Habitat account - Marine, coastal and halophytic habitats


1320 Spartina swards (Spartinion maritimae

Background to selection

Distribution of SACs/SCIs/cSACs with habitat 1320 Spartina swards (Spartinion maritimae).  Click image for enlarged map.
Distribution of SACs/SCIs/cSACs with habitat 1320 Spartina swards (Spartinion maritimae). Click image for enlarged map.

Description and ecological characteristics

 

Cord-grass Spartina spp. colonises a wide range of substrates, from very soft muds to shingle, in areas sheltered from strong wave action. It occurs on the seaward fringes of saltmarshes and creek-sides and may colonise old pans in the upper saltmarsh. The corresponding NVC types are:

 

     

  • SM4  Spartina maritima salt-marsh community
  • SM5  Spartina alterniflora salt-marsh community
  • SM6  Spartina anglica salt-marsh community

 

Four cord-grasses occur in the UK: small cord-grass Spartina maritima, smooth cord-grass S. alterniflora, Townsend’s cord-grass S. x townsendii and common cord-grass S. anglica. The only native species is S. maritima. S. alterniflora is a naturalised non-native species that was accidentally introduced to the UK in the 1820s via ships’ ballast from the eastern USA, where it is a major component of saltmarshes. The introduction of S. alterniflora and its subsequent crossing with S. maritima resulted in both a sterile hybrid S. x townsendii and later a fertile hybrid, S. anglica. Although a non-native, the surviving population of the parent S. alterniflora is of great scientific importance to evolutionary biologists.

 

Spartina anglica was extensively planted in the past as an aid to stabilisation of intertidal mudflats and a stimulus to enclosure and land-claim. It also readily colonises open mudflats and consequently has spread rapidly around the coast. Monoculture swards of either S. anglica or S. x townsendii are of little intrinsic value to wildlife, and in many areas S. anglica is considered a threat to the intertidal mudflats used as feeding-grounds by large populations of waders and wildfowl. As a result, attempts have been made to control S. anglica at several sites over many years, but these have largely been unsuccessful in eliminating it. S. anglica is generally considered to be a negative conservation feature of the sites where it occurs, although in some areas, such as the Dee Estuary, it can act as a pioneer species for the formation of 1330 Atlantic salt meadow (Dargie 2001).

European status and distribution

 

Spartina swards have a wide distribution in the EU, especially on Atlantic coasts.

UK status and distribution Click to view UK distribution of this habitat

 

Spartina maritima, S. alterniflora and S. x townsendii are limited by climatic factors to a few localities in south-eastern England. Since the 1960s, S. alterniflora has declined, largely due to industrial and marine developments, and in the UK it is now restricted to a single site in Southampton Water (Maskell & Raybould 2001). S. maritima has also declined, but there are still substantial populations on the Essex coast. S. x townsendii is present in quantity only in Southampton Water.

 

S. anglica is widespread and locally abundant on saltmarshes in England and Wales, but has only a few scattered localities in Scotland and Northern Ireland.

Site selection rationale

 

In the UK stands of this Annex I type have only been considered for selection as SACs where they are dominated by Spartina maritima, S. alterniflora, or support the rare and local hybrid S. x townsendii. The two significant stands of these species known in the UK have both been included within the SAC series. Monoculture swards of the widely-planted invasive S. anglica have not been considered for SAC selection.


Site accounts

Essex Estuaries Essex, Extra-Regio
The most extensive remaining stand of the native small cord-grass Spartina maritima in the UK and possibly in Europe is found in the Essex Estuaries. The stand is located at Foulness Point and covers approximately 0.17 ha. Other smaller stands are found elsewhere in the estuary complex, notably in the Colne estuary, where it forms a major component of the upper marsh areas.
Solent Maritime Extra-Regio, Hampshire and Isle of Wight, Surrey, East and West Sussex
Solent Maritime is the only site for smooth cord-grass Spartina alterniflora in the UK and is one of only two sites where significant amounts of small cord-grass S. maritima are found. It is also one of the few remaining sites for Townsend’s cord-grass S. x townsendii and holds extensive areas of common cord-grass Spartina anglica, all four taxa thus occurring here in close proximity. It has additional historical and scientific interest as the site where S. alterniflora was first recorded in the UK (1829) and where S. x townsendii and, later, S. anglica first occurred.

SACs/SCIs/cSACs where this Annex I habitat is a qualifying feature, but not a primary reason for site selection

Not applicable.
 

Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.