Geoscience Reference
In-Depth Information
Impact of human activities on sand dunes
HUMAN IMPACT
Sand dunes can be rapidly and significantly altered by human activities, and many dune systems will not show the
psammosere succession running its full course to an end point of woodland. The degree of impact will reflect the
density and pressure from surrounding settlement, so that in general the sand dunes of England have been more
affected than those of Wales and Scotland. However, land use policies are also important; dune woodlands are
common in the Netherlands, for example, where there is less use of dunes for animal grazing. Agriculture, recreation,
urban and industrial development, sea defence works, forestry, waste disposal, military use and nature conservation
all impact upon plant and animal life.
In England most dunes have been grazed by sheep, cattle and rabbits for many centuries. This favours grass and
heath plant communities. If grazing is removed the succession enters a new stage. Woody species rapidly invade
and scrub develops, especially sea buckthorn (Hippophae rhamnoides). A wide range of other shrub and tree species
can grow on dunes in the absence of grazing. In north-east England at Ross Links and Druridge Bay, Northumberland,
the use of dunes as winter holding grounds for cattle results in manure and nutrient inputs which alter the dune
vegetation. A wide range of agricultural improvements such as reseeding, ploughing, fertilizing, drainage, irrigation
and herbicides all take place. Recreation is a major form of land use and probably affects more dunes than grazing.
Use for golf courses is long-standing since the origins of 'links' in eastern Scotland, but visitor pressure on paths
causes erosion widely throughout England and Wales. The severest erosion occurs near facilities such as caravan
sites and car parks in popular tourist areas like Cornwall. Urban development has been extensive adjacent to dunes
along the Sefton coast, Merseyside, the Fylde coast dunes in Lancashire, Berrow dunes in Somerset, and in Sandwich
Bay, Kent. This is also a problem on popular tourist coasts around the Mediterranean (
Plate 20.5
).
Sea defence works are very common and range from 'hard' systems like sea walls, groynes, gabions, piles and
boulders. Other methods are beach reprofiling, fencing, brushwood, and planting of marram and sea buckthorn.
Forestry has not been common in England, except for Sefton dunes, Merseyside, and Holkham dunes, Norfolk. It
has been much more widespread in Wales, e.g. Newborough, Angelsey, and Scotland, e.g. Culbin Forest, Moray
Firth. Military use was clearly more important during the Second World War, but there are still many relicts in the
form of pillboxes and anti-tank installations.
Nature conservation is a recent but important land use on many sand dunes. Often it occupies only a small part of
the site, but also it frequently is the primary use. It reduces the impact of other activities, and affects the course of
natural succession through programmes of scrub clearance and reintroduced grazing. Conservation bodies involved
in sand dune management for wildlife are Natural England (National Nature Reserves, NNRs; Sites of Special Scientific
Interest, SSSIs), the National Trust, the Royal Society for the Protection of Birds (RSPB) and county wildlife trusts.
Sand dunes may also have a European Designation, as in the Special Area of Conservation (SAC) of the Sefton coast.
Education and involvement of the public frequently take place in sand dune systems with areas designated for nature
conservation.
Ainsdale Sand Dunes NNR on the Sefton coast of north-west England is one of the finest dune systems of England,
recording over 450 plant species with many rarities such as seaside centaury, yellow bartsia, round-leaved wintergreen
and dune helleborine. The value of the different habitats within the dune system is summarized in
Table 20.5
.
Dune habitat
Plant and animal wildlife
Intertidal sand flats
Feeding grounds for wading birds and gulls
Yellow dunes
Sand lizards
Dune slacks
Great crested newts, natterjack toads
Dune grassland
Purple field gentian, round-leaved wintergreen, grass of Parnassus, early marsh orchid,
pyramidal orchid, dune helleborine
Pinewood
Red squirrels, 400 species of fungi
