DEFRA Greenhouse Gas Emissions

The East Anglian Fens represent the largest, and most intensively modified area of lowland peat in the UK. This research project will quantify greenhouse gas fluxes from fenland under different land use to derive recommendations for land management and climate mitigation policies. It uses data collected by two eddy covariance flux towers and field measurements. The large areas under drainage and cultivation are undergoing severe and continuing peat carbon loss, leading to peat wastage across large areas. Small areas of ‘natural’ fen vegetation remain, while other areas have undergone re-wetting and (partial) restoration from intensive to extensive agricultural use.

As part of a long-term collaborative research programme with the NERC Centre for Ecology and Hydrology (CEH), called FENFLUX, we are monitoring carbon, energy and water exchanges between the land and the atmosphere at Wicken Fen Nature Reserve. It is the largest of only four surviving fragments of the Great Fen Basin of East Anglia remaining under natural tall fen vegetation. The fen has an exceptionally rich flora and fauna, is a SSSI and conserves habitat and rare species. The sedge is harvested regularly in a rotational cropping scheme every 3-4 years continuing the traditional low impact use. The site is under high water table management, although water table drops significantly in summer. Recently water supply has been improved with lode water to maintain the mineral water supply and soil chemistry.

Bakers Fen, also in the Wicken Fen Nature Reserve, is located close to the natural Sedge Fen. It was converted from intensive arable agriculture in 1998, by raising water tables during winter, and introducing extensive conservation grazing by Konics and Scottish Highland cattle. The site has a small elevation gradient supporting flooding of a larger area until late spring which creates a more naturally varied landscape. The vegetation is dominated by pasture grasses, with some patches of Juncus effusus. The monitoring station also records soil moisture and temperature at multiple locations as well as soil heat flux. Water level is regularly recorded at several dipwells, and monitoring continuously by four continuous water level recorders.