica is the only species in the tree layer. The analysis of the tree diagram shows the dependence of species richness within the phytocenoses on the surface patterns and edaphoclimatic conditions. The phytocenoses located on steep southern slopes show less diversity