Floodplain Grazing Marsh

Habitat Description

Floodplain grasslands in the UK are predominantly semi-natural or man-made habitats, strongly influenced by water management and by farming practices. They form important habitats for wildlife, perform a vital flood storage function and play a significant role in traditional farming systems. Winter floods bring nutrients to the grasslands and traditional farming systems recognised this benefit, with the productive sward in the meadows managed for hay production and cattle grazing.

Grazing marsh is defined as periodically inundated pasture, or meadow with ditches that maintain the water levels, containing standing fresh water. The ditches are especially rich in plants and invertebrates. Almost all areas are grazed and some are cut for hay or silage. Sites may contain seasonal water-filled hollows and permanent ponds with emergent swamp communities. In Northamptonshire it includes the following NVC communities:

   
  • MG9 Holcus lanatus Deschampsia cespitosa (Yorkshire fog Tufted hairgrass)
  • MG10 Holcus lanatus Juncus effusus (Yorkshire fog Soft rush)
  • MG11 Festuca rubra Agrostis stolonifera Potentilla ancerina (Red fescue Creeping bent Silverweed)
  • MG12 Festuca arundinacea (Tall fescue)
  • MG13 Agrostis stolonifera Alopecurus geniculatus (Creeping bent Marsh foxtail)
  • Inundation Grasslands MG9-13 grasslands

    Inundation grasslands occur on poorly structured clay soils that flood in winter and spring, but do not then readily drain. As such, plant species present have to contend with water-logging in early summer and then drought conditions as the soil gradually dries out. Example: Plumpton Pasture SSSI.

    Current UK Status and Trends

    Floodplain grazing marsh has declined significantly. In England and Wales the remaining wet grassland covers an area of approximately 220,000ha from a historical resource of 1.2 million ha. Losses over the last 60 years are typically 30-60% by area.

    Estimated Current Northants Resource

    15.25 ha of 'Wet Marsh' adjacent to rivers have been recorded in Local Wildlife Sites. 259 ha of floodplain grazing marsh, of all levels of quality, were reported in 2002.

    Progress Towards BAP Targets 2002-2007

    Negotiations are under way to create areas of floodplain grazing marsh in the Earls Barton West area, as part of a wider wetland mosaic, following proposed aggregate extraction. Since 2004, some areas of former arable or intensive grassland have been reverted to more natural floodplain grassland under the Environmental Stewardship Scheme.

    Lead Partner

    RSPB

    Main Issues and Threats

    • Agricultural intensification, leading to drainage and conversion to arable farmland;
    • Water abstraction.
    • River channel modifications (deepening, widening, and construction of flood defences) altering the frequency and duration of flooding.
    • Eutrophication of ditch systems and surface water features from diffuse pollution mainly from agricultural run off.

    General Strategy

    • Burrow down into the Green Infrastructure strategy on a field-by-field basis to identify the current resources and highest priorities for linkage by sympathetic management of degraded sites and establishment of new sites.
    • Sympathetic management and restoration of existing sites, funded primarily through the Environmental Stewardship Scheme (Advice can be provided by The Wildlife Trust, RNRP or FWAG).
    • Promote recreation opportunities targeted at key areas of the floodplain, to be delivered primarily by restoration of mineral sites where physical characteristics permit.

    Additional Information

    Poor condition BAP habitat: Hydrological regime in place but site inappropriately managed i.e. water levels too low, insufficient or no wet surface features or flooding, inappropriate sward condition, incorrect hedge height, excessive scrub cover.

    Example of relict habitat: Hydrological regime no longer in place but typical physical features of FPGM present e.g. ditches reflecting land that has previously and more recently been managed as wet grassland and also reflected in either the existing land use and / or botanical communities present e.g. intensively cultivated drained land.

    Habitat for new FPGM creation: Generally agricultural land with no typical physical features of FPGM present reflecting land that has not recently been managed as wet grassland and also reflected in either the existing land use and / or botanical communities present e.g. intensively cultivated drained land.

    Associated National Priority Species

    • Black-tailed godwit
    • Blood-vein (moth)
    • Eurasian curlew
    • Flat-sedge
    • Marsh stitchwort
    • Northern lapwing
    • Oblique carpet (moth)
    • Powdered-quaker (moth)
    • Pennyroyal
    • Shoulder-striped wainscot (moth)
    • Small square-spot (moth)
    • The crescent (moth)
    • The concolorous (moth)
    • Tubular water-dropwort
    Specific Management Required for Associated Species

    Species

    Northamptonshire Status

    Management Prescriptions

    Key Sites

    Flat sedge

    Very rare

    Marshy fields should be cut for hay and the aftermath grazed.

    Bulwick, Wansford

    Northern lapwing

    Breeding

    Maintain short vegetation structure of open aspect, with numerous flooded shallow scrapes/grips.

    Wadenhoe, Earls Barton Gravel Pit, Brampton Valley.

    Pennyroyal

    Very rare

    Requires short turf in areas disturbed by grazing, trampling or vehicles.

    Abington Meadows CWSs.

    Targets

    Target Code

    Target Type

    Target Description

    Target Units

    Northants Baseline Resource

    Target

    By

    Unit Cost £

    Total Cost £

    NOR_FGM_T1

    Maintain Extent

    Maintain the current extent of BAP-defined Floodplain Grazing Marsh (no loss of BAP habitat).

    Hectares

    259

    No Loss

    2015

    200/ha/yr

    51,800/yr

    NOR_FGM_T2

    Achieving Condition

    Maintain the condition of FPGM habitat where already LWS standard and establish by 2015, management to reach LWS standard for 5 ha of grazing marsh currently not classed as LWS.

    Hectares

    15.25

    20.25

    2015

    200/ha/yr

    1,000 initial + 1,000/yr

    NOR_FGM_T3

    Restoration

    Restore 5 ha of relict Floodplain Grazing Marsh from degraded sites no longer meeting BAP definition (e.g. agriculturally improved or with poor hydrological regime) by 2015.

    Hectares

    0

    5

    2015

    1280/ha

    6,400 initial

    NOR_FGM_T4

    Expansion

    Establish 5 ha of BAP-defined Floodplain Grazing Marsh (which is capable of supporting a diverse range of invertebrates, mammals and breeding waders) from arable land by 2015.

    Hectares

    0

    5

    2015

    1,280/ha + 315/ha/yr

    6,480 initial + 1,575/yr

     Actions

    Action Code

    Action Description

    Lead Partner

    Support Partner(s)

    Related Target

    NOR_FGM_SU_A1

    Identify the current extent of BAP-defined FGM by 2010.

    NBRC

    NBP

    NOR_FGM_T1

    NOR_FGM_CA_A2

    Provide management advice to landowners of current FGM sites to maintain condition by 2012.

    The Wildlife Trust

    NBP

    NOR_FGM_T1

    NOR_FGM_SP_A3

    Respond to all planning applications and other proposals subject to a consenting scheme where these have the potential to damage or destroy the features of interest of FGM designated as LWS or SSSI.

    The Wildlife Trust

    RSPB

    NOR_FGM_T1

    NOR_FGM_CA_A4

    By 2015 establish management to reach LWS standard on 5 ha of FGM in the Nene Valley currently not classed as LWS.

    The Wildlife Trust

    NOR_FGM_T2

    NOR_FGM_HC_A5

    Restore 5 ha of relict FGM from degraded sites no longer meeting BAP definition (e.g. agriculturally improved or with poor hydrological regime) by 2015.

    The Wildlife Trust

    Natural England

    NOR_FGM_T3

    NOR_FGM_HC_A6

    Help landowners and mineral companies establish 10 ha of BAP-defined FGM from arable land in the Earls Barton West area by 2015, following restoration of sand and gravel quarries.

    RSPB

    The Wildlife Trust

    NOR_FGM_T4

    NOR_FGM_CA_A7

    Advise planning authorities, landowners and mineral companies on creating FGM as part of applications for mineral quarrying in the Earls Barton area, to contribute to an overall long term target beyond 2015 of c.100-200 hectares.

    RSPB

    The Wildlife Trust, Natural England , Environment Agency

    NOR_RBD_T3