RECIPE

Peatland ecosystems possess a unique biodiversity, which may be threatened by commercial exploitation. At the same time, in many areas of central and northern Europe, peat utilization has been, and continues to be, a source of a valuable raw commodity and of income for rural communities. The "wise use of mires and peatlands" recognizes the validity of both of these viewpoints and seeks ways of resolving potential conflicts. RECIPE is designed to provide information to assist both conservationists and managers of peat extraction with options to restore peat accumulation and carbon sequestration in peatland that has either been abandoned or designated for restoration.

The approach will be to identify combinations of water table, vegetation, microbiology and chemistry favorable to the reestablishment of peatland biodiversity and long term regeneration. These will be made in the context of current management practices and taking account of both feasibility and the socio-economic benefits. Emphasis will be placed on understanding the relationship between the development of microbial diversity and the processes governing C cycling. Studies will be made of a range of regenerating peatlands as well as detailed regeneration experiments at specific sites. RECIPE will provide guidelines for sustainable management that will either reconcile continued peat use with the maintenance of biodiversity or aid the regeneration and biodiversity value of worked-out peatlands.

Major project outcomes:

• The microbial community in general has been shown to be broadly determined by "site" though there is also a response to "methane efflux" and "time since cutting", e.g. there is an increase in ascomycete prevalence amongst the fungi, an increase in nematodes and a decrease in diatoms as regeneration proceeds. Both the bacterial community and bacterial activity respond to vegetation changes. Archeal populations, and specifically those responsible for methanogenesis, are lower where plants have established in comparison to bare peat. Interestingly, these populations are more prevalent in the more northerly sites, within Scotland and Finland. Microbial processes and biodiversity indicators show significant responses to vegetation development and have the potential to track the progress of peatland recovery following commercial exploitation.
• Carbon substrate utilization profiles within the microbial population also reflect "site" differences though there can be unexpected overlaps, e.g. Le Russey, France, and Aitoneva, Finland, show a similar pattern. Microbial biomass C and N and, to a lesser extent, the C turnover rate within the microbial biomass all showed a positive response to regeneration stage and have potential as indicators of regeneration but CH 4 /CO 2 ratios were not useful. C from surface decomposing litter ( 13 C labelled) was found in lower peat profiles and to specifically label eubacterial, fungal and protozoan populations.
• Studies on testate amoebae (indicators of peatland regeneration) have made progress in understanding the taxonomy of two major groups. Diversity measurements using 18S rRNA have advanced to the point where it is now possible to design FISH (Fluorescent In Situ Hybridization) probes that can then be used for rapid identification.
• Changes in vegetation and in the microbial community are also reflected in the organic matter (OM) quality of the underlying peat. Cellulose and hemicellulose have been shown to be indicative of fresh plant material inputs while the sugars fucose and ribose indicate microbial synthesis. Differences are evident between "old" and "new" peat: "old" humified peat shows distinctive properties characteristic of an intensive degradation of OM such as large amounts of amorphous OM and mucilage; high compaction and lower C/N ratios while indicators of the new regenerating peat show microremains dominated by preserved tissues, low compaction and higher C/N ratios. Close relationships have been demonstrated between the OM chemistry and the FTIR (Fourier-Transform InfraRed) spectra of peat; both show significant effects of depth and age of the peat.
• Detailed studies over two growing seasons on carbon exchange within regenerating peatlands can now be modelled. Though the degree of modelling varies with site, early indications are that regenerating peatland can revert to being an active carbon sink, in contrast to the source that bare peatlands represent. This may take up to ten years though in some cases a sink may be achieved in as few as five years, depending upon site conditions. A twenty year old site showed good C sink characteristics. Results indicate that net carbon sequestration may begin by pioneering peatland sedge species already before Sphagnum moss colonization and that colonization by sedges accelerates the initiation of net carbon sequestration. Species composition affects the carbon gain. Ancillary determinations of d 13 C have given vital clues as to the source of respired carbon dioxide during the regeneration process. Though vegetative cover is a primary aim of peatland restoration, recovery of the carbon cycle such that such peatlands become a net sink may take longer to develop, probably within 5-10 years.
• A socio-economic evaluation of peatlands in each of the participant countries reveals that peat extraction as a commercial entity is only significant in Finland and Germany. Utilization in Scotland and France, though locally important, is relatively minor while no extraction occurs within Switzerland. At the same time a high value is put on peatlands as a natural ecosystem and this is being increasingly recognised within each member state. Attitudes and values placed on peatlands and their commercial exploitation vary considerably across the European Union.

Further information:

Additional information can be obtained by contacting Dr Steve Chapman (coordinator):