Prehistoric and Romano-British settlements, field systems and cairnfields

Overall vulnerability

Feature(s) assessed:

• Prehistoric and Romano-British settlements, field systems and cairnfields

Special qualities:

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

Feature description:

Prehistoric and Romano-British settlements, field systems and cairnfields give us an insight into what life and agriculture were like in the distant past. These archaeological features have been revealed through the National Mapping Programme (NMP) and extensive archaeological survey over decades within the PDNP. Arable cultivation, particularly in areas with free-draining soils, has revealed pre-medieval settlements and land uses. The PDNPA has completed a large amount of survey work to discover further examples of these archaeological features. This includes 36 records of prehistoric settlements, 36 records of Romano-British settlements, and 65 records of prehistoric cairnfields. In Northern England some of the largest and best preserved prehistoric settlement, field system and cairnfield sites are found on the Eastern Moors of the PDNP.

How vulnerable are prehistoric and Romano-British settlements, field systems and cairnfields?

Prehistoric and Romano-British settlements, field systems and cairnfields in the PDNP have been rated ‘moderate’ on our vulnerability scale. This score is due to moderate sensitivity and exposure to climate change variables, coupled with a varying current condition, and a moderate adaptive capacity.

The current condition of all features is unknown as many have yet to be discovered, but of those that are known only 13% are in poor condition. Sites may be vulnerable to climate change following changes in farming practices, direct erosion and erosion of the soils around the features, and further growth of nuisance plant species. There are appropriate management and conservation actions to help these features adapt to climate change, however it is expected that a significant proportion of these sites have not been formally designated and therefore adaptations are less likely be put in place.

Current condition:

Of the sites that the PDNPA has noted, detailed above, 16% have been excavated and 23% are of uncertain provenance or function. 13% have been damaged, destroyed or lost. Thus far, human activities have had the most significant detrimental impact on these features. Farmers and landowners have often destroyed or damaged sites if their significance was not recognised. The ploughing of fields in recent centuries has led to the destruction of this surface evidence of human activity.

Past changes in climate have helped to protect some sites from human interference. Upland settlements which were abandoned when the climate became inhospitable may not been intensively farmed since and archaeological evidence has therefore survived.

Growth of nuisance and invasive species and animal burrowing have already had harmful effects on some prehistoric and Romano-British settlements, field systems and cairnfields. At time of writing, the Heritage at Risk register shows there are two ‘at risk’ sites in the PDNP. One is the Callow prehistoric settlement and field system on Carr Head Moor where bracken, scrub and trees are putting the feature at risk due to under grazing. The North Lees Countryside Stewardship Scheme is now addressing this. The other ‘at risk’ site is Cowell Flat, which is a prehistoric field system that faces similar plant growth issues. Other similar sites in the PDNP are known to face the same problem.

What are the potential impacts of climate change?

Overall potential impact rating

Direct impacts of climate change

Most impacts from climate change affect prehistoric and Romano-British settlements, field systems and cairnfields indirectly. Directly, precipitation patterns and temperature may have an impact through erosion of the features. Exposed structures may become damaged or weakened due to changes in the wetting and drying cycle or an increase in hydraulic action Data Certainty: High. Structures affected by thermal expansion may be damaged by greater extremes of temperature, causing accelerated erosion of these features. Data Certainty: Moderate

Human behaviour change

Human responses to climate changes are expected to have the biggest impact on these features in the future. There may be landscape use changes as a result of climate change such as more intensive farming, the use of deep-rooted energy crops, establishment of woodlands, and new building developments. This may put prehistoric settlements and field systems at risk. Changes to how moorlands are managed will also affect these sites which are often on the lower moorland ledges. Rewilding could pose a particular threat. Data Certainty: Moderate

An increased frequency of winter storm and summer drought events may result in changes to ground cover. This is because use and management of sites, irrigation and drainage practice, and farming practices may all change. Data Certainty: Moderate

The difference in vegetation cover could lead to changes in grazing levels. If the ground became drier then vegetation cover may decrease and grazing could be reduced, and grazing could increase if the ground was wetter and there was more vegetation growth. Grazing would only increase up to a point however, if it was too wet then animals would have to be removed. Both outcomes are potentially damaging to these features, either directly or resulting in uncontrolled vegetation growth. Data Certainty: Moderate

A change in ground conditions could also encourage new crops to be grown. This could cause, or could happen alongside, a drying of waterlogged environments such as peat soils. Peat soils may dry out and become oxidised causing the loss of historic field patterns. Data Certainty: Moderate

Where excavations are taking place, an increase in storm and flood events may cause delays and therefore damage of these exposed sites. This is especially the case on clay and other slow draining geologies. Data Certainty: High

Hotter, drier summers are likely to attract more visitors to the PDNP. This may cause damage to these features through increased erosion from footfall. Data Certainty: Moderate

Land use changes as described above may lead to new sites being revealed which could benefit these features or put them at risk. If the locations of the features are known then protections can be put in place decreasing the chances of future accidental damage. However, features may be damaged during discovery and not subsequently reported and recorded appropriately. Data Certainty: Moderate

Hotter, drier summers resulting in droughts may provide opportunities for new discoveries in ways that help to protect these features. Marks can appear in crops or as parch marks or lusher growth in grass, highlighting where buried stone walls, foundations or deeper, moisture-retaining ditches are located underground. This occurs because the soil has a different depth or quality over the buried remains, causing patterns to appear on the surface. This helps to discover new heritage assets that can be mapped without damaging the sites themselves. Data Certainty: High

Invasive or other species interactions

Warmer, wetter winters and hotter, drier summers may result in higher populations of burrowing animals such as badgers, moles and rabbits. They may also increase the growth of nuisance species such as bracken and deep rooted plants. This can damage or completely destroy evidence of prehistoric settlements and field systems. There has already been evidence of this at Cowell Flat and Carr Head Moor as described above in ‘Current Condition’. Data Certainty: High

Nutrient changes or environmental contamination

Atmospheric pollution may damage settlements and field systems located at sites sensitive to soil chemistry changes. Data Certainty: Low Soil chemistry could also be changed due to increased incidences of drought, fire and flooding, potentially damaging sites further. Data Certainty: Moderate

Sedimentation or erosion

Drought, fire and flooding increases could lead to erosion occurring. This erosion could cause direct damage as referenced above in ‘Direct’ or could cause erosion of the area around these features, causing structural damage to features such as field banks and other archaeological remains. Data Certainty: Moderate

What is the adaptive capacity of prehistoric settlements and field systems?

Overall adaptive capacity rating

The known field systems and cairnfields are protected by designation under the Ancient Monuments and Archaeological Areas Act of 1979, which aims to prevent damage occurring from farming practices and other activities. Existing practices, at the time of scheduling, are sometimes allowed to continue. This protection does not apply to 95% of the PDNP heritage assets as they are non-designated and unknown sites. The PDNPA is aiming to identify and access sites of these archaeological resources so their significance can be recognised and measures put in place to protect them. Examples of the most vulnerable designated sites can be found on the Heritage at Risk register, but many more vulnerable sites are not included. Data Certainty: High

At scheduled sites, management actions are more likely to be put in place. These may be able to partly offset damage from climate change stressors. The status and designation of a site should help determine the management techniques to be put in place. Designated sites may be more likely to receive funding and appropriate management, which leaves undesignated sites more vulnerable. Funding may include Historic England Management Agreements, Countryside Stewardship and the National Heritage Lottery Fund. However, access to these funding options is limited and the uptake on private land is likely to be variable. Data Certainty: High

Prehistoric and Romano-British settlements, field systems and cairnfields are not able to ‘recover’ by themselves and cannot regenerate. They are a finite resource vulnerable to loss and damage. There are appropriate management and conservation actions that can help these features and the PDNPA and Historic England provide advice regarding appropriate adaptation actions. Data Certainty: Moderate

In the PDNP, there are a large number of prehistoric settlements, field systems and cairnfields found in locations with different geologies, habitats and land uses. This diversity in location helps to spread the risk of damage from climate change. Data Certainty: Moderate

Key adaptation recommendations for prehistoric and Romano-British settlements, field systems and cairnfields:

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.

• Continue to stabilise peat and soils to prevent erosion.
• Continue assessing site significance in order to increase knowledge of asset existence to determine which need protecting.
• Facilitate data sharing information between organisations that helps us understand the extent of archaeological features. This will help inform future adaptation planning.
• Use sites themselves as valuable assets for example to sustainably generate money for their upkeep. Explore opportunities in future environmental land management schemes.
• Ensure that any climate adaptations can be reversed to prevent long term impacts on features.

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.

• Carry out regular monitoring of scheduled sites.
• Put forward non-scheduled sites of suitable quality for scheduling.
• Consider locations of important prehistoric and Romano-British settlements, field systems and cairnfield sites when planning flood management, tree establishment, or piloting wilding trial schemes.
• Monitor outcomes of any adaptations that are implemented.