Restoration of Drained Mires (Å umava National Park, Czech Republic)

About 70% of mires in the Šumava Mountains have been influenced by past drainage for variously forestry, agriculture and peat extraction. Since 1999, a comprehensive “Mire Restoration Programme” has been implemented in the Šumava National Park, primarily focused on the disturbed hydrology. The main restoration technique used has been the blocking of drainage ditches. Selected drained and intact mires were also monitored with the aim: (i) to characterise the degradation changes induced by the disturbed hydrology; and (ii) to evaluate the success of restoration. Water-table fluctuations, hydrochemistry of groundwater, surface-water outflow, amount of precipitation and the vegetation on permanent plots have been monitored. Pre-restoration monitoring data had shown differences between drained and intact sites. On drained bog sites, water tables were maintained at lower levels and exhibited higher fluctuations compared to intact sites. Expansion of the more competitive grasses and trees towards the bog expanse was recorded on drained bogs as well as expansion of dwarf shrub vegetation and reduction of Trichophorum lawns and hollow vegetation. Preliminary results from the initial post-restoration phase have shown a rise in the water table, stabilisation of the hydrological regime and some changes in hydrochemistry at restored sites.