Recovery of methanogenic community and its activity in long-term drained peatlands after their rewetting. Methanogenic community and its activity in peatlands

We investigated the effect of long-term drainage and hydrological restoration on methanogenic abundance, community composition and activity (CH4 production potential) in bog and spruce swamp forests. Additionally, the substrate limitation of methanogens was tested with a focus on original peatland plant species and their spreading in restored sites. Therefore, natural substrates made from dried milled Sphagnum and sedges were added to peat samples.Long-term drainage strongly reduced abundance and diversity of the methanogenic community in both peatland types. In restored sites, methanogenic abundance and community composition reached almost pristine like state, however their CH4 production remained as low as in drained sites. Substrate addition confirmed the substrate limitation of methanogens due to strongly decomposed peat and slow spreading of original peatland vegetation. The addition of natural substrates supported methanogenesis close to pristine-like level.