Overuse of sand dunes - grazing and other agricultural use

Whilst continued grazing is necessary for the survival of the rich plant communities on sand dunes, overgrazing by cattle and/or sheep, particularly when combined with burrowing rabbits can lead to unstable conditions and eventually, large-scale erosion. This has affected a number of machair sites as well as several more typical dune formations such as at Aberffraw in Wales and Braunton Burrows in south west England.

Heathland vegetation which develops on acid dunes is very vulnerable to grazing and even quite low levels may cause losses, as has occurred at Earlshall Muir (Leach 1985). Here and on the Lindisfarne NNR in Northumberland there has been considerable fragmentation of the heath due to overgrazing. In the latter case this was accompanied by supplementary feeding on the dunes which helped to ensure high stocking levels even when grazing was limited in availability. Trampling and eutrophication further reduced the dune heath particularly in the vicinity of the feeding point (Personal observation JPD). These effects and those on dune grasslands have helped identify an number of caveats to the introduction of stock on sand dunes.

Further direct losses of semi-natural dune grassland to agriculture through harrowing and reseeding has occurred at a number of sites including Dunbarnie Links SSSI, Fife and Aberlady Bay Dunes, Lothian (personal observation JPD). Discussion have also taken place over a proposal to reseed part of the Earlshall Muir dune system in Fife and increase stocking levels (Leach 1985).

Comment: Proposals to improve and intensify agricultural use are much less prevalent today than formerly. At many sites undergrazing is a much more of a management issue, leading to State 3 'fixed' dune.

References

Leach, S. 1985. The problem of setting grazing levels on dune-heath Earlshall Muir, Fife. Sand Dunes and their Management