124 - Pevensey Levels : Natural Capital and Key Ecosystem Services

Introduction

The Pevensey Levels 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 Pevensey Levels 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:
 

• 12: East Sussex

Provisioning services (food, fibre and water supply)

Food provision: 83 per cent of the area is under pasture or is uncropped. This supports the principal food producing activity: livestock farming. Around half of farms are engaged in livestock farming including beef cattle, dairy and sheep. Significant amounts of arable land have been converted to pasture relatively recently under agri-environment schemes. Much of the produce is high quality and low intensity with many organic farms and low stock numbers. There are a few surviving orchards.

Water availability: Part of the South Downs chalk aquifer lies under the eastern edge of the NCA. The main river is Waller’s Haven which, with upstream abstraction, provides the water supply for Bexhill, but most of the water supply for the area’s population comes from Arlington Reservoir and the Cuckmere catchment (outside the NCA).

Summer water levels on the Pevensey Levels are maintained by the operation of 37 main feed sluices, which provides water to about 60 per cent of the area, and there are a number of other structures and pumping stations across the NCA (Pevensey Levels SSSI Water Level Management Plan, Environment Agency, 2006).

The eastern and western sides of the Pevensey Levels SSSI are hydrologically distinct. Substantial flows from wastewater treatment works at Hailsham maintain levels in the western river system in summer and much of the area remains wet throughout the year. Eastern areas can be fed from Waller’s Haven. Summer flows into the eastern system are naturally lower and are complicated by the major south-east water abstraction at Hazards Green.

The present water level management plan aims to keep water levels constant (about half a metre below ditch shoulder) all year round. 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 undisturbed soils of the coastal and flood plain grazing marsh (36 per cent of the NCA) and the wet loamy soils offer a significant carbon storage resource and future carbon storage capacity. High carbon levels may also be associated with the soils of the coastal flats where some variants may have organic-rich topsoils.

Regulating soil erosion: Soil erosion is recognised as a problem within the Defra catchment sensitive farming priority catchment in the area. Parts suffer from damaged soil structure, notably compaction and impeded drainage in areas with clay soils, which accelerates run-off. This leads to increased erosion rates and sedimentation of watercourses.

Regulating soil quality: Loamy and clayey soils (54 per cent of the NCA) are at risk from topsoil compaction and poaching. Careful management of weak topsoils will help to maintain a good soil structure. Minimum tillage such as direct drilling can work well in some of these soils. Where organic matter is low increasing inputs can help to improve soil structure.

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 hydrology of this low-lying, flat area is dominated by the dynamics of the relationship between stream inflow, rainfall, outflow to the sea and evapotranspiration. The significance of groundwater movement is lessened by a layer of clay which effectively isolates the Levels from the underlying chalk aquifer. Water flow on the Levels is regulated by the water level management plan (Pevensey Levels SSSI Water Level Management Plan, Environment Agency, 2006) which aims to keep water levels constant (about half a metre below ditch shoulder) all year round. Levels are controlled by a series of sluices and pumping stations.

Since the early 1990s, a mechanism has been in place whereby the effects of development on flood levels has been compensated for by the creation of additional flood storage (lakes) in Eastbourne Park (Eastbourne Council).

Regulating coastal flooding and erosion: Regulating coastal flooding and erosion: Littoral processes along the coastline are extremely dynamic. Both erosion and accretion have been instrumental in the configuration of the coast. There is a large continuity of long-shore drift, with eastward transport of sand and shingle owing to the influence of wave diffraction patterns.

Shoreline Management Plans (Shoreline Management Plans – South Foreland to Beachy Head, South East Coastal Group, 2006) for the area promote a ‘Hold the Line’ policy for the entire coast in the face of predicted sea level rises. To achieve this, much of the unique shingle beach may be lost.

The ditches and grazing marshes of the Levels also provide an additional flood defence line for inland areas.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 open, windswept landscape inspires some of the most intense feelings of remoteness in south-east England, providing a retreat from the bustling urban centres of Eastbourne and Bexhill. The Pevensey Levels have a strong sense of a landscape reclaimed from and facing towards the sea.

Eric Ravilious lived in Eastbourne and often used local scenes for inspiration. The Towner Art Gallery in Eastbourne has a large collection of his work. Debussy completed his masterpiece La Mer in Eastbourne in 1905 and the coastal views remain a source of inspiration for modern artists.

Sense of history: Pevensey Castle dominates the landscape and there are many important sites on the Levels including deserted medieval villages and relics of the salt making industry. The area is rich in evidence of its strategic military importance, including Napoleonic Martello towers.

More recent coastal development tends to reflect the increased popularity of the seaside. Eastbourne retains its essentially Victorian seafront including a fine Grade II* pier, while the style of Pevensey’s 1950s weather-boarded seaside housing creates a jaunty resort atmosphere.

The entire landscape of the Levels maps the reclamation work started by local religious houses in the Middle Ages and there are rare examples of lowland medieval field patterns.

Tranquillity: The quiet, simple landscape of the Levels provides a tranquil and relatively undisturbed buffer between the busy urban centres of Eastbourne and Bexhill. The close association with waterbodies and watercourses further accentuates the sense of tranquillity and there are also peaceful areas along the coast, away from popular tourist hotspots such as Eastbourne and Pevensey Bay.

Recreation: Tourism is an important industry along the entire coastline of the NCA with the seaside resort of Eastbourne and caravan parks around the edges of the Levels.

Walking and horse riding occur on the many footpaths and bridleways. The start of the South Downs Way National Trail is just outside the NCA on the edge of Eastbourne. The flat, scenic landscape also makes it popular with cyclists and National Cycle Route 21 starts and ends in Pevensey.

The large main drainage channels on the Pevensey Levels support an important coarse fishery and all the havens are used for angling. There is also a golf course within the SSSI. The National Nature Reserve has limited public access owing to the fragile ecology but guided tours are offered.

The Eastbourne Health Improvement Partnership identified ‘Promotion of Healthy Lifestyles’ as one of three local priorities in 2005. More than half of Eastbourne residents say that they visit natural areas such as beaches, parks and downland at least once a month, mostly for recreation such as a ‘gentle walk’, ‘active leisure’ and ‘informal sport’ (Health Improvement & Modernisation Programme 2003 to 2005, Eastbourne Health Improvement Partnership)

Biodiversity: Pevensey Levels is one of the most important wetland sites in south-east England. The 3,500 ha SSSI, Ramsar and former Important Bird Area supports a variety of wetland flora and fauna, including rarities such as the fen raft spider (Birdlife). Numbers of wading birds severely declined after the introduction of pump drainage systems in the 1960s, although these are starting to return owing to recent improvements such as the water level management plan and agri-environment schemes on the land.

The ditches in the SSSI feature 70 per cent of native aquatic plants.

Pevensey Levels was found to be one of the most important sites in Sussex for yellow wagtails, with 19 pairs recorded in 2008 (Breeding Waders of Wet Meadows Survey).

Eastbourne Park attracts a diverse fauna of freshwater snails, water beetles, dragonflies and damselflies. Breeding birds include lapwing, reed bunting and reed and sedge warbler.

The Dutch Elm Disease Control Zone extends from Westham to Hove. Bounded by the sea to the south and the largely treeless South Downs to the west, the Eastbourne area has maintained much of its mature elm population and the geography and vigilance of authorities may also help with the control of new pests and diseases.

Geodiversity: Soils and soil formation and coastal and river geomorphological processes are key elements of this NCA.