Fens - Habitat Action Plan

Ref 1/H4 Habitat Action Plan 4
Plan Author: English Nature
Plan Co-ordinator: English Nature
Final Draft 31 December 1998
Revised Final Draft 21 September 2005
 

Action Plan Summary

Current Status

National Status

  • The UK is thought to host a large proportion of fen surviving in Europe. As in other parts of Europe, fen vegetation has declined dramatically in the past century. Fens are peatlands, which receive water and nutrients from rock, soil and ground water, as well as from rainfall: they are minerotrophic. Two types of fen can broadly be distinguished: topogenous and soligenous. Topogenous fens are those where water movements in the peat or soil are generally vertical, these include floodplain fens and basin fens. Soligenous fens, where the water movements are predominantly lateral, include mires associated with valley fens, springs and flushes. Fens can be described as 'poor-fen' or 'rich-fen'. Poor-fen, where the water is derived from base-poor rocks occurs in the lowlands with heathland. Rich-fens are fed by mineral-enriched calcareous waters.

Norfolk Status

  • Norfolk is particularly rich in fen habitats, supporting a large proportion of the UK total for some types. The Broads natural area possesses some 5,000 ha of rich-fen habitat, mostly of the floodplain type, with some examples of valley fen. Rich-fen is also associated with pingo sites such as Thompson Common, East Walton and Adcock's Common and Foulden Common. Elsewhere, numerous rich-fens of the valley head type are found associated with the county's rivers. In north-west Norfolk, some 350 ha of poor-fen is found primarily associated with Roydon Common and Dersingham Bog. Table 1 below lists Norfolk SSSIs that support an important fen component. Many other fen sites are recognised as County Wildlife Sites.
  • Fen habitats support a particularly diverse array of plants and animals, including:
  • Over 250 plant species, some of which cannot be found anywhere else in lowland Britain, such as the fen orchid;
  • Birds, such as bittern, bearded tit and marsh harrier;
  • Mammals, such as water vole, otter, harvest mouse, vole and water shrew;
  • Butterflies such as the swallowtail (Papilio machaon). The British race of this species (britannicus) occurs only on fens in the Norfolk Broads; 
  • Moths, including rare species such as reed leopard and fen's wainscot;
  • Numerous species of dragonflies and damselflies, such as the scarce chaser (Libellula fulva) and the Norfolk hawker (Aeshna isosceles);
  • Many other invertebrates, including BAP species such as the reed beetle (Donacia aquatica), a ground beetle (Badister peltatus), the lesser water measurer (Hydrometra gracilenta), a weevil (Melanopium minimum), and the diving beetle (Bidessus unistriatus).

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Current factors affecting the habitat in Norfolk

  • Fens are dynamic, semi-natural systems and in general, management is needed to maintain open fen communities and their associated species richness. Without appropriate management and water supply, natural processes will lead to scrub and woodland forming. Current factors affecting this habitat type include:
  • Land drainage and land use, local and within catchments, affects water quality and quantity within and around fen sites.
  • Changes in hydrology of floodplain fens, where they have become isolated from the river water which irrigated the fen.
  • Excessive water abstraction from aquifers and surface sources reduces spring flows and lowers water tables. Abstraction affects the natural balance between the differing water qualities of ground and surface water.
  • Lack of appropriate management remains an issue, both the restoration of past neglect and maintaining systems of sustainable, ongoing management post-restoration.
  • Fens, particularly those of the valley type, are susceptible to run off of poor quality water, and drainage from agricultural land and afforestation within the catchment.
  • Enrichment or hyper-trophication resulting in changing plant communities.

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Current Action in Norfolk

A large proportion of fen habitat in Norfolk has been designated SSSI, with much of this also candidate SAC and Ramsar site. Many fens are managed by conservation bodies, some of which are also managed as NNRs. 

  1. English Nature and the Broads Authority have produced a Fen Audit, identifying management possibilities and constraints for each fen site. This supplements the Fen Management Strategy for the Broads Natural Area. Restoration aims will be agreed with landowners. 
  2. All conservation bodies and many landowners are undertaking management works to restore favourable conditions on SSSI fen sites.
  3. The Broads Authority leads a partnership project co-ordinating mechanised fen harvesting equipment. Also experimental grazing of fen sites is being progressed in the Broads. 
  4. The new Environmental Stewardship scheme, to replace ESAs, has the potential to provide appropriate levels of funding through the Higher Level Scheme to support sustainable management of fen habitats. Conservation staff from English Nature, Broads Authority, Norfolk Wildlife Trust and Farming and Wildlife Advisory Group (FWAG) provide management advice, both to landowners and DEFRA. 
  5. A programme of fen research and monitoring is to be developed as an outcome from the Supplement to the Fen Management Stratgey, which incorporates the Broads Fen Audit. All conservation bodies are involved in monitoring fen sites.
  6. The Environment Agency has embarked on an extensive water level monitoring project for a number of Norfolk fen sites. Many fens are subject to Water Level Management Plans prepared by operating authorities. English Nature and the Broads Authority have commissioned research into the hydrological functioning of fen sites.
  7. Water Companies have undertaken improvements to sewage treatment works, thereby improving the quality of water in the Broads. Further water quality improvement projects will be undertaken by Water Companies under AMP4. 
  8. Under AMP4, further investigations for water quality will be undertaken by water companies.
  9. Restoration and management of Cladium rich fen by the Reed and Sedge Cutters' Association.

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Action Plan Objectives and Targets

National

  • Identify fen sites in critical need of, and initiate rehabilitation by 2005. All rich fen and other sites with rare communities should be considered.
  • Ensure appropriate water quality and water quantity for the continued existence of all SSSI fens by 2008.

Norfolk

  • Identify Norfolk fen sites in critical need of rehabilitation by 2005, and initiate restoration by 2010.
  • Ensure appropriate water quality and water quantity for the continued existence of all Norfolk SSSI fens by 2010.
  • Complete restoration of SSSI fen sites by 2010
  • Identify key non-SSSI fens for restoration by 2005, and initiate restoration plans.

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