Very Rare Plants on Stanpit Marsh

We hope to supply photos of each of these plants.

Go to Survey & Descriptions of Plants on Stanpit Marsh

Therophyte community

Location:
Compartments: Grimmery Bank, Crouch Hill.
Area: < 0.1 ha.

Description and management rationale:
The drought-prone sandy soils locally support a suite of plants that aestivate. That is, they survive the summer as seeds or bulbous propagules. Many of these are scarce nationally because they cannot compete with more vigorous species in less stressful habitats. A certain amount of trampling assists in keeping the habitat open.

Typical species are Poa bulbosa, Trifolium glomeratum, T.suffocatum, T.scabrum, Moenchia erecta. These plants can survive in quite small patches along footpath margins where the soil is free draining

Dwarf spikerush

Location
Compartments: Parky Meade Rail (map 5)
Area: < 0.1 ha

Dwarf spikerush forms part of the special interest of the SSSI.

Description and management rationale
Dwarf spikerush (Eleocharis parvula) is a very rare plant in Britain. It is classed as vulnerable in the new Red Data Book (Cheffings & Farell 2006) and is protected under the Wildlife and Countryside Act 1981 (schedule 8). It has been monitored intermittently in Parky Meade Rail (Woodhead 1998, 2003) and briefly surveyed in 2006 (appendix 11).

There is a stable and extensive population on the south side of Parky Meade Rail on substrate that is exposed at extreme low tides. This is the Eleocharis parvula saltmarsh community, SM13 in the NVC. Colonies on the north side, by Great Spires were not found in 2006 and the colonies in the lowest reach of Purewell Stream have disappeared except for a very few plants surviving amongst the taller vegetation invading the left bank of the stream as it enters the bay.

The lowest level at which E.parvula can survive is not known for certain, but is expected to be the low water springs. With rising sea levels it is likely that the colony will be lost from its present site within 30 years and there is a risk it will be lost from the harbour altogether if it cannot migrate up-stream. A confounding factor is that at Stanpit it only grows in gravel based substrates. With rising water levels, any material accumulating on the bed will probably be silty or organic in nature. This could smother the plants, even if water levels are suitable.

Dwarf spike rush is the only red data book plant on the marsh, requiring a specific habitat which is itself scarce and declining and the only protected plant species. A number of other rare and scarce plants are to be found. To some extent their management is incorporated into the prescription for the habitat in which they grow.

 

Scarce Plants on Stanpit Marsh

 

botanical name	vernacular name	location †	habitat	10km sq º
Eleocharis parvula	dwarf spike-rush	Parky Meade Rail	upper limit of tidal influence, avoiding strongly saline areas.	10
Alopecurus × plettkei	hybrid foxtail	South Marsh	damp grassland near the sea	9
Epipactis phyllanthes var.vectensis	Isle of Wight helliborine	Waterloo stream	sparsely vegetated, shaded places	90*
Alopecurus bulbosus	bulbous foxtail	South Marsh	coastal grazing marsh	58
Poa bulbosa	bulbous meadowgrass	Grimmery bank	well drained and trampled soil	58
Puccinellia fasciculata	Borrer’s saltmarsh grass	East  Marsh	doubtful	68
Trifolium.suffocatum	suffocated clover	Crouch Hill	well drained and trampled soil	75
Althea officinalis	marsh mallow	North Scrubs, Ship in Distress; East Marsh	Transition zone between the upper saltmarsh and freshwater habitats. Intolerant of grazing.	77
Limosella aquatica	mudwort	Priory Marsh	muddy edges of pools and ditches	80
Vulpia ciliata	bearded fescue	Crouch Hill, Grimmery Bank	disturbed sandy soil	80
Lotus subbiflorus	hairy birdsfoot trefoil	North Scrubs	dry, open grassland on relatively sheltered banks	84
Parapholis incurva		doubtful		85
Crassula tillea	mossy stonecrop	1980	well drained and trampled soil	91
Trifolium glomeratum	clustered clover	Grimmery bank	well drained and trampled soil	94
Moenchia erecta	upright chickweed	Crouch Hill	well drained and trampled soil	182
Ruppia maritima	beaked tassel weed	Central and Grimmery marshes	shallow water in coastal lakes, pools on saltmarshes and ditches near the sea.	208
Stellaria palustris	marsh stitchwort	Priory Marsh	doubtful	212
Ranunculus baudotii	brackish water crowfoot	Central and Grimmery marshes	brackish pools and rills	234
Parapholis strigosa	hard grass	1994	doubtful	291
Puccinellia distans	reflexed saltmarsh grass	Central and East  marshes	doubtful	323
Isolepis cernua	slender clubrush	1980	doubtful	323
Atriplex litoralis		1980	doubtful	333
Apium graveolens	wild celery	Mother Siller’s Channel, Speller’s Point	Sea-walls, beside brackish ditches and the uppermost saltmarshes	348
Carduus tenuiflorus	slender thistle	Grimmery bank	dry, coastal grasslands	389
Anthriscus caucalis	bur chervil	South Marsh	doubtful	423
Oenanthe lachenalii	parsley water dropwort	Central Marsh	saltmarsh	427
Eleocharis uniglumis	slender spike-rush	Priory Marsh	brackish grassland and base-rich, wet meadows	435
Butomus umbellatus	flowering rush	Purewell Stream, Priory Marsh	At the edges of ditches and swamps; often eutrophic	478
Hippuris vulgaris	mares-tail	Central Marsh	at edge of and ponds, in swamps	1054

            †  Where the location is not clear the date of the last record is entered in this column
*  No data available for the subspecies, this is the number for all forms of the species
º The number if 10km national grid squares the species has been recoded as native since 1987 in the New Atlas
        (Preston et al. 2002)