National Character Area 110

Chilterns - Analysis: Ecosystem Services

Analysis supporting Statements of Environmental Opportunity

The following analysis section focuses on a selection of the key provisioning, regulating and cultural ecosystem goods and services for this NCA. These are underpinned by supporting services such as photosynthesis, nutrient cycling, soil formation and evapo-transpiration. Supporting services perform an essential role in ensuring the availability of all ecosystem services.

Bodiversity and geodiversity are crucial in supporting the full range of ecosystem services provided by this landscape. Wildlife and geologically-rich landscapes are also of cultural value and are included in this section of the analysis. This analysis shows the projected impact of Statements of Environmental Opportunity on the value of nominated ecosystem services within this landscape.

Further analysis on landscape attributes and opportunities for this NCA is contained in the Analysis: Landscape Attributes & Opportunities section.

Natural Capital

Further information on Natural Capital within this NCA is contained in the Natural Capital and Key Ecosystem Services section.

The Chilterns 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 realised through the ‘ecosystem services’ that flow from the ‘ecosystem assets’ or ‘natural capital’ of a place.

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).

Ecosystem Services Main Beneficiaries

The below map displays the main beneficiaries of each ecosystem service identified within this NCA and neighbouring NCAs. These range from being of international importance to local importance. Some services have not been assessed within all NCAs, and therefore in some NCAs are displayed as “N/A” (not applicable).

 

Main Beneficiaries Map

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Ecosystem service analysis

The following sections show the analysis used to determine key Ecosystem Service opportunities within the area. These opportunities have been combined with the analysis of landscape opportunities to create Statements of Environmental Opportunity. Please note that the following analysis is based upon available data and current understanding of ecosystem services. It does not represent a comprehensive local assessment. Quality and quantity of data for each service is variable locally and many of the services listed are not yet fully researched or understood. Therefore analysis and opportunities may change upon publication of further evidence and better understanding of the inter-relationship between services at a local level.

Note that numbers and figures in the body of the text are based on the 2014 profiles, unless otherwise stated.

Provisioning Services

Food provision

Assets/attributes: main contributors to service

  • Soils, particularly Grade 1 and 2 land
  • Arable farming
  • Livestock production
  • Aquifer Grassland

State -Approximately two thirds of the area is described as having Grade 3 land. There are significant areas of Grade 1 and 2 land on valley floors and along the foot of the scarp.

Cereal production accounted for 40 per cent of farmed area, almost the equivalent area, 37 per cent, was grass or uncropped land (Agricultural Census, Department for Environment, Food and Rural Affairs, 2010). Farming is less mixed in Hertfordshire where arable dominates (Land Cover Map, Centre for Ecology and Hydrology, 2000). In the Chilterns AONB, a 2008 survey found wheat growing on 50 per cent of cropped land; barley on 20 per cent and oilseed rape on 11 per cent (Chilterns AONB Land Use Survey 2008, Chilterns Conservation Board, 2008).

Main beneficiary – National

Analysis – Soils on Grade 3 agricultural land are suited to both cereals and livestock farming, hence the mixed farmed landscape. However, ongoing declines in sheep numbers reduce the capacity for local farming systems to sustain the traditional grazed downlands.

The steep slopes of the scarp and valleys (often Grade 4 land) are difficult to cultivate. However, cultivated sloping land with shallow chalk soils are at risk of erosion.. Steep slopes under permanent pasture reap benefits for regulating soil erosion, for biodiversity and sense of place.

Grade 1 and 2 land accounts for about 10 per cent of the NCA and is the most highly versatile, often growing high value arable crops.

Despite the history of sheep grazing on the downlands, the Chilterns is not associated with any traditional rare breeds and there are also no locality foods recognised at a regional or national level (Exploration of the Relationship between Locality Foods and Landscape Character, C. Trewin and L. Mason, 2006; Land Use Consultants).

Orchards are an important feature in the landscape, but are largely relict.

Arable and vegetable production occasionally requires abstractions from groundwater and surface waters, sometimes to provide for spray irrigation.

Climate change may encourage the expansion of vineyards in the Chilterns.

Opportunities – With approximately 10 million people living within an hour’s travelling time of the Chilterns (including London), there are opportunities to build consumer markets around locality foods and rare livestock breeds linked to farming systems that conserve the Chilterns landscape.

Improving the economics of sustainable livestock farming could bring important benefits to biodiversity and sense of place, if associated with targeting graziers to biodiverse grasslands.

Resource-efficient farming should be encouraged and risks identified and managed to reduce negative impacts upon water resources, for example, arable reversion should be targeted to areas of high soil erosion risk and fertiliser use minimised where infiltration into the aquifer is rapid.

Opportunities should be sought to bring relict orchards back into management for food, sense of place and biodiversity benefits.

Principal services offered by opportunities

  • Food provision
  • Sense of place
  • Biodiversity
  • Regulating soil quality
  • Regulating soil erosion
  • Regulating water quality
  • Water availability

Timber provision

Assets/attributes: main contributors to service

  • Beech and conifer woodland
  • Coppice

State – Woodland is found across 14 per cent of the NCA (Natural England, 2010)(or 21 per cent of the Chilterns AONB(Chilterns Area of Outstanding Natural Beauty: Management Plan 2008 – 2013, A Framework for Action, Chilterns Conservation Board)), making this one of the most wooded lowland areas in England and with a potential annual production of 60,000 tonnes (LEADER Local Action Group Local Development Strategy, Chilterns LAG, 2008).

There is approximately 7,000 ha of conifer plantation and 14,000 ha of broadleaved woodland.

1,560 ha of woodland in the public forest estate is managed outside of woodland grant schemes for timber and other ecosystem services.

Main beneficiary – Local

Analysis – During the 18th and 19th centuries, Chiltern woodlands provided a steady supply of beech wood to a significant local furniture industry. Today, timber production is largely limited to conifer woodlands.

The more extensive broadleaved woodlands as well as hedgerow trees, parkland trees and field trees are not commonly managed for timber production. The woodland resource is undermanaged, with problems of over-stood coppice, a lack of thinning and over-mature beech.

Various factors make forestry commercially unviable but particular issues in the Chilterns are the prevalence of beech which has a limited market and costs associated with pests, principally deer and grey squirrel (Ibid). Infrastructure, such as local sawmills, and the local skilled workforce once associated with this area has been in decline.

Opportunities – Opportunities are linked to developing local, small-scale markets and added value products, for example fencing, sustainable and local branded products, (Ibid; Seeing the Wood for the Trees, Forestry Commission, 2004) with associated infrastructure and skills training needs being met. However, wood fuel opportunities may be greater.

Woodlands managed for timber can also be managed to provide public amenity opportunities, conserve heritage and produce biomass.

Principal services offered by opportunities

  • Timber provision
  • Sense of place
  • Sense of history
  • Biodiversity
  • Regulating soil quality
  • Biomass energy

Water availability

Assets/attributes: main contributors to service

  • Beech and conifer woodland
  • Coppice

State – Almost the entire NCA comprises a principal aquifer containing large quantities of high-quality potable water, corresponding with outcropping chalk (Baseline Report Series 6: Chalk of the Colne and Lee River Catchments, Environment Agency and British Geological Survey, 2003). It is the largest principal aquifer in the London Basin and the most significant in southern England. Abstraction volumes and development for abstraction is therefore significant (Catchment Abstraction Management Strategy for Colne, Environment Agency, December 2007).

The majority of volume abstracted in the Chilterns is from groundwater. This contrasts with nearby London or the Upper Thames Clay Vales where surface water abstractions dominate.

In the northern half of the Chilterns, all the rivers and groundwater (There are four Catchment Abstraction Management Strategies (CAMS) applicable to the Chilterns NCA, Upper and Bedford Ouse; Upper Lee; Colne; and Thame and South Chilterns. The CAMS area boundaries and the NCA boundary do not match and so CAMS information is approximated to fit the NCA. Two-thirds of the Chilterns NCA falls into the Colne and Thame and South Chilterns CAMs areas. ) units in the entire Colne catchment and in the Lee and Mimram management unit are ‘over abstracted’.

In the south, all the groundwater units are ‘over licensed’ except the most southern groundwater unit in Oxfordshire which has ‘no water available’. No rivers or groundwater units in the Chilterns are considered suitable for further extraction at low flows.

Water is also imported into the Chilterns. The areas around Wycombe and Aylesbury are net importers from Thames-side sources (Thames Water Utilities Ltd, personal commentary).

Streams become more numerous towards the north. A large area of dip slope in Oxfordshire is without any watercourses and the two southernmost streams can be dry along their entire lengths (Hughenden Stream and Hamble Brook).

A quarter of London’s water supplies is drawn from its underlying confined aquifer which is supported by groundwater flows from the Chilterns and North Downs (State of the Environment Report for London, Greater London Authority, Environment Agency, Natural England and Forestry Commission, June 2011) ).

Groundwater flows in the south of the Chilterns aquifer also supply the nearby River Thames, supporting abstractions downstream including significant volumes for London (Thames Corridor Abstraction Management Strategy, Environment Agency, 2004. The Thames Corridor CAMS covers the freshwater River Thames, from Cricklade to Teddington, and the Thames Tideway as far down as Erith).

Main beneficiary – National

Analysis – South east England is a highly populated area with relatively low annual rainfall. It is also a region with higher than average consumption rates (Thame and South Chiltern Catchment Abstraction Management Strategy, Environment Agency, 2007) and agricultural uses in the Chilterns include ‘high loss’ uses such as spray irrigation (Catchment Abstraction Management Strategy for the Upper Lee, Environment Agency, June 2006). Some parts of the south-east have less useable water per person than some arid countries (Underground, Under Threat – The state of groundwater in England and Wales, Environment Agency, undated).) and more homes are expected to be built.

Public water supply needs, including those of London, have historically caused a greatly depressed water table and low flows in Chiltern chalk streams. Reliance upon groundwater resources will be particularly acute during periods of drought which may also coincide with increased demand by people.

Future demand associated with residential development threatens the sustainability of abstraction26. Water companies, in partnership with the Environment Agency, are carrying out work to address low flows and secure sustainable abstraction, including closing pumping stations and installing pipelines to transfer water.

In the four Environment Agency catchments falling within this NCA, current abstraction at low flows is causing or has the potential to cause, unacceptable environmental damage, with the exception of the dip slope in Oxfordshire and the River Thames reach which are appropriately licensed (Catchment Abstraction Management Strategy for Thame and South Chilterns, Environment Agency, March 2007); Catchment Abstraction Management Strategy for Colne, Environment Agency, December 2007); Catchment Abstraction Management Strategy for the Upper Lee, Environment Agency (June 2006); Catchment Abstraction Management Strategy for Upper and Bedford Ouse, Environment Agency (March 2005); Catchment Abstraction Management Strategy for the Thames Corridor, Environment Agency, June 2004).

The northern catchments which are ‘over abstracted’ in the Chilterns are among only 15 per cent in England and Wales considered to be in this worst state and the availability of water for surface waters are at the highest risk from abstraction (Land Use and Environmental Services, Environment Agency, October 2009; Science Report SC080014/SR1).

This poor picture of water availability is despite the Chilterns annual rainfall being higher than the average for the region. In the southern half of the NCA, the escarpment receives 708 mm average annual rainfall, although only 287 mm reaches watercourses and the aquifer (Catchment Abstraction Management Strategy for Thame and South Chilterns, Environment Agency, March 2007).

Aquifer recharge is greatest high on the escarpment, in the valleys, not on the interfluves, and at the boundary between chalk and clay-with-flint deposits (Baseline Report Series 6: Chalk of the Colne and Lee River Catchments, Environment Agency and British Geological Survey, 2003). Groundwater abstraction is concentrated in the valleys, including the River Thames. Due to hydrological continuity between the watercourses and the aquifer, abstraction from the aquifer draws water from the rivers into the chalk.

Abstraction risks upon the Thames are not considered significant due to its large flows but there are risks to the smaller chalk streams (Groundwater Quality Review – SW Chilterns and Twyford Brook, Environment Agency, February 2005). Infiltration does not take place where there are overlying impermeable deposits, for example clay-with-flint, and where fissures in the chalk are poorly developed across the high ground of Oxfordshire in the south-west (Ibid).

Abstraction pressures contributing to low flows are currently a concern for the rivers Ver, Misbourne, Mimram and Lee. Drying and variable river levels impact upon the ecology of rivers and water-dependent habitats such as meadows and wet woodland. Downstream impacts must also be considered, particularly since Chiltern watercourses contribute water to two key river systems – the River Thames and the rivers feeding into the Ouse Washes and The Wash.

The Thames applies a large draw on groundwater in the south, contributing to a pattern of watercourses across the dip slope that sees an absence of watercourses at the southernmost end in Oxfordshire and increasing density of watercourses northwards.

Opportunities – Opportunities to improve water availability are only effective when implemented on a large scale, with the exception being winter storage reservoirs.

Work in partnership with water companies across the water supply network area to secure sustainable abstraction and consumption, including engaging water consumers about the negative impacts of unsustainable abstraction upon Chiltern chalk streams.

Where recharge potential is greatest across the aquifer, work with land owners and managers to improve soils, vegetation cover and artificial surfaces to enhance infiltration and avoid contamination from, for example, nitrates. Resolve pollution issues at source where there is rapid infiltration.

Support sustainable water consumption and pollution prevention in the design of new developments. Ensure the water supply network can meet demand from new development in a sustainable way.

At a catchment scale, encourage take-up of land management measures that are water efficient and minimise pollution including winter storage reservoirs, best practice irrigation and contour ploughing.

Principal services offered by opportunities

  • Water availability
  • Biodiversity
  • Regulating water quality
  • Regulating water flow

Genetic diversity

Assets/attributes: main contributors to service

  • Orchards

State – Orchards in the central part of the NCA are small remnants of a historically significant local fruit industry.

Main beneficiary – Local

Analysis – Predominantly out of production, these orchards may be in decline, however, they preserve a number of local and unusual varieties.

Opportunities – Engage owners in managing their orchards to conserve the genetic diversity they contain along with their biodiversity and cultural heritage.

Principal services offered by opportunities

  • Genetic diversity
  • Biodiversity
  • Sense of place
  • Sense of history

Biomass energy

Assets/attributes: main contributors to service

  • Woodland
  • Short rotation coppice (SRC)

State – The Energy Crops Scheme 2000- 2006 did not fund any miscanthus or short rotation coppice crops in the Chilterns.

In this heavily wooded landscape, potential yields of biomass from trees are significant from thinnings, logs, chippings and other sources.

Main beneficiary – Local

Analysis – The firewood market is thriving locally, with sale of logs for firewood being more of a driver for woodland management than timber.

The potential yield from miscanthus is limited, while potential for SRC yields are mainly medium. SRC (willow, poplar) is inappropriate in the Chilterns where it reduces infiltration to groundwater, particularly in areas already under water stress.

Suitable locations for biomass production are limited by the presence of vulnerable landscape features and views and also steep terrain, although the heavily wooded landscape offers some opportunities to assimilate SRC. Miscanthus will cause least landscape change if sited where intensive arable already exists, such as on the scarp foothills and Thames Valley.

With approximately 10 million people living within an hour’s drive (including London), there is a large potential market for wood fuel both from the domestic and commercial sector, including large and numerous premises with wood fuel systems, such as Heathrow Terminal 2 and Slough Heat and Power.

Opportunities – Seek growth in the market for woody biomass which secures additional benefits to biodiversity, timber production and conservation of woodland as an important landscape feature (Chilterns AONB State of the Environment Report, Chilterns Conservation Board, 2010).

Establish appropriate management of native beech woodlands which realises their biomass potential and also ensures the conservation of their special biodiversity.

Work with local educational institutions and land owners to develop a skilled workforce to manage woodlands across the NCA.

Principal services offered by opportunities

  • Biomass energy
  • Timber provision
  • Biodiversity
  • Sense of place

Regulating Services

Climate regulation

Assets/attributes: main contributors to service

  • Woodland
  • Permanent pasture
  • Wetland habitats
  • Historic land uses such as downland and parkland

State – Although containing relatively low carbon concentrations, topsoils will contribute to carbon storage capacity.

There are considerable areas of undisturbed soils supporting woodland and permanent pasture, including semi-natural chalk grassland, which are less likely to release their carbon stores and store more carbon than regularly cultivated ground. Permanent grasslands account for approximately 1,500 ha.

Woodland cover is high across the NCA at 14 per cent, representing carbon stores in both soils and tree biomass. Wetland habitats in the valleys which may contain undisturbed peaty and/or deep soils with higher carbon storage capacity account for approximately 400 ha.

Main beneficiary – Regional

Analysis – Soil carbon stores are limited in this NCA due to the predominance of mineral soils. However, carbon storage potential is maximised where there are undisturbed soils which have a considerable longevity of storage such as in historic downland, woodland, common land and parkland.

The contribution that woodland makes to carbon sequestration is very limited compared to the UK’s soil carbon stores and declines with increasing tree maturity. Woodland makes a greater contribution to climate regulation through reducing emissions as a provider of alternative fuels to fossil fuels.

Opportunities – The greatest contribution to be made to climate regulation will be through generating biomass fuels.

Soil carbon stores should be conserved and well managed to maximise storage across the NCA. Incorporate organic matter, use cover crops and adopt reduced tillage techniques to improve soil structure so that there are benefits for carbon regulation, soil quality and soil erosion.

When managing historic landscapes such as downland and parkland, avoid disturbance of soils to benefit long-established carbon stores as well as to preserve above-ground and below-ground archaeology.

Conserve and manage ancient woodlands and their soils to maximise carbon storage while also delivering biodiversity and wood fuel benefits. Forestry activities, including planting and harvesting, should seek to minimise soil disturbance.

Manage existing wetlands and seek to extend wetlands in order to secure the peat resource, benefit biodiversity and manage water resources.

Principal services offered by opportunities

  • Climate regulation
  • Regulating soil quality
  • Biomass energy
  • Sense of history
  • Biodiversity

Regulating coastal erosion and flooding

No information available.

Regulating water quality

Assets/attributes: main contributors to service

  • Chalk Watercourse
  • Vegetated slopes
  • Cross-field hedgerows (in arable)

State – Natural process of water percolating through the Chalk.

Woodland, areas of permanent pasture, cross- field boundary hedgerows and vegetated slopes found throughout the area reduce cross-ground water flow rates thereby increasing infiltration and the processes of natural filtration.

94 per cent of the NCA falls into a nitrate vulnerable zone (NVZ) providing groundwater and surface water protection, and the area around Luton falls into a catchment sensitive farming priority catchment.

Main beneficiary – Regional

Analysis – The NVZ and catchment sensitive farming designations reflect the importance of the area to national water quality interests and to the location of polluting activities. Due to the hydraulic connectivity between groundwater/aquifer and watercourses, pollutants can cross-contaminate.

Groundwater in the aquifer is generally high quality but pollution is present from urban point sources, such as industry in High Wycombe, St Albans, Luton, Dunstable, and from diffuse sources, such as nitrate concentrations from farming; a particular problem in the south of the area.

River water quality is generally good in all but one of the four catchments in the NCA, the Colne, but pollutants are present. Groundwater and surface water protection in this NCA demands filtration of pollutants in both the rural and urban setting, with particular solutions required for the Colne in relation to interactions with the canal network.

Settlement pattern means that urban centres are adjacent to watercourses, where there is limited green space to filter pollutants from runoff. Pollutants in runoff from arable land may be intercepted by the surrounding mosaic of hedgerows, woodlands, scrub and grasslands.

Existence of very rapid flow paths within the Chalk means that groundwater is susceptible to pollution incidents from a wide range of activities and there is potential to cause widespread and long-lasting pollution of the aquifer.

Opportunities – Target the development of sustainable drainage systems / green space within and downstream of urban centres to filter pollutants.

Work with farmers and other land managers at a whole farm and at a catchment scale to maximise and strategically locate land cover which slows and filters run-off and improves water entering the aquifer, for example through arable reversion, hedgerows restoration and planting, permanent arable field margins and strips and reedbeds.

Work with farmers and other land managers to maintain or enhance existing field drainage to improve infiltration and slow down runoff. Avoid new drainage of existing wetlands.

Reduce compaction and erosion in all soils, and poaching in grassland, including remedial loosening.

Encourage sustainable grazing regimes on permanent pasture and rough land.

Principal services offered by opportunities

  • Regulating water quality
  • Food provision
  • Regulating soil erosion
  • Regulation soil quality
  • Regulating water flow
  • Biodiversity

Regulating water flow

Assets/attributes: main contributors to service

  • Watercourses
  • Wooded valley sides
  • Vegetated steep slopes
  • Water storage features, in- stream and in the wider flood plain such as wet meadows and watercress beds
  • Permanent pasture

State – The middle reaches of the River Thames lie near the southern boundary of the NCA, flowing from the adjacent NCA Upper Thames Tributaries and on to London. The Thames flows across a wide flood plain offering flood storage capacity.

The Thames Valley has a fairly high risk of flooding, with riverside settlements including Reading, Henley and Marlow susceptible. The Thames Valley also offers potential floodwater storage areas.

Smaller scale flooding may also affect those settlements adjacent to chalk streams in the dip slope valleys but, historically low flows have been a more significant issue.

Some watercourses are prone to drying in their upper reaches and the permeability of the Chalk means that infiltration can reduce overland flows. Five of the nine chalk streams are classified as ‘heavily modified waterbodies’.

There are landscape features which assist infiltration and slow overland flows, including extensive broadleaved woodland and a locally dense network of hedgerows.

Main beneficiary – Local

Analysis – Groundwater provides a relatively consistent flow volume to chalk streams. However, abstraction can give rise to artificial and low flow regimes which impact the ecology of rivers and water- dependent habitats such as meadows and wet woodland.

Abstraction pressures contributing to low flows are currently a concern for the rivers Ver, Misbourne, Mimram and Lee. Treated discharges from sewage treatment works modify flows of rivers such as the Lee and Hiz.

Low flow alleviation schemes have been implemented along several chalk streams including the Misbourne, Bulbourne and Wye (Thames Water Utilities Ltd, personal commentary). Pumping stations along chalk streams have been closed and investigations continue along rivers such as the Wye. Chalk streams within the Chilterns AONB also benefit from the conservation activities of the Chiltern Chalk Streams Project which has been running for several years.

Downstream impacts must also be considered, particularly since Chiltern watercourses contribute water to two key river systems – the River Thames and the rivers feeding into the Ouse Washes and The Wash.

Across the Chalk, infiltration can reduce overland flows after rainfall events and so alleviate localised flooding. However, flooding can affect the many urban centres adjacent to chalk streams where there is significant run-off and limited flood storage space (with associated water pollution threats). The Thames can bring floodwaters into the NCA and on into London.

Narrow valleys on the dip slope restrict flood storage capacity while the wide Thames flood plain offers some opportunity for storage. The dominance of heavily modified watercourses amongst the chalk streams means natural river processes are restricted at times of high water flows.

Establish land cover which slows runoff in the urban and rural environments. The role that water flow management in the Upper Thames Tributaries can play in attenuating Thames floodwater will also benefit this NCA and London.

Opportunities – Target the development of sustainable drainage systems and green space within and downstream of urban centres to store floodwaters and filter pollutants.

Work with farmers and other land managers at a whole catchment scale to improve soil management to aid water infiltration and to maximise and strategically locate land cover which slows and filters run-off, for example through arable reversion, hedgerows restoration and planting, permanent arable field margins, wooded slopes and reedbeds.

Restore historic and natural features in flood plains to increase capacity for water storage, including wet meadows, watercress beds and reedbed.

Principal services offered by opportunities

  • Regulating water flow
  • Regulating water quality
  • Water availability
  • Biodiversity

Regulating soil quality

Assets/attributes: main contributors to service

  • Permanent pasture
  • Calcareous soils
  • Grade 1, 2 and 3a land
  • Soils under woodland

State – Prime agricultural land of Grades 1 and 2 is associated with the lower scarp and Thames flood plain and covers about 10 per cent of the NCA area or about 18,000 ha.

There are soil types of a calcareous nature which are naturally resilient to drought if well managed. These are shallow lime-rich soils over chalk or limestone covering around 15 per cent of the NCA and also freely draining lime- rich loamy soils which account for just over 10 per cent of the NCA area.

Soils across approximately half the NCA are vulnerable to compaction. These include the slightly acid loamy and clayey soils associated with the dip slope ridges (covering just over 40 per cent) and the freely draining slightly acid but base-rich soils (covering just over 10 per cent).

There are considerable areas of uncultivated soils under woodland and grassland, some of which have been undisturbed for centuries such as ancient woodland, downland and fen. Permanent grasslands account for approximately 1,500 ha and fen 52 ha. Woodland cover is high at around 23,000 ha, of which 12,000 ha is ancient.

Main beneficiary – Regional

Analysis – The best and most versatile agricultural land (Grade 1, 2 and 3a) is a priority for protection from loss by development. Almost half the NCA, including much of the plateau, is vulnerable to poaching and compaction and this threatens soil structure, versatility and productivity.

The national importance of the chalk aquifer makes overlying soil structure and soil contaminants significant in terms of water filtration.

There are significant potential pollutant sources including urban centres, roads and intensive agriculture.

Opportunities – Conserve and maximise the resource, aiming particularly to avoid deterioration of soils with high Agricultural Land Classification grades. Ensure there is good soil management in woodlands as well as across farmland.

Across all soils, reduce soil compaction and erosion. Avoid land management practices which can lead to compaction such as over-stocking and working machinery on wet ground.

Carry out remedial work such as loosening where necessary.

Reducing intensity of tillage and encouraging use of additional sources of organic matter on intensively managed soils, such as cover/catch crops and manures, should help increase soil carbon and improve soil structure. This, with careful use of fertilisers, should help reduce nitrous oxide emissions.

Good soil management will also benefit food production in the long term, aid infiltration to the aquifer and reduce pollutants entering surface and ground waters.

Principal services offered by opportunities

  • Regulating soil quality
  • Regulating soil erosion
  • Food provision
  • Regulating water quality
  • Regulating water flow
  • Water availability
  • Climate regulation
  • Biodiversity

Regulating soil erosion

Assets/attributes: main contributors to service

  • Soils
  • Permanent pasture
  • Woodland

State – Steep slopes across the Chilterns make soils vulnerable to erosion under certain land uses. Some Chiltern soils types are also intrinsically vulnerable to erosion.

The extensive woodland cover protects a large proportion of Chiltern soils.

Soils under permanent vegetation – grassland and scrub – are less prone to wind or water erosion.

Main beneficiary – Local

Analysis – Soil management is critical as many of the Chiltern soil types are vulnerable to damage and hence erosion. Erosion of thin chalk soils can lead to total loss of soil to expose bare rock. Soils under woodland will be conserved but are not accessible for food production.

With the NCA falling into a Nitrate Vulnerable Zone overlying a regionally/nationally important aquifer, soil erosion is a concern in relation to water quality because water can transfer sediments and contaminants into groundwater and surface water.

The predominant loamy and clayey soils with impeded drainage, covering almost half the NCA, are easily compacted by machinery or livestock if accessed when wet, increasing the risks of soil erosion by surface water run-off. The majority of these soils are also prone to capping/slaking, as are some of the freely draining lightly acid but base-rich soils (around 10 per cent of the NCA), leading to increased risk of erosion.

The shallower lime-rich soils (around 15 per cent of the NCA) are at risk of erosion on sloping cultivated ground or where bare soil is exposed, as are the freely draining lightly acid loamy soils (covering about 20 per cent of the NCA), where there is also the potential for wind erosion on some coarse textured cultivated variants. The remaining loamy/ clayey soils (flood plain or seasonally wet soil types covering less than 5 per cent of the NCA) are at low risk of erosion.

Opportunities – Encourage farmers and land managers to manage land on steep slopes as pasture, especially where there are thin chalk soils and where biodiversity benefits are significant.

Incorporate organic matter, adopt reduced tillage and avoid compaction in order to minimise runoff and soil erosion.

Incorporate features such as hedgerows and grassland buffers which can intercept runoff and so reduce widespread erosion, filter contaminants and enhance the landscape.

Encourage longer growing periods between grazing and increase sward diversity in leys to increase root penetration and increased soil stability.

Principal services offered by opportunities

  • Regulating soil erosion
  • Regulating soil quality
  • Regulating water quality
  • Food provision

Pollination

Assets/attributes: main contributors to service

  • Species-rich grassland
  • Hedgerows
  • Woodland edge

State – Habitats supporting pollinating insects are provided by the Chilterns’ hedgerows, species-rich grasslands, wetlands and exposed rock.

Main beneficiary – Local

Analysis – In the Chilterns AONB, a 2008 survey found wheat growing on 50 per cent of cropped land; 20 per cent barley and 11 per cent oilseed rape (Chilterns AONB Land Use Survey 2008, Chilterns Conservation Board, 2008). Graminae species, such as maize and cereals, dominate Chilterns’ crops and are wind pollinated so do not require pollinators. However, crops that are insect pollinated and are grown here now and may be in the future include soft and top fruit, linseed, oil seed rape, and a variety of beans.

Opportunities – Maintain pollinator habitat and, where possible, create new pollinator habitat.

Where crops are grown that require insect pollination, create new pollinator habitats including chalk grassland.

Principal services offered by opportunities

  • Pollination
  • Food provision
  • Biodiversity

Pest regulation

Assets/attributes: main contributors to service

  • Habitat mosaic

State – The high degree of heterogeneity in the landscape, as opposed to a monoculture landscape, provides resilience against widespread pest and disease damage.

Main beneficiary – Local

Analysis – There is recognised pest damage affecting timber production/trees in the Chilterns: mammals including grey squirrels, fat dormouse), muntjac and fallow deer, and insects, including oak processionary moth at Pangbourne and west London, and horse chestnut leaf miner. Sudden oak death, ash dieback and red band needle blight are also affecting trees in the Chilterns (Chilterns AONB State of the Environment Report, Chilterns Conservation Board, 2010).

Non-native species such as signal crayfish are also threatening native aquatic biodiversity. The mosaic of woodlands, hedgerows and watercourses may facilitate disease and pest dispersal. However, the mosaic of habitats will potentially support natural predators.

Opportunities: Maintain and build resilience against pests and diseases by supporting diversity within species populations and in terms of habitats and crop types. Focus upon managing impacts upon food and timber provision and biodiversity.

Establish pest and disease management strategies for the Chilterns woodlands and watercourses in particular.

Principal services offered by opportunities

  • Pest regulation
  • Timber production
  • Biodiversity

Cultural Services

Sense of place/inspiration

Assets/attributes: main contributors to service

  • Panoramic views
  • Beechwoods
  • Historic environment
  • Watercourses
  • Escarpment
  • River Thames
  • Traditional built environment
  • Downland
  • Open access land and rights of way
  • Farms hosting school visits

State – As a result of the special qualities of much of this landscape 52 per cent is designated AONB – the majority being the Chilterns AONB and a small area to the south of the Thames being the North Wessex Downs AONB.

There is public access to locations and viewpoints with diverse and ancient natural and cultural heritage, including barrows and hill forts, and rare and unique features, such as the Chiltern gentian and Whiteleaf Cross, a carved chalk figure. Wide views and feelings of space and height are also gained from high points overlooking the clay vales or valley flood plains.

A dense hedgerow network, holloways, woodland and branching steep valleys create an intimate landscape in places.

The Thames is a dominant feature in the south.

Consistent use of traditional building materials provides consistency and connection with local geology. Attractive villages and dispersed farmsteads give a sense of rural tranquillity and affluence while large urban centres and major roads are busy.

Designed landscapes provide a sense of grandeur.

Local museums celebrate local, personalities, artistic endeavour and heritage, for example the Roald Dahl Museum and Henley River and Rowing Museum.

Nineteen farms in the NCA host school visits under agri-environment schemes (Based on analysis of agri-environment scheme data held by Natural England, 2012).

Main beneficiary – National

Analysis – Some modern development is reinforcing traditional building styles, particularly in the AONB. The AONB designation of the majority of this NCA reflects a strong scenic and landscape character and provides resources for conserving and enhancing the natural beauty of the area. Natural and cultural heritage is accessible and celebrated in local museums, parklands, urban spaces, countryside sites and on commons.

Local communities are active in engaging both local people and visitors in local heritage through town centre trails, museums, promoted countryside routes and events. Several farms host school visits to engage children in their local working countryside, but there are few near to London.

There is an absence of strong local brands associated with food, wood or other products, suggesting that the identity of the working landscape is not as strong as it could be. In the past, orchard produce was associated strongly with this area; a characteristic now widely lost. The Chilterns AONB considers that the conservation of the built environment is largely dependent upon outside sources for materials and skills (Chilterns Area of Outstanding Natural Beauty: Management Plan 2008 – 2013 – A Framework for Action, Chilterns Conservation Board, undated). The area continues to provide stimulation for many writers, artists, poets and painters.

Opportunities – Work with the AONB to conserve and enhance the landscape and the special qualities of the AONB and consider applications of best practice beyond the AONB boundary.

Further develop strong locality products where this supports the management of the landscape, for example woodland and sheep farming products and local building materials.

Further engage active communities in conserving and enhancing the landscape, and the distinctive physical and cultural character of the area.

Engage farms near to London in hosting school visits.

Principal services offered by opportunities

  • Sense of place/ inspiration
  • Sense of history
  • Food provision
  • Biodiversity
  • Geodiversity

Sense of history

Assets/attributes: main contributors to service

  • Scheduled Monuments and other, unscheduled heritage assets
  • Registered Parks and Gardens
  • Listed buildings
  • Traditional built environment, both urban and rural
  • Ancient natural features Ancient woodlands and their traditional management and production

State – There are 202 Scheduled Monuments, including parts of the well known prehistoric routeway called the Ridgeway.

Around 15 of these monuments are declining in condition and on the At Risk Register. Additional monuments are at risk and of an unknown or stable condition.

Bronze-age barrows and iron-age hill forts and dykes found along the scarp connected by the Icknield Way which has been in use since the Neolithic period.

Iron-age hillforts and dykes found along the Thames Valley to the south.

Roman influence is still evident through the communications network and settlement pattern, and medieval influence is reflected in settlement and field patterns.

Chalk streams reveal unique features associated with watercress growing and numerous mill sites.

Main beneficiary – Regional

Analysis – The history of the landscape is evident in numerous historic features from various ages dating back to prehistory.
Some historic features are widespread, including ancient boundaries, holloways, commons, ancient woodlands, churches, and buildings in the vernacular style.

Public access is provided to some key heritage assets and landscapes including parklands, monuments along the Ridgeway and commons, increasing the opportunity to understand and interpret the historic environment.

Woodland archaeology reveals changes in woodland management and climate including coppice stools linked to medieval activities and saw pits and other features associated with the furniture industry of the 18th and 19th centuries.

Opportunities – Engage communities and owners of historic features in celebrating and conserving the historic environment, including developing skills and industry around historic environment conservation and traditional building materials and construction.

Improve public access and visitor facilities to key historic features.

Enhance the setting of historic features as part of landscape- scale projects which integrate multiple landscape objectives.

Establish positive management of woodlands which conserves their archaeology and draws on traditional techniques while also benefitting biodiversity, wood fuel production and carbon storage.

Principal services offered by opportunities

  • Sense of history
  • Sense of place/ inspiration
  • Timber provision
  • Biodiversity
  • Geodiversity
  • Recreation

Tranquility

Assets/attributes: main contributors to service

  • Secluded valleys
  • Scarp
  • Woodland

State – The largest area of high to medium tranquillity is in the south-west, including around Henley-on-Thames.

Elsewhere, parts of the escarpment and a few valleys without major roads and settlements are highly tranquil and there are also very small pockets of medium to high tranquillity near to the London edge, for example between Amersham and Hemel Hempstead.

Only 20 per cent of the NCA is assessed as ‘undisturbed’.

Main beneficiary – Regional

Analysis – The Chilterns is a transitional area in which levels and areas of tranquillity increase with distance away from London, except in the north where Luton and Stevenage influence tranquillity.

Low tranquillity scores are dispersed across the NCA reflecting settlements and major transport corridors.

Experiences of tranquillity in those pockets of high to medium tranquillity near to the London edge and in the Thames Valley will be particularly significant and valued.

Luton and Stevenage are a focus for further development and so the surrounding areas of high to medium tranquil spaces may be detrimentally affected.

Traffic, a key contributor to disturbance, affects popular countryside visitor destinations as well as more traditional rural settlements. Traffic calming measures and support for non-car transport has reduced traffic issues at Ashridge.

Opportunities

Distinctive elements of the Chilterns landscape, woodlands, flowing water and the ‘rural’ scene, should be conserved and managed to improve perceptions of tranquillity, particularly near to settlements.

Traffic calming measures and support for non-car travel at popular countryside destinations should be encouraged and supported and will improve tranquillity and recreation experiences generally.

Further erosion of tranquillity should be avoided or minimised by ensuring development in areas of high to medium tranquillity is appropriate to the setting and incorporates measures, such as tree planting and green ‘buffers’.

Principal services offered by opportunities

  • Sense of tranquility
  • Sense of place/ inspiration
  • Sense of history
  • Recreation

Recreation

Assets/attributes: main contributors to service

  • Ridgeway National Trail
  • Thames Path National Trail
  • Open access land
  • Public rights of way
  • National cycle routes and regional trails
  • Grand Union Canal Public forest estate
  • Historic parks and gardens
  • River Thames The scarp slope

State – More publicly accessible routes and green spaces are needed for the populations of Luton, Hemel Hempstead and High Wycombe but other settlements have good access provision per head of population (Based on visual analysis of countryside access data held by Natural England, 2012).

There are 3,563 km (equivalent to 2.17 km per km2) of rights of way, and over 3,500 ha of open access land (around 2.5 per cent of the NCA), including significant tracts of common land.

There are three National Nature Reserves. 1,560 ha of woodland in the public forest estate is managed outside woodland grant schemes for timber and other ecosystem services.

Two National Trails run through the area; the Ridgeway follows the crest of the scarp and the Thames Path follows the course of the river. There are a number of National Cycle Network routes and regional routes, the Icknield Way and the Chiltern Way. The Ridgeway, Grand Union Canal and National Cycle routes are multi-user routes along much of their length.

Water-based activities are provided along the Thames and Grand Union Canal.

There are a wide range of activities offered by this area, for example walking, cycling, horse riding, gliding, canoeing, mountain biking, canal boating and bird watching (Chilterns Area of Outstanding Natural Beauty: Management Plan 2008 – 2013 – A Framework for Action, Chilterns Conservation Board, undated). A large number of organisations provide events for the public (Ibid). The Chiltern Society volunteer groups assist in the maintenance of the rights of way network.

Visitor experiences at some sites may be negatively impacted by congestion and noise.

Main beneficiary – Regional

Analysis – In 2007, it was estimated that there were just over 55 million leisure visits made to the Chilterns AONB (Chilterns AONB Visitor Survey 2007, Tourism South East, 2008). A survey at 11 sites in the AONB established that 74 per cent of visits were made by local residents and 83 per cent were made by groups; family and/or friends (Ibid).

The Chilterns represents an important local recreational resource for approximately 1.38 million residents in the 11 district council areas in which the AONB falls. In addition, the area is easily accessible from London and other major urban centres, such as Milton Keynes, and offers relative tranquillity (Chilterns Area of Outstanding Natural Beauty: Management Plan 2008 – 2013 – A Framework for Action, Chilterns Conservation Board, undated).

Some locations are recognised ‘honey pot’ sites, for example, Wendover Woods and Ashridge Estate (Chilterns AONB Visitor Survey 2007, Tourism South East, 2008) and the resilience of these sites’ features to visitor pressure is a concern. Traffic on rural routes also affects enjoyment.

A survey of 11 sites in the Chilterns AONB also suggested the majority of visits involve passive activities, such as walking or enjoying the view, rather than active pursuits such as off-roading or paragliding (Ibid).

There is demand for more multi- user routes, particularly along the Thames Path.

Common land, lying in close proximity to homes, workplaces and schools, is particularly well used. Large areas are open to the public by the National Trust, Forestry Commission, wildlife trusts and local authorities, with a particular assemblage along the ridge providing some of the best views in the area (Chilterns Area of Outstanding Natural Beauty: Management Plan 2008 – 2013 – A Framework for Action, Chilterns Conservation Board, undated).

The percentage of open access land and accessible natural green space (Accessible natural green spaces are areas of countryside that provide both public access and a potential wildlife habitat – woodlands, grasslands, wetlands, rivers, canals and country parks) in the AONB is relatively high and well spread. Locally promoted routes equally serve different users, including ‘easy access’ circular trails.

Approximately three-quarters of accessible natural green space is woodland, with around a third of open access woodlands being provided by the Forestry Commission. Key landscape features are accessible and offer a broad appeal, including picturesque villages, waterways, biodiverse habitats and historic places (Chilterns Area of Outstanding Natural Beauty: Management Plan 2008 – 2013 – A Framework for Action, Chilterns Conservation Board, undated).

Boat traffic has reduced along the Thames in recent years (Ibid).

Opportunities

Improve the bridleway network as a multi-user network and also to meet the demands of the considerable resident population of horse owners.

Manage visitor pressure upon fragile locations by promoting alternative, more robust and equally attractive destinations and increase the resilience of vulnerable sites.

Maximise the contribution that volunteers and local communities can make to the maintenance of landscape features which are recreational assets.

Support, create and improve links between recreational assets and settlements.

Address gaps in the provision of routes and green spaces, targeting efforts around Luton, Hemel Hempstead and High Wycombe.

Principal services offered by opportunities

  • Recreation
  • Biodiversity
  • Sense of place/ inspiration
  • Sense of history

Biodiversity

Assets/attributes: main contributors to service

  • Species- rich chalk grassland
  • Ancient woodland Ancient hedgerows
  • Sustainably managed farmland
  • Chalk streams
  • Common land habitats
  • Parkland Farmland birds Arable weeds
  • Local Nature Reserves

State – Recognised at an international level, the beechwood SACs cover just less than 1 per cent of the NCA.

There are 3,670 ha of land designated SSSI, dominated by chalk grassland and broadleaved woodland. 98 per cent of SSSI are in ‘favourable’ or ‘unfavourable recovering’ condition.

There are 1,062 Local Wildlife Sites. The provision of Local Nature Reserves does not meet the recommended 1 ha per 1000 population in any district.

Biodiversity of parklands, chalk streams and orchards is under-represented amongst all designated sites.

Semi-natural habitats are restricted in extent, except woodland. Chalk grassland and common land habitats exist as scattered fragments, although the extensive hedgerow network provides potential linkages.

Chalk streams support characteristic species and also strengthening populations of water vole. However, the ecological status of the rivers Gade and Ver is considered ‘bad’ and less than five waterbodies are considered ‘good’.

Arable weeds are localised but there are strong populations of shepherd’s needle, for example. Farmland birds include corn bunting, grey partridge and yellowhammer.

The red kite draws visitors to the Chilterns, as do rare plants such as the pasque flower at Barton Hills NNR.

Main beneficiary – National

Analysis – Important areas and types of semi- natural habitat are designated, although stretches of chalk stream, ancient hedgerow, parkland and farmland biodiversity are under- represented.

Larger areas of woodland, common and grassland represent core areas of habitat. Chalk streams and ancient hedgerows can function as corridors.

Declining livestock numbers have made conservation of open habitats difficult, giving rise to significant losses to scrub and woodland. Open habitats are largely conserved only where agri-environment schemes support management.

Conservation of woodland biodiversity relies upon grant schemes, although a growing wood fuel market is reviving management in some woods. Many woods have long been unmanaged, leading to declines in woodland birds and butterflies. Orchards are largely unmanaged.

Farmland birds benefit from the mosaic of habitats and from sustainable farming practices supported by agri-environment schemes.

Chalk stream ecology is negatively affected by low flows, engineered channels and pollution. Low flow alleviation schemes, resource protection measures across farmland and improvements delivered by community groups are improving condition in some places.

Chalk streams within the Chilterns AONB have benefitted from a dedicated long-running Chalk Streams Project which promotes best practice conservation and development and supports conservation activities. Project work has secured improvements to stream and flood plain habitats along several rivers including restoration of water meadows and improved fish passage along the Chess (Annual Report 2011-12, Chilterns Chalk Streams Project, undated).

Commons and riversides are significant as biodiverse spaces near to settlements. Access to urban-edge grasslands and woodlands may also be significant for local people to experience ‘common’ or ‘urban’ wildlife.

Local Nature Reserves are relatively few considering the population size. With many key areas of habitat, including downland, being subject to public access, there can be issues around visitor pressure and conflict between visitors and management activities.

Local authorities, private farms, the National Trust, Wildlife Trusts and Forestry Commission provide public access to biodiverse sites. Promoted routes and interpretation boards in the countryside celebrate the natural interest of the Chilterns.

Landowners deliver nature conservation management under agri-environment schemes while numerous community groups and organisations also carry out nature conservation work.

Opportunities – Establish a resilient ecological network. Identify and address gaps and build core areas, particularly in relation to chalk grassland and flood plain habitats. Incorporate access improvements to provide for public engagement with nature

Realise greater recognition of the biodiversity interest of parkland, chalk streams and orchards by seeking designations as appropriate and by integrating biodiversity conservation into management of associated historic assets.

Conserve important species populations in semi natural and farmland settings through supporting sustainable farming. Where possible, management to conserve biodiversity should also seek to assist water and soil conservation, focusing upon areas where risks are highest and the value of the asset greatest, for example, chalk grassland on steep slopes or wet meadows alongside a chalk stream.

Engage local communities and landowners in conserving their local biodiverse spaces as part of a wider, co-ordinated ecological network, particularly those near settlements and popular with visitors such as Barton Hills NNR.

Restore chalk streams, flood plain habitats and flood plain function. Innovative solutions will be required along significant stretches of watercourse due to the constraints of existing development and settlement.

Review the Local Nature Reserve resource and identify and address any gaps, particularly where new development is taking place.

Secure biodiverse green infrastructure as part of development.

Manage visitor pressure upon fragile locations by promoting alternative, more robust and attractive destinations and increasing the resilience of vulnerable sites.

Principal services offered by opportunities

  • Recreation
  • Biodiversity
  • Sense of place/ inspiration
  • Sense of history

Geodiversity

Assets/attributes: main contributors to service

  • Chalk
  • River terrace gravels
  • Fluvial geomorphology

State – There are 14 geological SSSI and 33 Local Geological Sites. The form of the Chilterns Chalk outcrop is prominent and a distinctive landform that is visible and accessible for interpretation.

Some periglacial landforms, such as dry valleys, chalk carved figures and disused quarries, some of which are designated, are accessible by the public, for example. Whiteleaf Cross, College Lake, Totternhoe Quarry. Landforms of the Thames Valley, including the Goring Gap and gravel pits, can be accessed and enjoyed by the public from the Thames Path and from locally popular vantage points such as Winter Hill, near Cookham.

Traditional building materials also celebrate local geology. Local museums and promoted routes contribute to the interpretation of local geodiversity. There are local community groups carrying out geoconservation and public engagement activities.

Pitstone Quarry SSSI is famous for an organic deposit (around 180,000 years BP) which is evidence of a previously unknown British interglacial.

Main beneficiary – National

Analysis – The geology and processes that underpin the area have generated much of the areas agriculture, land use and now cultural heritage. Despite being almost entirely underlain by the Chalk, a diversity of soils have developed through the interplay of climate, topography, vegetation and human influence, which in turn support the characteristic habitats and land uses across the Chilterns.

Of the few green spaces with very good visitor facilities such as car parks and visitor centres, many have geodiversity interest that can be promoted to the public.

Historic buildings built with local materials and historic excavation sites on commons also represent an important resource near to settlement. Public access to exposures of chalk is rare and new excavations are not taking place.

Those groups which are seeking to engage the public and study geodiversity have restricted resources, relying largely on volunteers, consequently public engagement in geodiversity is small-scale.

Opportunities – Work with existing and new groups, including landowners of green spaces, to build capacity to carry out geoconservation activities and education.

Secure benefits to geodiversity through landscape scale projects which integrate multiple landscape objectives.

Engage communities and property owners in celebrating and continuing use of local building materials, including developing skills and industry around traditional building materials.

The relationship between geodiversity in this area and the underlying aquifer, water quality and availability, and soils presents an opportunity to engage a wide audience in better understanding natural processes that limit available resources.

Principal services offered by opportunities

  • Geodiversity
  • Sense of place/ inspiration
  • Sense of history
  • Recreation