Coastal and Floodplain Grazing Marshes
Wet pastures or meadows on the coast or in river valley floodplains, which lie at, or below, sea level and may be enclosed by seawalls.
Periodically inundated or bounded by ditches with high water levels and may have water-filled hollows or ponds with emergent swamp communities.
Almost all are grazed primarily by cattle and some are cut for hay or silage.
Importance for wildlife
The mosaic of habitats supports many plants, invertebrates, birds and mammals. They are particularly good for breeding waders and support internationally important flocks of wintering birds. In coastal areas, the dyke systems provide a brackish habitat for estuarine species. The seasonal inundation gives the vegetation a distinct composition. Many grazing marshes have dyke systems rich in flora and fauna, supporting a variety of marginal and aquatic plant species and invertebrates.
Important associated species
- Common Starling Turdus philomelos
- Black-tailed Godwit Limosa limosa
- Common Grasshopper Warbler Locustella naevia
- Yellow Wagtail Motacilla flava
- Skylark Alauda arvensis
- Eurasian Curlew Numenius arquata
- Northern Lapwing Vanellus vanellus
- Barn owl Tyto alba*
- Water Vole Arvicola amphibius
- Barbastelle Bat Barbastella barbastellus
- Noctule Bat Nyctalus noctula
- Serotine Bat Eptesicus serotinus
Bees and Wasps
- Moss Carder Bee Bombus muscorum
- Fen Mason-wasp Odynerus simillimus
- Wall Lasiommata megera
- Zircon Reed Beetle Donacia aquatica
- Norfolk Hawker Aeshna isosceles
- Little whirlpool Ram’s-horn Snail Anisus vorticulus
- Depressed River Mussel Pseudanodonta complanata
- Shining Ram’s-horn Snail Segmentina nitida
- Large-mouthed Valve Snail Valvata macrostoma
- Desmoulin’s whorl Snail Vertigo moulinsiana
- Narrow-mouth whorl Snail Vertigo angustior
- Swollen Spire Snail Mercuria similis
- Fen Raft Spider Dolomedes plantarius
- Tassel Stonewort Tolypella intricata
- Flat Sedge Blysmus compressus
- Slender Hare’s-ear Bupleurum tenuissimum
- Divided Sedge Carex divisa
- Sea Barley Hordeum marinum
- Tubular Water-dropwort Oenanthe fistulosa
- Borrer’s Saltmarsh-grass Puccinellia fasciculata
- Greater Water-parsnip Sium latifolium
- Marsh Stitchwort Stellaria palustris
- Native Black Poplar Populus nigra spp betulifolia*
*Suffolk Priority species
Factors affecting habitat in Suffolk
- Changes to salinity levels can alter species composition. This may be caused by sea-level rise and increasing numbers of storm surge events. Brackish transition communities can be valuable e.g. Minsmere South Levels.
- Impacts of drought and excessive groundwater abstraction.
- Agricultural intensification including over-grazing and spray drift from surrounding agricultural land.
- Inappropriate dyke management i.e. excessive dredging and maintaining low water levels instead of allowing natural rise and fall.
- Alien invasive species such as Floating Water Pennywort, Parrot’s Feather and Crassula helmsii choke waterways and outcompete native species. American Mink feed on water voles and other native species.
Habitat management advice
- Maintain habitat diversity to include bare ground, patchy scrub, varying grass heights and temporary pools.
- Manage saline incursion and flooding where possible.
- Maintain light grazing, preferably with cattle over the autumn, winter and spring months.
- Manage drainage ditches for invertebrates using a rotational management plan and clearing only one side of a ditch at a time.
- Maintain a high water level in ditches throughout the year if possible.
- Encourage diverse marginal vegetation through mild poaching by cattle (don’t fence off all the dykes).
- Create varied ditch profiles to create diverse habitats; slopes of less than 35o provide optimum conditions.
- Maintain water quality by reducing any nutrient input from fertiliser or livestock feed and preventing any pesticide residues entering the water.
- Maintain a stable salinity in brackish ditches and waterbodies i.e. do not flush with fresh water.
- Maintain an open landscape with occasional hedges, trees and bushes by preventing the incursion of scrub.
- Ensure bird roosts are not disturbed e.g. by walkers or their dogs.
Vision for Suffolk
- Improve knowledge of the extent and quality of coastal and floodplain grazing marsh.
- Maintain the existing extent of coastal and floodplain grazing marsh to ensure no net loss.
- Encourage the restoration and improvement of degraded coastal and floodplain grazing marsh.
- Re-create coastal and floodplain grazing marsh as opportunities arise.
Where to find further information
- Buglife – advice on managing BAP habitats
- Buglife – Notable invertebrates (pdf)
- JNCC – Habitat Description (pdf)
- MAGIC website – interactive mapping information including designations
- Making Space for Nature, a Review of England’s Wildlife Sites and Ecological Network 16 Sep 2010. Chaired by Professor Sir John Lawton CBE FRS. Defra website (pdf)
- Natural Environment White Paper June 2011 – The Natural Choice: securing the value of nature (pdf)
- Suffolk Wildlife Trust – Habitats Explorer
* all the links marked (pdf) have been gathered into an Issuu stack
- Cattle grazing at Butley Marshes
- Barn Owl by Stephen Reeve (Flickr)
- Grazing at Boyton Marshes by Emma Aldous
- Water Vole by Margaret Holland (Flickr)