120 - Wealden Greensand : Natural Capital and Key Ecosystem Services

Introduction

The Wealden Greensand 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 Wealden Greensand 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:
 

• 17: Hampshire and the Isle of Wight
• 20: Kent
• 37: Surrey
• 41: West Sussex

Provisioning services (food, fibre and water supply)

Food provision: An area of mixed farming that produces significant amounts of cereals and other arable crops. Also livestock, including sheep, pigs and cattle, and notably fruit growing and other horticultural crops – particularly in Kent. Includes some of the most productive agricultural land in Kent, where the ridge is less pronounced and the soils are more fertile.

Biomass energy: The existing woodland cover (25 per cent of the NCA) offers significant potential for the provision of biomass through bringing unmanaged woodland under management. The NCA has been identified as having a high potential yield for sweet chestnut coppice, while short rotation coppice is generally medium: central areas around Redhill and Reigate, where lighter loams occur, have been identified as being more suitable (Energy crop guidance and yield maps).

Water availability: The majority of the area overlies post-Carboniferous rock (a sandstone aquifer), with a small area in the west overlying a chalk aquifer. For the area of strata assessed, the quantitative status is considered to be poor (Thames River Basin Management Plan, Environment Agency, 2009) and (South East River Basin Management Plan, Environment Agency, 2009). Water availability in both surface waters and the aquifer is under pressure from existing abstractions for public water supply and (to a lesser extent) for industrial and agricultural supply. The Lower Greensand aquifer supports surface water flows and provides base flow to the internationally important wildlife sites of the Arun Valley – SPA, SAC, Ramsar and heathland sites that have water-dependent habitats. The aquifer has an important role in maintaining spring and base flows of rivers; any low flows may damage the ecology of rivers and wetlands. 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 very acidic sandy and loamy soils include some thin, organic and peaty topsoils that are a store of carbon, associated with the area’s remnant heathland habitats. Some of the loamy and clayey flood plain soils are peaty at depth, or include small areas of peaty soils. The woodlands of the NCA also play an important role in climate regulation. However, as many of the soils are droughty sands and coarse loams they generally have a low organic matter content, which could be enhanced by organic matter inputs.

Regulating soil erosion: Freely draining, loamy and/or sandy soils make up 60 per cent of the NCA, and generally carry an enhanced risk of soil erosion on moderately or steeply sloping land where cultivated or bare soil is exposed. This is often exacerbated where organic matter levels are low after continuous arable cultivation, or where soils are compacted. Wind erosion can also be an issue for many of these soils. The freely draining, sands, silts and coarse loam soils, can be at risk of increased erosion. Loamy and Clayey soils with impeded drainage can be prone to both capping and slaking, and are easily compacted by machinery or livestock if accessed when wet, increasing the risks of soil erosion by surface water run-off. In the south-west of the NCA, steeper sandy soils under arable cultivation are highly prone to erosion.

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 has been an issue within the NCA and the river catchments more widely. Land adjacent to both the Mole and Wey has been subject to significant flooding in the past, including flooding of urban areas along their course. Most notable is the very significant flooding of Godalming (in the Wealden Greensand) and Guildford (in the adjacent Thames Basin Lowlands NCA) on the course of the Wey in 1968. Guildford, although outside the NCA, is an area of high risk along the River Wey. Flood plain management in the wider catchment is identified as being a key mitigation measure. Maidstone is identified as an area of moderate risk along the River Medway (River Medway Catchment Flood Management Plan, Environment Agency, 2009). Ashford is identified as being at risk from flooding and this risk is likely to increase as a result of climate change.

Regulating coastal flooding and erosion: Long-term ‘Hold the Line’ policies are identified within the Shoreline Management Plan along the relatively small stretch of developed coastline that falls within the NCA between Folkestone and Hythe. The exception of Copt Point (where a policy of no active intervention is applied) will allow the undeveloped cliffs to erode, maintaining their environmental and geological value. For the rest of the stretch, preferred policies of ‘Hold the Line’ protect buildings, infrastructure and amenities. Identified implications are the narrowing of the intertidal area as a result of sea level rises, with the subsequent loss of fronting beaches – which are an important asset to tourism within the area – as well as a reduction in the long term in the amount of sediment available for downdrift frontages (South Foreland to Beachy Head Shoreline Management Plan, Environment Agency, 2006).

Cultural services (inspiration, education and wellbeing)

Sense of place/inspiration: A sense of place is provided by the prominent Greensand ridge, which affords many far-reaching views over the Low Weald from the scarp top, as well as by the extremely varied landscape character – a result of the diverse underlying soils and geology, and the overlying land use. Also distinctive are the extensive areas of lowland heathland (in Surrey, Hampshire and Sussex) and ancient woodland, which include the distinctive hanger woodlands found on steeper slopes (notably in East Hampshire) and the wooded commons or charts characteristic of East Surrey and West Kent. Rivers draining the dip slope (and their associated wetland habitats) further support this varied character, as do the irregularly-patterned fields bounded by hedgerows and shaws, and the traditional fruit-growing areas of Kent. The rural settlement pattern of dispersed farmsteads, hamlets, some nucleated villages and tree-lined, sunken lanes adds to the distinctive sense of intimacy within the landscape in the south-west.

Sense of history: The history of this landscape is evident in the predominantly irregularly-patterned fields and in the ancient road network, as well as in the area’s prehistoric associations: including bronze-age tumuli near Petersfield and on the higher ground of heathlands in Sussex, iron-age hill forts at Holmbury, Anstiebury and Oldbury Hill, and Neolithic remains at Abinger. Aspects of history that are particularly striking in the landscape are the numerous large houses and designed parklands, including Petworth in Sussex, Knole, and Leeds Castle in Kent, and the traditional vernacular of local sandstone and patterned dark carrstone (known as ‘galleting’) – most notably in Surrey. The hammer ponds associated with iron workings along the foot of the north-west escarpment contribute to the sense of history and provide links with the area’s industrial heritage.

Tranquillity: Twenty-seven per cent of the NCA is classified as ‘undisturbed’ according to CPRE data, a decline from over 60 per cent in the 1960s. Tranquillity is most generally associated with the intimate rural landscape of the south-west (much of which falls within the South Downs National Park), in contrast with the more heavily developed eastern and central areas. Tranquillity is nevertheless likely to be associated with the extensive chain of heathlands and ancient woodlands that occur throughout East Hampshire, Surrey and West Kent: these remaining areas of tranquillity are important where development pressures are so high.

Recreation: Recreation and access are supported by 3,315 km of public rights of way, including links to both the North Downs Way and South Downs Way national trails, as well as over 6,700 ha of open access land – around 5 per cent of the NCA. Part of the area to the south-west falls within the South Downs National Park, which seeks to offer wide- ranging opportunities for countryside recreation and access (The South Downs Management Plan, 2008-2013, South Downs Joint Committee, 2008). The Surrey Hills AONB and Kent Downs AONB also have much to offer in terms of recreation within inspiring landscapes. The woodland and heathland landscapes of Surrey and West Kent are particularly important for access, given their proximity to London and other significant urban areas, and also given increasing pressure for public recreation – particularly cycling and walking. The coastline offers a further recreational resource, as do the NCA’s rivers – some of which are navigable, and are host to a range of water-based activities. These recreational opportunities offer benefits to physical and mental health, and to local economies, but there is a need to manage their impact on sensitive sites, where the ecology of these areas is at risk from significant footfall or from potentially damaging activities.

Biodiversity: The NCA supports a variety of habitats and species. There are over 26,500 ha of Biodiversity Action Plan (BAP) priority habitat, covering around 18 per cent of the NCA. This includes lowland woodland (lowland mixed deciduous woodland (5,628 ha) and lowland beech and yew woodland (2,713 ha); lowland heathland (5,557 ha) and wetland fens (3,518ha); wet woodland (2,936 ha); and coastal and flood plain grazing marsh (1,302 ha). The NCA has a number of international designations, with three SPAs, ten SAC and two Ramsar sites, indicating the area’s contribution to international biodiversity.

Geodiversity: The geodiversity of the Wealden Greensand NCA is of great importance. There are 18 SSSIs designated for their geology and 27 Local Geological Sites encompassing Cretaceous and Pleistocene geology, including classic exposures of Lower Greensand, Gault Clay, windblown sands or loess, and landslip features. Disused quarries and road cuttings are particularly important, as are the dramatic coastal sections of Folkestone Warren. The ridge itself gives spectacular views across the Low Weald, and Leith Hill is the highest point in Surrey. Key landscape features include the Devil’s Punch Bowl at Hindhead and the Lympne Escarpment on the boundary with the Romney Marshes. As well as being of great importance in its own right, the geology is of fundamental importance to biodiversity. The complexity of the geology and soils has led to great variation in the vegetation that it supports. There are also clear links between traditional building materials and industries, which have been supported by the local geology; for example, ironstone was important in early iron production in the area.