Transformation of Soils and Mire Community Reestablishment Potential in Disturbed Abandoned Peatland: A Case Study from the Kaliningrad Region, Russia

Degrading organic soils usually become a source of increased greenhouse gas emissions and fire frequency in disturbed peatlands. As a solution, the rewetting concept should consider not only the detailed hydrological characteristics of the peatland, but should also appraise the properties of the soils. Here, we provide the results of a detailed soil study carried out on an abandoned peatland in the Kaliningrad Region, Russia. The study aims to integrate data on soil properties, hydrology, and the degree of transformation of the current soil cover in terms of how this affects spontaneous revegetation and the potential for further mire community reestablishment. The paper contributes to a greater understanding of rehabilitation patterns of disturbed peatlands depending on the soil’s physical and hydrological properties in the humid climate of the southeastern Baltic region. The present-day soils of the peatland refer to two World Reference Base (WRB) groups: Gleisols and Histosols; the latter change successively from the periphery to the centre of the peatland as follows: Eutric/Sapric → Hemic → Dystric → Fibric. Most Histosols are characterised by hydrothermal degradation in the upper layers with patches of pyrogenic degradation. Some local inundated areas show environmental conditions favourable for Sphagnum growth and the formation of mire communities. We have identified six groups of sites with different ecological and time-span potentials for mire community restoration during the implementation of rewetting activities. The rewetting feasibility of the peatland’s sites does not coincide with the degree of transformation of their soil profile, but is rather determined by the hydrological regime.