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Braunton Burrows - summary
Braunton Burrows lies on the west facing coast of Devon in the south west of
England. It is a large (1,357ha) bay dune system of both biological and geomorphological
importance. An early description of the vegetation (Willis
et al. 1959) helps provide a basis for assessing change. The high diversity
of the vegetation arose as a result of low nutrient status and grazing (by rabbits
until the outbreak of myxomatosis in 1953) and the inherent dynamic of the system.
This 'natural' balance was disturbed during the 1940s when practice amphibious
landings by tracked vehicles took place. This resulted in massive destabilisation
which by the early 1950s had made large areas look like a "semi-desert
of shifting sand" (Breeds & Rogers 1998).
This massive destabilisation of the dune prompted a major dune
planting programme using a combination of sand
fencing, marram
planting and sea buckthorn Hippophae introduction.
Loss of domestic stock and reduced rabbit numbers combined to accelerate the
stabilisation of the surface sand. Lowering the dune water table, possibly as
a result of drainage nearby, may have further increased the rate of stabilisation.
By the mid 1970s the open, 'eroding' dune had been transformed to a much more
closed, stable
dune surface. By the early 1980s the growth of course grasses and
scrub was beginning to cause concern as the features for which the site had
been identified as a Nature
Conservation Review Site (Ratcliffe 1977)
and designated as a Site
of Special Scientific Interest and established as a National
Nature Reserve were threatened. Of particular concern was the invasion by
Hippophae rhamnoides
which had affected large areas of the site.
Since then restoration management has included:
- Scrub
control - This was concerned principally with the control of Hippophae
rhamnoides. A programme of eradication of the species took place under
the direction of the warden of the National Nature Reserve (Venner
1977). This work was undertaken against a backdrop of a national review
of the species and its effect on areas of nature conservation interest (Ranwell
1972b);
- Introduction of sheep
grazing - from 1987-1996 grazing by Soay sheep was intermittently introduced
into trial paddocks.
In 1997 English Nature’s management guidelines identify three management
needs:
- grazing
(by sheep and cattle), to maintain and, if possible, expand the area of short
turf and keep invasive scrub under control;
- raising the water table, to maintain dune
slack communities;
- keeping the dune system dynamic, with areas of bare, mobile sand, so that
geomorphological and successional processes can continue.
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Guidance: Braunton provides a vivid illustration of the different
perceptions of the status of the dynamics of coastal habitats (especially
sand dunes), which can result when sites are viewed over a relatively
short time frame. The implications of the dune stabilisation programme
were not immediately apparent. But by 1980s concern began to be expressed
at the loss of plant diversity, as the coarse grasses and Hippophae
scrub took hold. In the absence of grazing is also clearly shows how important
mobile dunes and the value of the 'dynamic
dune' are for the conservation of sand dune diversity. This
case is discussed in some detail in relation to sand dune management policy
(see Doody 1989).
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References
Breeds, J. & Rogers, D.
1998.
Dune management without grazing - a cautionary tale.
Enact: Management for Wildlife, 6., 19-22.
Doody, J.P.
1989.
Management for nature conservation.
Royal Society of Edinburgh Proceedings. Section B (Biological Sciences), 96., 247-265.
Abstract...
Ranwell, D.S.
1972b.
The Management of Sea Buckthorn Hippophae rhamnoides on Selected Sites in Great Britain.
Report of the Hippophae Study Group
The Nature Conservancy, Norwich.
Ratcliffe, D.A.
1977.
A Nature Conservation Review: the Selection of Sites of Biological National Importance to Nature Conservation in Britain. 2 Volumes. Cambridge University Press.
Venner, J.
1977.
The Eradication of Hippophae rhamnoides L from the Braunton Burrows Sand Dune System.
Senior Warden Project (unpublished)
Nature Conservancy Council, Oxford.
Willis, A.J., Folkes, B.F., Hope-Simpson, J.F. & Yemm, E.W.
1959.
Braunton Burrows: the dune system and its vegetation.
Journal of Ecology, 47/1., 1-24.
Abstract...
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