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Abandoned (State 4) saltmarsh - re-introduce grazing
This is the most frequently encountered restoration need when considering saltmarsh
vegetation. The dominance of grasses in the heavily grazed saltmarsh (State
1) and their ability to grow more vigorously as grazing pressure
is reduced, combine to produce a sward which is less and less palatable for
grazing ducks and geese. This loss of interest together with other species eliminated
as the vegetation becomes denser can be addressed by reintroducing grazing.
On the longest abandoned swards, with the most matted vegetation, initially
high stock densities may be required to open up the sward. Thereafter the grazing
regimes will need to be applied in accordance with those applied to heavily
grazed (State
1) or moderately grazed (State
2) saltmarshes. [The precise regime to be adopted will generally
be determined by nature of the biodiversity
interest to be restored.]
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Guidance: Mowing can reverse the matted growth of vegetation on
abandoned saltmarshes. However, although mowing increases species diversity
initially, a turf of Festuca rubra
is produced and a decrease in plant diversity occurs after only 5 years.
In contrast, re-introduction of cattle grazing alone enhanced species
diversity and was attributed to gradual litter decomposition by trampling
(Cadwalladr & Morley 1971 and
Cadwalladr et al. 1972).
Where grazing has been recently abandoned it should be reintroduced.
Whilst high initial stocking levels may be needed to open up the dense
turf, the most diverse conservation interest will be attained by using
the low level, open range grazing
regimes identified above as being appropriate to moderately
grazed (State
2) saltmarsh vegetation. Chapter 5 (Doody
2001).
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References
Cadwalladr, D.A. & Morley, J.V.
1971.
Further experiments on the management of saltings pasture for wigeon (Anas penelope L.) conservation at Bridgwater Bay National Nature Reserve, Somerset.
Journal of Applied Ecology, 10., 161-166.
Cadwalladr, D.A., Owen, M., Morley, J.V. & Cook, R.S.
1972.
Wigeon (Anas penelope L.) conservation and salting pasture management at Bridgwater Bay, National Nature Reserve, Somerset.
Journal of Applied Ecology, 9., 117-126.
Doody, J.P.
2001.
Coastal Conservation and Management: an Ecological Perspective. Kluwer, Academic Publishers, Boston, USA, 306 pp.
Conservation Biology Series, 13
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