| Abstract [eng] |
Lithuania has lost about two thirds of its total peatland area during the 20th century. Due to the drainage and mineralization of peat layer disturbed peatlands produce huge amounts of green house gasses. Large-scale land reclamation works were implemented in Nemunas delta region, where object of this study – Aukštumala raised bog is located. The aim of the study was to assess the state of raised bog plant communities and hydrological regime in the Aukštumala Telmological Reserve, and to study the potential of restoration of plant communities in the parts of Aukštumala raised bog, degraded by drainage and the fire, and in the cutover peatland. Specifically, we aimed to assess effectiveness of two different means of hydrological regime restoration: (i) bog isolation from peat harvesting fields using polyethylene membrane and “peat lock” system, and (ii) blocking of ditches using peat dams. In order to restore cutover part of Aukštumala peatland, fragments of typical raised bog vegetation were spread in experimental field. Aiming to restore hydrological regime favourable to natural raised bog plant communities, mean water table depth during vegetation season should be upheld above -30 cm. Polyethylene membrane, due to significantly higher mean water table depth is regarded as rather effective means to restore hydrological regime that creates unfavourable conditions for tree growth. Whereas, efficiency of “peat lock” was only observed on seasonal water level fluctuations. Although in the first year, 93% of the planted donor fragments of raised bog vegetation have recovered successfully at the experimental site of cutover peatland, the further formation of Sphagnum cover stopped due to extremely dry subsequent years. The processes may only be re-established if favourable hydrological conditions are ensured by effective regulation measures. |
