Is spontaneous regeneration of raised mire vegetation possible? A case study of the `Czarne Bagno' mire in the Bystrzyckie Hills,southern Poland

Research carried out at the `Czarne Bagno' raised mire in the Bystrzyckie Hills range of Poland's Sudety Mountains aimed to determine dynamic trends for the site's peatland vegetation. Present vegetation was therefore characterized. An analysis of plant macroremains from peat cores was used to reconstruct the identity of the past peat-forming plant communities. Several succession stages of vegetation from the time of origin of the peatland through to the present day were indicated on this basis. Ecological indicative values of plant species were also used to determine the palaeohydrological changes experienced. Stages of the development of the tree stand growing on the mire were established from dendrochronology series. Results obtained point to an interruption of the succession of primary vegetation on the peatland around 250 years ago, when today's sparse tree stand of rhaetic pine, Norway spruce and downy birch began to develop. Nevertheless, the last 50 years have brought a reversal of this developmental trend, with elements typical for raised mire returning and the tree stand in retreat. These phenomena seem to have coincided with the onset of peatland drainage, followed by a gradual overgrowing of drainage ditches and consequent re-raising of water level in the mire, respectively.