Using pigs in conservation grazing

When conservation grazing is mentioned you would usually think of cattle, sheep or equines. However, our native pigs play an important part in conserving and managing woodland and other habitats.

Wild and domestic pigs were once common in the British woodland landscape. Traditional British breeds such as Gloucester Old Spot, Oxford Sandy and Black, British Saddleback or Tamworth pigs tend to be hardier, more suitable for feeding on a variety of food foraged for themselves and some are less prone to sun burn. The traditional breeds are more varied in their appearance and have usually been developed under different commercial requirements to modern breeds. Whereas commercial pigs tend to be selected for higher reproduction rates and low fat carcasses, traditional breeds generally have higher fat levels which may account for their hardiness. Most traditional breeds are able to tolerate outwintering provided they are well fed and can find shelter from the wind in a suitable environment.

Unfortunately, many see pigs as destructive. Contrary to popular belief, pigs do not uproot everything. They willingly graze, browse and consume berries and fungi, and have been known to take invertebrates which helps to create and maintain a mosaic of bare ground, herb rich pasture and shrub layer. These behavioural characteristics and their resulting impact are almost impossible to replicate using other forms of management. Their rooting behaviour can clear dense ground vegetation such as bracken, reducing the need for weed control and creating seed beds for natural regeneration.

When using pigs for conservation work the aims of the project should be clear - what will be removed, what will be conserved and what will be encouraged – as should the implications of the time of year the pigs are released on site, the length of time they have to work and how their impact will be monitored.

Depending on the outcome of these assessments, appropriate stocking density and timing will vary, perhaps requiring a few pigs over a larger area or high numbers used intensively. At low densities, pigs will dig some areas forsaking others. More intensive rooting resulting from higher stocking densities can be useful in forestry plantations e.g. for preparing the soil for planting or natural regeneration. If plenty of varied food is available there may be no need for supplementary feeding but in some cases some supplements may be necessary and can help to keep animals easier to handle. Some breeds may live on grass from May to September.

Native traditional pigs have been used successfully for conservation grazing and land management in a variety of locations. Dense oak stands in the Wyre Forest were opened up to restore old coppice plots relying on natural regeneration. Growth of bracken and bramble was preventing the growth of new oaks in some areas so pigs were turned out in mid-summer to break up this growth, creating bare patches and allowing light to reach acorns from the remaining oaks which resulted in the growth of new oaks. Removing pigs from the site before acorns fall in the autumn ensures they aren’t eaten.

In other parts of the forest, pigs have been used in areas cleared of western hemlock to intensively clear hemlock seedlings and saplings, and to break up the ground in preparation for planting or natural regeneration of native broadleaves. Pigs usually only disturb young trees, saplings and seedlings once all other food sources have been exhausted so with the correct stocking densities, they can be used effectively to reduce competition between trees and other vegetation in a regenerative area. Conversely, they can also be used to reduce tree regeneration by eating tree seeds if they are left on site in autumn.

In the New Forest between 200 and 600 pigs are used to carry out a practice known as Pannage each autumn. This involves releasing domestic pigs in woodland so that they feed on fallen acorns, beechmast, chestnuts or other nuts. Pannage is carried out to reduce the amount of these nuts on the woodland floor as excessive amounts can be poisonous to grazing ponies and cattle. Starting at the end of September it lasts a few months depending on seasonal variations. To stop pigs causing damage to the woodland floor through rooting, rings are often placed through their noses and removed once Pannage has been completed. Control of Gaultheria, an introduced plant species, has also been achieved in the New Forest by using pigs.

At Burnham Beeches pigs were used in management for 15 years. Each autumn, a small number of pigs were used in the wood pasture system to create bare patches of ground through rooting behaviour. This produced seed beds suitable for ruderal species, exposed dormant heather and enabled other seeds to germinate. They were also used under the canopy for Bracken control. Experiments at Burnham Beeches, Langley and Fairbirch Woods showed the use of pigs to be extremely effective, reducing the problem of bracken litter by gathering it for bedding. By breaking up the dense bracken litter/soil layer pigs enable germination of more desirable vegetation and increase patchiness and the development of micro-climates.

Pigs have also been used by the Dunlossit Estate for bracken control in variety of different habitats including moorland, coastal woodland, coppiced woodland and rape fields. It was noticed that given a varied environment they had selected bracken, ignoring everything else. The undergrowth was stripped to soil and showed reduced bracken growth in later years.

Pigs are also useful in the management of Rhododendron, supporting management by improving access to the woodland floor for silviculture to commence. They can also be used after removal to break up the leaf litter, allowing light to the woodland floor and natural regeneration to occur as well as suppressing any new growth of Rhododendron. Though pigs won’t eradicate Rhododendron themselves, they are an excellent alternative to herbicides and machinery.

From the Lops and the Berkshire to the British Landrace and the Middle White, our traditional pig breeds are ingenious, intelligent, hardy and adaptable. They thrive in a variety of habitats and can offer conservation solutions that are less destructive than mechanical or chemical intervention. The beneficial effects of pigs in conservation grazing and land management are many and include: acting as a natural predator for invasive species, reducing ground layer density, increasing dead wood percentage, breaking up soil, generating nesting materials and clearing or thinning vegetation.