Ecological restoration and soil biology

The Chreienriet is a former moorland area that is still recognisable as a wetland on historical maps. The bog has been drained and used as agricultural land for many years. The peat body therefore degraded, leading to subsidence. Over time, the old drainage systems increasingly failed and the area became wetter again - which, together with the unstable turf, made cultivation increasingly difficult. Today, the area offers good conditions for restoring its natural functions. As part of the project, the southern part of the Chreienriet will therefore be renaturalised and returned to a near-natural state.

The institute of nature conservation is carrying out ecological upgrading of the former reedbed. The heavily eroded peat on the surface has been removed and the water balance has been re-regulated in order to restore the wetland. The Cantonal Soil Monitoring Centre (KaBo) has established a monitoring site in this area in order to document the long-term soil development following the implementation of the conservation measure.

The draining of the former moor has greatly changed the soil conditions, and significant amounts of CO₂ have been emitted as a result of peat extraction. The rewetting of the site is now changing the soil environment again: oxygen-limiting conditions are created in accordance with the site's natural characteristics. This can promote the growth of methane-producing microorganisms (archaea), potentially leading to increased methane emissions. At the same time, restoration measures can minimize peat degradation and thereby reduce CO₂ release, while also increasing the amount of readily available carbon that microorganisms can use more efficiently. If this leads to the formation of stable biomass, less carbon is released as CO₂ and is instead stored in the soil over the long term. Both processes, methane production and carbon sequestration, must therefore be considered together in order to assess the climate impact of rewetting.

In order to better understand the effects of rewetting on soil biology and soil functions, various laboratory analyses are being carried out as part of the project before the intervention and after various stages of peatland regeneration. In addition to some soil parameters such as carbon content and carbon stock as well as C:N ratio, the change/development of the microbial communities will be recorded. For this purpose, the nucleic acids (DNA) are extracted from the soil and the bacterial and fungal diversity and composition of the microbial communities are determined in our laboratories using specific genetic markers by means of sequencing. In addition, we search the soil for specific microorganisms that are responsible for the formation of methane and nitrous oxide. For this purpose, functional genes of these microbes are detected and quantified using modern molecular biological methods (quantitative PCR). In this way, we determine how strongly these functionally important microorganisms are represented in the soil and what influence peatland regeneration has on soil functions. These findings help to better categorise the ecological effects of rewetting.