Abstract. Natural peatlands are important carbon sinks and sources of methane (CH 4 ). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N 2 O). Rewetting of peatlands thus potentially implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration are scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated sites of a bog ecosystem 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO 2 ) ranging between 0.6 ± 1.43 t CO 2 ha −2 yr −1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO 2 ha −2 yr −1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of CO 2 , CH 4 and N 2 O, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO 2 -eq ha −1 yr −1 and were dominated by large emissions of CH 4 (22-51 t CO 2 -eq ha −1 yr −1 ), with highest rates found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH 4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in the water table, we assume that the high CH 4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of purple moor grass and the plant-mediated transport through its tissues. In addition, as a result of the land use history, mixed soil material due to peat extraction and refilling can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH 4 emissions due to rewetting as described in the literature is not inevitably limited to a shortterm period.

Abstract. Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration is scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated bog sites 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha-2 yr-1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha-2 yr-1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of the three greenhouse gases, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha-1 yr-1 and were dominated by large emissions of CH4 (22 up to 51 t CO2-eq ha-1 yr-1), while highest rates were found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in water table, we conclude that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of this grass species and the plant-mediated transport through its tissues. In addition, as a result of the land use history, the mixed soil material can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not limited to a short-term period.

reden heißt, es ernst zu meinen. Von Revolution reden heißt, mit dem Pazifismus aufgehört haben, mit der Askese des Immer-schon-dagegen-gewesen-seins mit der Ausrede, Es-zwischen-den Zeilen-zum Ausdruck-gebracht-zu-haben, mit der schönen Trauer: Was-hätte-man-denn-sonst-tun-können? Ein tabubrechendes Stichwort, insofern es Gewalt rechtfertigt, anstelle von Weltanschauung den Anspruch der Weltveränderung setzt, von Beschaulichkeit Verbindlichkeit und den Weg aus dem schlechten Gewissen in die Resignation abschneidet." (Meinhof 1968: 208)