Prehistoric burial mounds and ceremonial monuments

Overall vulnerability

Feature(s) assessed:

• Neolithic burial mounds - chambered cairn and long barrows
• Bronze Age burial mounds - barrows and cairns
• Stone circles
• Henges

Special qualities:

• Landscapes that tell a story of thousands of years of people, farming and industry

Feature description:

This assessment focuses on Neolithic and Bronze Age burial features. However, many of the potential effects of climate change discussed will apply equally to other prehistoric ceremonial monument types such as henges.

There are currently 34 Neolithic and 238 Bronze Age burial mounds mapped in the PDNP, although the origins of a number of these are unclear and there are many more undated sites. Neolithic chambered cairns typically consist of one or more stone chambers, covered by a mound of stones, into which human remains were placed.

Long barrows are almost always Neolithic in origin and typically consist of a long, roughly rectangular mound of soil or stone containing chambers for the ritual placement of human remains and other grave goods. Although, sometimes only the internal stone chamber survives. They are often located in prominent positions within the landscape.

Bronze Age barrows and cairns consist of a mound of earth or stones covering a central burial place, and there are numerous types and configurations to be found in the PDNP.

Gib Hill, adjacent to the Arbor Low henge in the White Peak is an important example of a Neolithic long barrow. At this site a round barrow was later added to the feature during the Bronze Age. The PDNP is home to several unusual sites with complex history such as the 210-metre-long Long Low site near Wetton.

The features types assessed here are all historically significant, and the PDNP contains some nationally rare and important examples. Collectively they show evidence of settlements and give some insight into how past ceremonies and rituals may have influenced modern day activities.
How vulnerable are prehistoric burial mounds and ceremonial monuments?

Prehistoric burial mounds and ceremonial monuments in the PDNP have been rated ‘high’ on our vulnerability scale. This score is due to high sensitivity and exposure to climate change, a variable current condition and a moderate adaptive capacity.

How vulnerable are prehistoric burial mounds and ceremonial monuments?

Prehistoric burial mounds and ceremonial monuments are in a vulnerable condition, with only half of those known intact. Climate change has the potential to accelerate damage to those structures remaining. Increased damage and attrition rates caused by expansion and contraction of stone and soil structures have the potential to play a role in the collapse of internal chambers. Increased visitor numbers in the PDNP, burrowing animals and future changes to farming practices may be some of the most important climate driven factors to impact these features. These features are an irreplaceable and finite resource, susceptible to damage and loss. However appropriate protections and management should be able to at least partially offset the impacts of climate change. Neolithic sites are likely to be the most vulnerable as an overall resource due to their rarity, while unscheduled and unknown sites will be vulnerable because appropriate management actions are less likely to be put in place.

Current condition:

Of the Neolithic burial mounds mapped in the PDNP, approximately half appear to be intact with the rest either being disturbed or reduced, and around 10% completely destroyed or removed. Information is scarce about those that are mutilated or badly cratered, and many of these will have undergone antiquarian excavations, which were poorly documented.

Nationally, many scheduled ancient monuments are at risk from arable agriculture associated with ploughing and are in declining condition. The predominately pastoral landscape means that to date this has been less of a problem in the PDNP. However, it is likely that some features are impacted by damage from plant growth or burrowing animals. The Heritage at Risk Register notes evidence of extensive badger burrowing in a bowl barrow in the Staffordshire Moorlands causing its condition to be classed as 'generally unsatisfactory with major localised problems'. It is very likely that other monuments in the PDNP face similar risks.

What are the potential impacts of climate change?

Overall potential impact rating

Direct impacts of climate change

It is possible that climate change will contribute to the damage or destruction of irreplaceable prehistoric burial mounds and ceremonial monuments in the PDNP.
Hotter summers and greater extremes of temperature have the potential to accelerate the attritional damage of monument structures through the increased thermal expansion and contraction of soil and stone. Data Certainty: Moderate

The shrink-swell action caused by repeated waterlogging and drying is likely to become more frequent during wetter winters and year-round storm events. This would increase the risk of the internal collapse of chambers within funerary monuments, leading to loss of irreplaceable archaeological information. Features located on clay-rich ground would be the most susceptible to this process. Due to their age, structures may be susceptible to direct erosion from increased hydraulic action. Data Certainty: Moderate

Human behaviour change

Hotter, drier summers are likely to attract more visitors to the PDNP, leading to an increase in footfall, off road vehicle and mountain bike use, and the possibility of an increase in vandalism. This may increase the erosion and damage of monuments and their surroundings. Data Certainty: High

Combined climate effects may create the potential future need and opportunity for more intensive farming and a switch to arable in some places. The production of food or deep-rooted energy crops, the development of new farming infrastructure and the enlargement of fields could put features at risk from direct damage. Although land use changes may create opportunities for new discoveries to be made, these may go unrecorded. There is currently no robust system in place to report, manage and record such ad-hoc discoveries, so evidence may be lost. Data Certainty: High

Changes to crops, grazing regimes and machinery may lead to a loss of groundcover on earthworks, especially on unprotected sites. Data Certainty: Moderate Increased frequency of winter storms and summer droughts may lead to changes in grazing levels as a result of changes in ground moisture. Drier conditions could lead to a reduction in cover of vegetation and wetter conditions may lead to an increase. If they were to become too wet, some sites may no longer be suitable for animals to graze. Both outcomes could have potentially damaging effects. Data Certainty: Low

Sedimentation or erosion

Increases in annual average temperatures may increase soil decomposition rates meaning that in places archaeological deposits may be revealed, leading to their damage or loss. Data Certainty: Moderate
Drought may lead to the reduction in cover of vegetation surrounding features, exposing the earth and making the area more vulnerable to erosion particularly during frequent or heavy rainfall periods. Data Certainty: Moderate

Invasive or other species interactions

Increased levels of atmospheric carbon dioxide and nitrogen may lead to increased growth rates in plants growing on or near sites. Species such as bracken, Japanese knotweed, Himalayan balsam and trees and shrubs have the potential to cause damage to earthworks and may require more management. Data Certainty: Moderate

Populations of burrowing mammals such as badgers, moles and rabbits have the potential to increase if warmer winters mean their natural mortality rate decreases. This could increase damage to buried archaeological deposits and destabilise buried stonework and structures. Data Certainty: Moderate

Other indirect climate change impacts

Hotter and drier summers, coupled with increased visitor numbers are likely to lead to an increase in incidence of wildfire on moorland and grassland. Removal of vegetation resulting from fire may leave the structure and surrounding areas vulnerable to the risk of erosion from animals and weather. Damage may also occur to the monument from the firefighting activity itself. Data Certainty: High

Nutrient changes or environmental contamination

Possible soil chemistry alterations as a result of atmospheric pollution may lead to the damage of ceremonial monuments sensitive to these changes. Data Certainty: Low

What is the adaptive capacity of prehistoric burial mounds and ceremonial monuments?

Overall adaptive capacity rating

Some protection is provided by the Ancient Monuments and Archaeological Areas Act of 1979 for scheduled sites, which can reduce damage and changes to sites caused by farming practices such as ploughing. Unfortunately, this protection is not afforded to undesignated or unknown archaeological sites, and indeed 95% of PDNP heritage assets hold no formal protection. Many of the known barrows and cairns in the PDNP are scheduled, but the PDNPA barrow survey indicates that many are not. At scheduled sites, there is an increased probability of appropriate management actions being implemented to offset climate change impacts. Data Certainty: High

Some funding from sources such as Historic England Management Agreements, the National Lottery Heritage Fund and Environmental Stewardship Agreements is currently available, but is limited. Monuments are likely to have a variable uptake of these funds and the status and designation of sites is likely to affect the amount of funding received. It is more likely that designated sites will obtain funding over undesignated ones. Data Certainty: High

There is a good level of information and skill available to undertake adaptation to at least partially deal with the indirect impacts of climate change through careful management of sites, with bodies such as Historic England and PDNPA providing advice and information. Data Certainty: Moderate

Prehistoric burial mounds and ceremonial monuments and associated archaeological artefacts are an irreplaceable and finite resource, susceptible to damage and loss. However, appropriate protections and management should be able to offset partially the impacts of climate change. Data Certainty: Moderate

Bronze Age sites in the PDNP can be found in a wide variety of locations with different geologies, land uses and habitats. This diversity will provide a degree of protection to the overall resource. However, there is less diversity in known Neolithic sites due the small number discovered, and these are likely to have less adaptive capacity as an overall resource. Data Certainty: Low

Key adaptation recommendations for prehistoric ceremonial monuments:

Improve current condition to increase resilience

The current condition of a feature is an important factor alongside its sensitivity and exposure, in determining its vulnerability to climate change. These recommendations are aimed at improving the condition of the feature at present, therefore making it better able to withstand future changes to climate.

• Create an action plan for recording sites discovered as a result of land use changes and other factors.
• Consider the landscape context of these structures and improve resilience of the surrounding landscape to better protect them.
• Ensure that any climate adaptations can be reversed to prevent long term impacts on features.
• Use sites themselves as valuable assets for example to sustainably generate money for their upkeep. Explore opportunities in future environmental land management schemes.

Improve current condition to increase resilience: Targeted conservation efforts for important sites and at risk areas

The current condition of a feature is an important factor alongside its sensitivity and exposure, in determining its vulnerability to climate change. These recommendations are conservation measures aimed at those sites that will have the biggest impact for this feature – either because they are particularly important for the feature or because they are most at risk from climate change.

• Further exploration into evaluating site significance and evaluating which known assets require protection and management.
• Implement monitoring of sites, especially where adaptations have been made and their surroundings - this may provide beneficial information for other sites. Carry out regular monitoring of scheduled sites.
• Put forward non-scheduled sites of suitable quality for scheduling.