Coastal and Floodplain Grazing Marsh - Habitat Action Plan

Ref 1/H7 Habitat Action Plan 7
Plan Author: English Nature
Plan Co-ordinator: English Nature
Final Draft 31 December 1998
Revised Final Draft December 2005

Action Plan Summary

Current Status

National Status

  • Grazing marsh is defined as periodically inundated pasture, or meadow with ditches which maintain the water level, containing standing brackish or fresh water. The ditches are often especially rich in plants and invertebrates. Grazing marshes are also of importance for both breeding and wintering bird populations. The exact extent of grazing marsh in the UK is not known but it is possible that there may be a total of 300,000 ha. England holds the largest proportion with an estimate in 1994 of 200,000 ha. However only a small proportion of this grassland is semi-natural supporting high diversity of native plant species (5,000 ha in England, an estimated 10,000 ha in the UK).

Norfolk Status

  • Grazing marsh is an extensive habitat within Norfolk, estimated to cover some 29,500 hectares. Individual blocks vary greatly in size, from 10 ha rising to 2,642 ha for Halvergate Marshes. Much of the resource is found in the Broads Natural Area, the North Norfolk Coast, and to a lesser degree the Wensum and Waveney valleys and the Wash hinterland.

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Current factors causing loss or decline in Norfolk

  • Losses in the whole UK have been significant in the last 60 years. Losses of grazing marsh from the early 1930s to the mid-1980s include 37% in the Broads. Some of the last remaining unimproved grasslands are highly sensitive to increased nutrient loadings. Unless conservation measures to retain this habitat type are in place, with particular emphasis on the maintenance of water levels, flood regimes and appropriate grazing or cutting, most sites will deteriorate. The ESA Scheme (now superseded by Environmental Stewardship) has reversed this trend in the Broads.

The primary threats to grazing marsh are of both a widespread and localised type:

Widespread factors include:

  • Drainage and water abstraction.
  • Eutrophication, diffuse and point source.
  • Pollution of ground and surface waters, including pesticides.
  • Changes to more brackish or coastal habitats due to sea level rise (this may be beneficial overall to other habitats).

Localised effects arise from:

  • Implementation of flood management works (may be beneficial to other habitats, such as rond and open water in dykes).
  • Inappropriate standard of flood defence (both too high and too low).
  • Lack of functioning of floodplain through river management, such as canalisation and floodbanks.
  • Aggregate extraction.

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Current Action in Norfolk

  • A large proportion of the grazing marsh resource is protected by SSSI designation. The SSSIs within the Broads are also a recognised Special Protection Area and Ramsar site and candidate Special Area of Conservation. Those on the North Norfolk Coast are recognised as a Special Protection Area and a Ramsar site.
  • The floodplains of the rivers Yare, Wensum, Waveney, Bure, Ant, Thurne, Tas and Tud are all within the Broads ESA. In addition, parts of the Wissey, Thet and Little Ouse lie within the Brecks ESA. The ESA scheme has been superseded by Environmental Stewardship, but ESA agreements will remain place until the five-year break clause is reached.
  • Much of the grazing marsh within the North Norfolk Coast AONB is managed as National Nature Reserve, nature reserve, or under English Nature agreement or the Countryside Stewardship Scheme.
  • The Broads is a nationally recognised wetland, forming one of the family of National Parks.
  • Conservation organisations have provided much management advice via landowner contact, demonstration events and publicity material.
  • Much of the grazing marsh area is subject to, or will soon be subject to Water Level Management Plans prepared by Operating Authorities.
  • The Environment Agency and BESL, in developing the Broads Flood Alleviation Strategy, are undertaking flood management schemes to give flood defence assurance for land and property in accordance with that in 1995.
  • Conservation organisations undertake extensive survey and monitoring of grazing marsh habitat.

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Action Plan Objectives and Targets

National

  • Maintain the existing habitat extent (300,000 ha) and quality. 
  • Rehabilitate 10,000 ha of grazing marsh habitat which has become too dry, or is intensively managed, by the year 2000. This would comprise 5,000 ha already targeted in ESAs, with an additional 5,000 ha.
  • Begin creating 2,500 ha of grazing marsh from arable land in targeted areas, in addition to that which will be achieved by existing ESA schemes, with the aim of completing as much as possible by the year 2000

Norfolk

  • Maintain the existing habitat extent (29,500 ha) and its quality.
  • Rehabilitate 2,950ha (10% of the total resource in Norfolk) of grazing marsh habitat in intensive management by 2010.
  • Aim to create 350 ha of grazing marsh from arable land on the North Norfolk Coast by 2010. This target is in addition to any habitat creation that may be necessary as a result of changes in coastal management.

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