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Geographical variation of saltmarsh vegetation
Saltmarsh plant community mosaics are only one part of the story. From a nature
conservation point of view their geographical range is also significant.
Saltmarshes in Great Britain vary in composition from north to south. This
variation provides a link between the saltmarshes of the Mediterranean (including
the 'Dry coast' type of Adam 1990) and the
Arctic. In addition there are east/west gradients which help to define the three
main types characteristic of the region (Adam 1978;
Adam 1981).
| Region |
Vegetation characteristics |
| Southeast England |
Presence of common glasswort Salicornia
europaea in the low marsh and sea purslane Atriplex
portulacoides and cord-grass Spartina
anglica in the mid-marsh |
| Northwest England and Wales |
Saltmarshes are more grassy and have an abundance of saltmarsh
rush Juncus gerardii in the mid-upper
levels |
| Western Scotland |
Marshes of have a greater proportion of upper marsh communities
but fewer halophytes |
Comment: Differences between east and west marshes are attributed
to a combination of heavier grazing and sandier substrate in the west when compared
with lighter grazing (or no grazing) and muddy estuarine substrates in the east.
The presence of sea heath Frankenia laevis
and shrubby sea-blite Suaeda vera, in North
Norfolk, help define links with saltmarshes of the Mediterranean where these
species are widespread. For a detailed description of saltmarsh vegetation world-wide
see (Adam 1990 Chapter 3).
References
Adam, P.
1978.
Geographical variation in British saltmarsh vegetation.
Journal of Ecology, 66., 339-366.
Adam, P.
1981.
Vegetation of British saltmarshes.
New Phytologist, 88., 143-196.
Adam, P.
1990.
Saltmarsh Ecology. Cambridge University Press, Cambridge, 461 pp.
Cambridge Studies in Ecology
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