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Shingle vegetation - summary
Shingle beaches are by their nature ephemeral
and prone to sometimes massive and rapid change. The plants and animals, which
survive there are therefore usually tolerant of periodic disturbance. However,
once the ridges become stabilised and out of reach of storm waves, a gradual
build-up of interstitial sediment takes place and with it the development of
a more mature and stable vegetation. At this stage the communities are adapted
to highly stressful conditions involving lack of water and substantial temperature
fluctuations, not dissimilar to those of some deserts. Although such species
are highly tolerant of such conditions they are much more sensitive to disturbance.
The severe limitations
on the ability of plants to colonise and form a closed vegetation on shingle
beaches particularly centre around two principle factors:
- Stability
and size of pebbles;
- The amount of fine
material within the shingle matrix.
In their turn these influence the hydrology of the substrate and soil
development, two further crucial factors in determining whether vegetation
becomes established at all, even on the most stable surfaces. In the early stages
classic pioneer
species on the seaward edge of the shingle include sea kale Crambe
maritima, sea pea Lathyrus japonicus,
Babington's orache Atriplex glabriuscula,
sea beet Beta vulgaris and sea campion Silene
uniflora; species that can withstand exposure to salt spray and some
degree of burial or erosion. The type of vegetation, which then develops is
further influenced by other factors including:
Moving away from the shore, where conditions are more stable, mixed communities
with mature grassland, lowland heath, moss and lichen communities, or even scrub
can develop. Taken together these factors have resulted in a range and variation
of coastal vegetated shingle, which in Great
Britain, at least, are of considerable nature conservation significance.
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