119 - North Downs : Natural Capital and Key Ecosystem Services

Introduction

The North Downs NCA provides a wide range of benefits to society. Each is derived from the attributes and processes (both natural and cultural features) within the area. These benefits are known collectively as ‘ecosystem services’. The predominant services are summarised below. Further information on ecosystem services provided in the North Downs NCA is contained in the ‘Analysis’ section of this website.

What is Natural Capital?

Natural capital means “the elements of nature that directly or indirectly produce value to people, including ecosystems, species, freshwater, land, minerals, the air and oceans, as well as natural processes and functions” (Natural Capital Committee, 2017).

It is helpful to consider natural capital in the form of a logic chain that represents the links between ecosystem assets, services, benefits and value to people. The figure below displays that logic chain. The quantity and quality of ecosystem assets (woodland, bogs, etc) support different types of ecosystem services, such as carbon sequestration or water filtration. These ecosystem services then provide different benefits to society, providing value for people. The figure also shows how management interventions, as well as pressures and drivers of change, influence this chain. Other capital inputs are also often needed for people to obtain the benefits from ecosystem services (a simple example is the processing of trees to produce wood products).

As an example, an area of woodland (ecosystem asset) may reduce air pollution created by traffic on a nearby road. This woodland is therefore improving air quality (ecosystem service) in the local area which results in cleaner air and improved health in the adjacent residential street (benefit). This cleaner air has a value because we know it impacts the health and wellbeing of communities.

Sometimes for ease of understanding, economic framing is used to give these benefits a monetary value. The figure below shows how natural capital assets support the provision of ecosystem services, benefits and value. The roots of the tree show how aspects of asset quality are critical to the provision of ecosystem services. The roots also show that geodiversity underpins the ecosystem assets and therefore the ecosystem services and benefits they can provide. It is important to remember that this diagram, and natural capital frameworks more generally, are a simplification of how nature works in practice.

Natural Capital within this NCA

In 2018, Natural England published ‘Natural Capital Indicators: for defining and measuring change in natural capital’ (Lusardi et al., 2018). This report identified key properties of the natural environment vital for the long-term sustainability of benefits, which can act as indicators of change.

These indicators are designed to inform our understanding of the state of our natural assets. The indicators highlight the importance of our natural assets for delivering which ecosystem service and the benefits they provide for society. The indicators and datasets identified in Natural England’s Natural Capital Indicators Project provide the foundation for the Natural Capital Atlas Profiles.

Natural England’s Natural Capital Atlas Profiles provide an “off the shelf” natural capital evidence base for each county or city region. They have a wide variety of uses with more information in the How to Start Using Your Natural Capital Atlas.

The Natural Capital indicators are presented on the map below by broad asset theme, displaying the natural capital within the NCA.

It is noted that not all indicators listed within the Natural Capital Atlas Profiles are included within the map as data is not yet available to measure them. Refer to the “Indicator Gaps and Limitations” of the Natural Capital Atlas Profiles for further information.

Natural Capital Atlas Profiles

The following Natural Capital Atlas Profiles cover counties within this NCA:
 

• 15: Greater London
• 20: Kent
• 37: Surrey

Provisioning services (food, fibre and water supply)

Food provision: The NCA is a significant producer of beef, lamb, wheat and oilseed and also retains over 1,000 ha under fruit; the majority of orchard crops are now grown from dwarf varieties rather than traditional standard trees. More recently, there has been an increase in novel crops, for example viticulture.

Timber provision: The existing resource provides good opportunities for timber production with over 25,000 ha of woodlands covering 19 per cent of the NCA. A significant unused or underutilised resource is the large areas of sweet chestnut coppice in the Kent part of this NCA.

Biomass energy: A very considerable potential biomass resource resides in the area covered by woodlands that are largely unmanaged and could be brought back under management. This includes the areas of derelict sweet chestnut coppice and areas of ancient woodland that were traditionally managed under a coppice regime.

Water availability: The chalk bedrock is a principal aquifer. In Kent, 73 per cent of public water is taken from groundwater, although this figure is likely to be even higher for the North Downs area, most notably from the chalk aquifer underlying this NCA (The State of Water in Kent, Environment Agency, 2012). All of this aquifer is already considered to be of poor quantitative status (Annex A, Current State of Waters, Thames and South East River Basin Management Plans). The abstraction pressure on water supplies is considered by the Environment Agency to pose a risk to seasonal low river flows in much of the area, including the Darent and Middle Stour. Due to the underlying geology the area is cut by relatively few rivers (the Great Stour in the east, Medway and Darent in the centre and Mole and Wey in the west). Watercourses also flow seasonally as winterbournes. For information regarding the current state of water availability within this NCA, refer to the Environment Agency (Abstraction Licensing Strategy).

Regulating services (water purification, air quality maintenance and climate regulation)

Climate regulation: The woodlands and soils of the NCA are important stores of atmospheric carbon, as to a limited extent are the valley wetlands and areas of remnant heath (Carbon storage by habitat: Review of the evidence of the impacts of management decisions and condition of carbon stores and sources, Natural England, 2012). The woodland resource is particularly important for climate regulation in terms of adaptation and mitigation. Given the extent of arable farming, low carbon arable production could also be important throughout the NCA.

Regulating soil erosion: The majority of soils within the area are shallow chalky or deeper loamy soils prone to erosion, particularly on the steeper slopes. Given the extent of cultivated land, this is an important service, having knock-on effects; for example, soil erosion from slopes within river catchments contributes to deterioration in the water quality of the area’s rivers, including the Defra priority catchment of the Great Stour.

Regulating water quality:For information regarding the current state of water quality within this NCA, refer to the Environment Agency (Draft river basin management plan maps).

Regulating water flow: Flooding is a localised issue along stretches of the NCA’s rivers, in particular the River Medway in the east, with recent flooding affecting both Maidstone and Chatham (Medway Strategic Flood Risk Assessment, Medway Council, 2006) (through a combination of surface water, fluvial and tidal flooding), and the River Wey in the west, with a history of significant flooding affecting Guildford (Environment Agency Flood Risk Map). Flooding of the Stour affects Canterbury to the north of the NCA. Potential exists to increase the storage of water along the flood plain of the Stour within the NCA itself to help to alleviate downstream flooding as well as to enhance the important wetland environment. This also applies along the Darent, while flooding on the River Mole can be alleviated by maintaining the existing capacity of the river and flood plain (Stour, North Kent Rivers and Thames Catchment Flood Management Plans,
Environment Agency, 2009)

Regulating coastal flooding and erosion: The coastline between Folkestone and Deal is relatively high and as a result inundation is not a significant issue, but more relevant are coastal erosion and rate of erosion, which could lead to the loss of cliff-top habitats. The Shoreline Management Plans have proposed policies of ‘No Active Intervention’ where possible to allow for natural regeneration of the cliffs and thus maintenance of the geological and wildlife interest. Maintenance of existing flood defences is identified around areas of important development, such as Dover’s Channel Tunnel infrastructure and Deal in the north. For information regarding current shoreline management within this NCA, refer to the Environment Agency (Shoreline management plans).

Cultural services (inspiration, education and wellbeing)

Sense of place/inspiration: The North Downs have been a source of inspiration throughout the centuries. The dramatic landscape which terminates at the famous White Cliffs of Dover is much cherished and the two AONB designations and the Heritage Coastline are a testament to the natural beauty afforded by this predominantly chalk landscape. The NCA has inspired the life and work of various famous individuals including Charles Darwin, Winston Churchill, Samuel Palmer, Henry Moore and Jane Austen. The image and perception of the White Cliffs of Dover make them an iconic feature and they have close associations with our military history, representing strength and defence. It is not only the more obvious dramatic features of the scarp and cliffs that provide a sense of place, but also the intricate mosaic of habitats, sunken lanes and droves, parklands and other historic features and buildings which overlay the underlying geology, together making this NCA both unique and inspiring.

Sense of history: The NCA has a strong sense of history from Neolithic monuments, bronze-age barrows, iron-age hill forts, Roman villas and towns, ancient routeways, medieval villages, and post-medieval stately homes with their associated parks and gardens. Historic defence structures span from Norman times to the 20th century and today the White Cliffs of Dover and Dover Castle are still perceived to have strong associations with military history. Equally, the geology of the chalk cliffs provides a sense of the Earth’s history – the laying down of the bedrock and the movement of land masses.

Tranquillity: The landscape is highly developed along its boundaries and therefore can lack a sense of remoteness, but the areas of extensive woodland cover and farmland offer tranquillity and calm even where development is present. According to the Campaign to Protect Rural England Intrusion Map (2007), per cent of this NCA is developed, 60 per cent disturbed and 29 per cent undisturbed.

Recreation: The landscape offers significant opportunities for leisure and recreation with good access for walking and gentle heights and upland areas. It is traversed by both the North Downs Way National Trail, largely following the chalk scarp, and the Pilgrims’ Way long-distance route. This is supported by a relatively dense rights of way network, particularly within the two AONB, as well as more than 3,500 ha of open access land, accessible parkland, country parks and National Nature Reserves. This is of particular importance given the proximity of the North Downs to large centres of population. These recreational opportunities offer benefits to physical and mental health and to local economies.

Biodiversity The NCA includes a range of priority habitats including lowland mixed deciduous woodland, lowland calcareous grassland, lowland beech and yew woodland, and lowland heathland. Much of the woodland is ancient. These provide a genetic resource, comprising nine SAC covering over 1,500 ha, with a significant proportion relating to calcareous grassland, and 51 Sites of Special Scientific Interest, covering over 5000 ha. The NCA is renowned as the home of some of the richest chalk grassland plant communities within the British Isles; the influence of a continental climate provides the conditions for a range of flora and fauna on the edge of the northern and western ranges, including the lady orchid and late spider orchid, which have their stronghold in this NCA.

Geodiversity: The White Cliffs of Dover are one of England’s most distinctive landmarks and an area of international importance. The Chalk exposed along this coast is critical to our understanding of Chalk sequences across Europe and understanding the landslips at Folkestone Warren helps us understand how similar landslips work around the world. Inland the mix of disused chalk quarries and pits provide critical evidence of our geological past. Many are now identified as geological SSSI and Local Geological Sites, for example Britain’s most prolific source of Chalk (Upper Cretaceous) marine vertebrates including fish, turtles, marine lizards, pliosaurs and plesiosaurs come from chalk pits near Bulham. Similarly, the network of dry valleys and features such as the Devil’s Kneading Trough and their associated sediments are critical in interpreting the more recent environmental changes of the Quaternary Period.