Plant communities and peat deposit peculiarities of Ravdukorbi floodplain mire

The Ravdukorbi mire, located along the creek of the same name, is adjacent to Vagatozero, the reach on the Shuya river. The mire is influenced by the regular flooding during spring floods due to the hydrological regime of the lake and the flat nature of the surrounding terrain. The studies conducted in 2013 revealed zonation patterns in the organization of vegetation dependent on the distance from the creek. The following sequence in community changes is described: open sedge-Comarum and willow-Comarum communities; herb-dwarf-shrub-sphagnum community with sparse birch standa; birch swamp; pine herb-sphagnum mire; pine-dwarf-shrub-sphagnum mesooligotrophic community. The DCA-ordination of the plots confirmed the main role of the floodplain-alluvial gradient in the organization of mire vegetation. The average peat deposit depth is 100 cm; the largest depth of 135 cm is achieved on the mesooligotrophic site. The peats of eutrophic type are highly decomposed with mineral sediments. The lake impact on the mire is traced during the whole history of its formation; most of the deposits correspond to the present community composition. The vegetation of the sites, which is slightly or not influenced by the flood water transforms to oligotrophic stage of development.