Management of Archaeological Sites on Grassland
Grassland management has ensured that many archaeological sites have survived to the present day in far better condition than those in cultivated land. This is particularly true for areas of unimproved permanent grazing land, where some of the nation’s best-preserved archaeological sites survive often as earthworks. Maintaining these sites in grassland is the best form of management, ensuring their long-term preservation and visibility.
However, careful management is essential. Harm can result from livestock poaching or erosion, careless use of farm vehicles, grassland improvement, land drainage works, scrub or bracken encroachment, burrowing animals, new fencing, new ponds or scrapes, and tree planting.
Prevention is better than cure. There may be signs that the site is coming under stress and action should be taken to alleviate the problem. It is important to seek professional archaeological advice before attempting repairs.
All known sites are recorded on Historic Environment Records maintained by local authorities. However there are many sites yet to be discovered.
Nationally important sites are protected by law from damaging works as scheduled monuments and consent is needed ahead of carrying out works.
Livestock poaching or erosion
All livestock can damage archaeological sites through poaching or creating erosion scars. This can cause significant disfigurement to the site and damage to the information it holds. Sometimes this happens just through over-stocking, but more commonly it is associated with livestock movement or gathering points, such as gateways, water troughs, feeders or trees. Stock erosion can also be a particular problem around monuments such as standing stones or ruinous structures. Erosion scars will often continue to develop if not repaired. Small scars can be stabilised by removing stock and allowing grass to regenerate. Larger scars will need careful repair with turves or soil.
Options to consider:
- Re-site places where livestock gather (such as water troughs or gateways) to less sensitive areas
- Regularly move mobile feeders to minimise impact
- Plan new or adjust existing shelterbelts so that livestock do not gather on archaeological sites
- Exclude livestock temporarily from damaged areas to allow recovery of erosion scars
- Exclude livestock during wet conditions when the monument is more vulnerable
- Adjust stocking levels (particularly for larger livestock, such as cattle and horses, which cause greater disturbance to earthworks) or change stock to a lighter type to minimise the potential for damage
- Maintain stock-proof boundaries in good condition
Farm vehicles
Farm vehicles can cause significant disfigurement and damage to archaeological sites through the creation of wheel ruts. This is a particular problem on waterlogged soils. The ruts can then lead to further erosion, especially on a slope. The area of disturbance can also spread as new routes are sought across the site.
Options to consider:
- Use an alternative route away from the archaeological site
- At critical times of the year, use lighter vehicles or vehicles fitted with low ground pressure tyres, and lighten loads
- Create a single permanent route; this may require major ground disturbance, so always take archaeological advice before carrying out work
Grassland improvement
Archaeological sites in grassland are often important for their wildlife, particularly where they survive in unimproved pasture. These sites often contain rare plants and should be carefully managed to conserve both their archaeological and ecological interest.
Where there is no grassland of nature conservation interest on archaeological sites, the application of fertilisers is unlikely to damage the ancient remains.
It may nevertheless be desirable to reduce the intensity of management in order to improve the species richness of the grass sward. If the grassland does need to be improved further, then methods such as direct drilling and seed slotting, which cause minimal disturbance, should be used.
Options to consider:
- Control weeds by topping or targeted use of selective herbicides following the Plant Protection Products Regulations and Health and Safety Executive Codes of Practice and guidance
- If re-seeding is required, use minimal cultivation techniques
Land drainage works
Land drainage is an important element of grassland management as it assists in maintaining good grass yields. A well-maintained land drainage system can be beneficial to archaeological preservation, helping to prevent surface waterlogging, poaching by livestock and the silting up of features such as ditches. However, the installation and maintenance of drainage systems can be damaging to archaeological sites.
This is particularly true of old tile drains as these may be buried at some depth within archaeological deposits and require excavation in order to effect repairs. Equally, new land drains may dry out previously waterlogged below-ground archaeological deposits, including important organic artefacts or environmental remains, all of which help to piece together a more complete picture of what the landscape looked like in the past.
Options to consider:
- Install access points outside the archaeological site to permit the land drains through the site to be maintained without the need for excavation
- If new land drains are being installed, ensure that these are away from the archaeological site
Scrub encroachment
Insufficient grazing can permit the development of scrub and weeds on a monument. Scrub causes significant damage to archaeological sites through root penetration, providing cover for burrowing animals and shelter for livestock.
It is therefore desirable to reduce the amount of scrub on an archaeological site to reduce this damage and maintain the visibility of earthworks. However, scrub can be of ecological importance, and the wildlife impacts of scrub clearance should be considered before commencing work. Extensive clearance should be phased. Scrub should not be removed by mechanical means as this could damage the archaeology. Instead, stumps should be cut close to ground level and treated with herbicide to prevent re-growth. The cut material should be disposed of well away from the archaeological site.
Options to consider:
- Increase grazing where practical to help control scrub growth
- Control scrub by cutting and treating with a herbicide to prevent re-growth subject to following Plant Protection Products Regulations and Health and Safety Executive Codes of Practice and guidance
Bracken is also highly damaging to archaeological sites because it develops a dense layer of rhizomes below ground. Our section on bracken provides management advice.
Burrowing animals
Archaeological sites in grassland, which mostly survive as earthworks, are particularly attractive to burrowing animals such as rabbits and moles because they contain well drained and easily tunnelled soils. Burrowing not only disturbs important archaeological remains but also leads to earthworks losing their form through collapse. Livestock can also turn burrow entrances into erosion scars.
Options to consider:
- Humane control of burrowing animal populations
- Block up burrow entrances
- Wire netting to exclude rabbits
When controlling rabbits the wire netting mesh size must be no larger than 90mm. If areas are to be fenced, you may need scheduled monument consent. If fencing an earthwork, the netting needs to be 750mm high and at ground level the netting needs to be lapped at least 150mm and securely pegged so the rabbits cannot get into the fenced area.
Netting can also be laid over the surface of an archaeological earthwork. It needs to extend at least 300mm beyond the limit of the earthwork slope. If more than one width of netting is needed, the width will need to be overlapped. The netting needs to be pegged at regular intervals. After about a year, vegetation will grow through the netting to help anchor it. The netting will need periodic repair and replacement. Laid netting is not suitable for mown sites as the wire will get caught up in the machinery.
Our web section on badgers provides further guidance on managing badgers when they are causing damage.
New fencing, ponds and scrapes, and tree planting
Erecting fencing, digging ponds or scrapes, and tree planting are all likely to disturb underlying archaeology. Fence lines can also cause poaching, and tree roots will cause further disturbance as they grow.
Options to consider:
- Place fences away from archaeological sites wherever possible
- Do not site ponds or scrapes on archaeological sites
- Do not plant trees on archaeological sites without expert advice
Anthills
Anthills are created by yellow ants, Lasius flavus. These soil domes help regulate the temperature and humidity of the nest below. Anthills, like ridge and furrow, are an indicator of ancient grassland. The ants have a role in developing long-lasting soil structure which in turn influences the biodiversity of the grassland. Generally, these grasslands should be grazed. If there are problems with pregnant sheep rolling over and not being able to stand up or 'cast', the solution may be to only graze these fields in summer months.
Grants
The Countryside Strewardship Scheme includes a funding option for historic and archaeological feature protection.
