National Character Area 125
South Downs - Natural Capital and Key Ecosystem Services
Introduction
The South 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 South Downs NCA is contained in the ‘Analysis’ section of this website.
Note: The natural capital in this NCA is mapped below. This displays more recent national and publicly available data sets as used within Natural England’s 2020 Natural Capital Atlas Profiles.
The predominant ecosystem services in this NCA are also summarised below. The text contained in this section is based on the previous NCA profiles in 2014, and so is not entirely current. Further information on ecosystem services provided in the North Northumberland Coastal Plain NCA is contained in the Analysis: Ecosystem Services page 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:
- 12: East Sussex
- 17: Hampshire and the Isle of Wight
- 41: West Sussex
Note that numbers and figures in the body of the text are based on the 2014 profiles, unless otherwise stated.
Provisioning services (food, fibre and water supply)
Food provision: The area is a major producer of cereals (including wheat and barley) grown on the dip slope, as well as meat (notably, South Downs lamb from the eastern downs) and dairy produce (from the valleys). These activities are historically important to the downland landscape. Oilseed rape is also a significant crop. There has been an increase in pig husbandry, so although sheep farming is more characteristic within the NCA, livestock farming is more diverse.
Water availability: The chalk hills of the South Downs are the source of all the water for the They act as a natural filter system and storage reservoir, supplying drinking water, irrigation for farms and gardens, and water for industry. In the east of the NCA, the Brighton groundwater management unit is the principal chalk aquifer supplying Brighton and Hove and surrounding areas and is identified as being ‘under significant stress’.(Adur and Ouse Catchment Abstraction Management Strategy, Environment Agency, March 2005, accessed March 2013) In the centre of the NCA, the Worthing chalk aquifer is classed as having ‘no water available’ while the Chichester chalk aquifer is classed as being ‘over-licensed’. (The Arun and Western Streams Catchment Abstraction Management Strategy, Environment Agency, April 2003, accessed March 2013) To the west, groundwater below the chalk hills provides the majority of the water abstracted for public supply. (The East Hampshire Catchment Abstraction Management Strategy, Environment Agency, May 2003, accessed March 2013). 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)
Regulating soil erosion: The lighter soils that dominate the NCA are prone to loss through both wind and water The small areas of soils with impeded drainage are susceptible to capping and slaking, increasing the risk of soil erosion. The thicker, more clayey soils have a low risk of soil erosion (National Soils Resources Institute, Cranfield University).
Regulating soil quality: The shallow lime-rich soils over chalk, covering 63 per cent of the NCA, and the deeper, freely draining lime-rich loamy soils, covering 13 per cent of the area, are typically shallow and prone to drought, but have a degree of natural resilience due to their calcareous Both these soil types and the freely draining slightly acid loamy soils, across 14 per cent of the area, are valuable for aquifer recharge (National Soils Resources Institute, Cranfield University).
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: The River Arun is identified in the Arun and Western Streams Catchment Flood Management Plan as an area of low to moderate flood risk where action should be taken to store water or manage run-off in order to reduce downstream flooding and provide environmental Similar policies are identified for the Adur catchment. The natural landscape also currently buffers a large amount of rainfall and flood plain areas already provide a service by storing vast amounts of floodwater. The flooding in Lewes in October 2000 was the worst in over 150 years. More than 600 homes and over 200 public and commercial premises were affected (Lewes Flood Plan 2010, Lewes District Council and East Sussex County Council, March 2010). A number of targeted actions are proposed to mitigate flooding in this area.
Regulating coastal flooding and erosion: Along the coast, between Eastbourne and Seaford, the Shoreline Management Plan predominantly identifies long- term policies of ‘no active intervention’ for the eastern stretches. At Brighton and Seaford, the long-term policy is to ‘hold the line’, while there are short-term policies of ‘hold the line’ at Peacehaven and Saltdean to maintain cliff-top assets (Shoreline Management Plan 12 ‘Beachy Head to Selsey Bill’, Environment Agency, 2006, accessed March 2013). The plan supports a range of schemes and there are proposals to allow dynamic coastal processes to continue where Allowing natural coastal processes to operate creates new habitats which maintain and enhance local landscape character, biodiversity and geological assets; it also improves the sustainability of current management practices. The coastal habitats mitigate the severity of coastal flood events and rates of coastal erosion, while some erosion is favourable to and necessary for evolution of the coast and to provide sediment for areas further down the coast. 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: Sense of place is provided by the highly distinctive elevated chalk ridge, scarp and dip slopes and numerous dry The dramatic chalk cliffs, defined as Heritage Coast within the South Downs National Park, are particularly distinctive and contrast with the ancient woodlands and parklands in the west. The downs have been a source of inspiration for generations of artists and writers, including Rudyard Kipling, John Constable, Eric Ravilious and the Bloomsbury Group.
Sense of history: The area contains a wealth of visible prehistoric remains, including Neolithic flint mines, bronze-age barrows and prominent hill Historic parklands are prominent within the NCA and Brighton and Hove and the other coastal towns provide a strong sense of history with their distinct architecture and Georgian and Victorian associations. The area’s traditional architecture, in its farmsteads and settlements, is highly distinctive and includes a high proportion of buildings from the 16th century and earlier. Family farms and estates, often centuries old, carry the understanding and knowledge of the countryside’s history which gives meaning to the landscape. Linear parishes and estates reaching up to former grazings from farmland on either side of the downs and numerous lanes that climb and fall from the downs reflect historic land use patterns such as sheep farming.
Tranquillity: A strong sense of tranquillity is associated with the open downland combes and ridges and with the ancient woodland and majestic beech hangers in the They provide a sense of freedom and escape within the highly developed south-east of England.
Recreation: Recreation is a significant feature of the area, with the majority of the NCA falling within the South Downs National Recreation is supported by nearly 2,000 km of rights of way, including the South Downs Way National Trail running along the crest of the scarp slope. More than 4 per cent of the area is open access land (defined as land open to access on foot by the Countryside and Rights of Way Act 2000), mainly areas of open chalk downland
Biodiversity: A total of 4,851 ha of the NCA are designated as Sites of Special Scientific Interest (SSSI); there are seven SAC; and seven The Arun Valley is internationally designated as a Ramsar site and also as an SPA. Just over 3,000 ha of the NCA is considered Biodiversity Action Plan (BAP) priority habitat, including coastal and flood plain grazing marsh, maritime cliff and slope, lowland calcareous grassland, fens, lowland meadows, lowland dry acid grassland, coastal vegetated shingle, reedbeds, mudflats and saline lagoons. The Brighton and Lewes Downs Biosphere covers around 390 square kilometres of land and sea in Sussex, between the Rivers Adur and Ouse. It incorporates a variety of important habitats and species, including chalk grassland, undersea reefs, Adonis Blue butterfly and Short- snouted Seahorse and lies partly within the South Downs National Park.
Geodiversity: The NCA has six geological SSSI, designated variously for geomorphological, structural, karst, stratigraphic, fossil and Quaternary interests. Other local sites are designated as geological The Devil’s Dyke valley is the deepest single combe in the chalk karst of Britain. The cliff coast between Beachy Head and Seaford Head is a GCR site of international importance to research into coastal geomorphology. In certain locations, such as at Lullington Heath, wind-blown soils called loess have been deposited on top of the chalk and are thought to have been laid down during the last ice age.
