National Character Area 81

Greater Thames Estuary - Natural Capital and Key Ecosystem Services

Introduction

The Greater Thames Estuary 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 Greater Thames Estuary 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.

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 NCA contains extensive areas of land (49 per cent per cent) under agricultural management with cultivation of cereal crops dominating extensive areas of ploughed, drained former marshland to produce wheat and barley. Traditional wet pasture is grazed with sheep and cattle and more mixed agriculture occurs on higher ground. Estuarine waters support an important commercial fishing industry including shellfish.

Water availability: Large areas of the Kent coastline have surface water available for abstraction, including the Isle of Sheppey and the northern reaches of the Medway. Water is more limited on the Essex side of the Estuary with no water available during low flows, but water available in some systems during median and high flows. Within London, some water is abstracted from the principal London Basin Chalk aquifer. Water is mainly used for commercial purposes but also for industry and farming. 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: Significant carbon storage is provided by extensive areas of salt marsh, reedbeds, mudflats and grazing marsh.

Regulating soil quality: The dominant loamy and clayey soils of the coastal flood plain provide fertile arable land when adequately drained, although they are increasingly under threat from loss due to sea level rise. Compaction of seasonally wet soils may reduce water infiltration and increase surface water run-off.

Regulating water quality: Chemical status is mixed with the north of the NCA classed as good, and the Greater London and Kent areas as failing, and this is reflected in the status of coastal and estuarine waters. The ecological quality of the area’s rivers is generally moderate, although some towards London are poor and the ecological potential of the estuary waters again reflects this assessment, apart from the mouth of the Colne Estuary and Hamford Water which have achieved good status. The quality of water in the NCA is highly dependent on waters upstream.

Pollination: The NCA is important for some of the UK’s rarest bumblebees and three priority species are strongly associated with its dry, flower-rich habitat: the shrill carder bee, brown-banded carder bee and moss carder bee. Coastal habitats (including grazing marsh) and open mosaic habitat on brownfield sites provide important nectar sources and nesting opportunities for pollinators.

Regulating coastal flooding and erosion: The major risk of flooding in the area comes from the sea, with large areas of reclaimed arable land and grazing marsh below sea level and maintained by sea defences. Flood defence structures occur all along the estuary coastline. The extensive coastal habitats, especially salt marsh, provide an important natural defence against flooding by reducing the impact of wave action on the coastline and its defences. Coastal habitats are, however, being lost at a rapid rate due to coastal squeeze. Shoreline Management Plans assess coastal processes and the management of the coastline. Areas of the estuary have also been identified as potential sites to store tidal waters during very large surge tides to help prevent increased flooding of the River Thames. There is the opportunity to create compensatory coastal habitat arising from losses identified in plans such as TE2100 (the Environment Agency’s strategic plan for managing flood risk in the Thames Estuary). 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: A sense of place is provided by the flat, open and expansive estuarine landscape where distinctive shallow creeks, drowned estuaries, low islands, mudflats and broad tracts of tidal salt marsh and reclaimed grazing marsh provide a strong sense of remoteness and skyscapes dominate the views. Historic settlement and field patterns and coastal military landmarks add a human aspect, and a large and varied bird population adds movement to the landscape. The close proximity of the highly urbanised and industrial areas of East London provides a marked contrast to the remoteness of the coastal marshland.

Sense of history: The distinctive military associations along the coastline, including the naval dockyards, provide the most evident sense of the historical importance of the area in protecting London from invasion by the sea. Other important archaeological features include ancient sea walls, iron-age/Roman salt mounds, bronze-age funerary monuments and the Saxon minster churches. London itself provides a rich source of history.

Tranquillity: High levels of tranquillity remain in the parts of the NCA which are not in proximity to London. Tranquil areas are generally associated with the expansive and remote mudflats and coastal marshes.

Recreation: Recreational opportunities are provided by the Thames Path National Trail, Saxon Shore Way and 1,136 km of public footpaths. This will be enhanced by the current development of the Thames Estuary Path. Recreation is also provided by popular beach resorts, fossil-hunting sites and various water-based recreational activities including fishing and boating. The internationally important coastal habitats also attract many visitors for their birdwatching opportunities.

Biodiversity: The estuary is of international importance for its coastal habitats and over 15,000 ha are covered by international designations including one Special Area of Conservation, ten Special Protection Areas and ten Ramsar sites. The estuary contains significant areas of salt marsh (the largest remaining area in England), intertidal sand and mudflats, sand dunes, shingle, shell and sand banks, subtidal sand and mud, and extensive areas of coastal grazing marsh. The salt marsh and grazing marsh habitats are internationally important for their diverse assemblages of wetland plants and invertebrates, such as pedunculate sea-purslane.

The estuary supports hundreds of thousands of wintering waterfowl and breeding wetland birds, notably dark-bellied Brent geese. Intertidal and subtidal coastal habitats support a variety of marine wildlife. Arable land within the NCA provides important bird foraging and breeding habitat and its field margins support invertebrate species. Brownfield sites contain a rich mosaic of habitats supporting nationally important invertebrates, some found only in this area of England.

Geodiversity: The NCA contains geological sites of significant importance both nationally and internationally. The Tertiary sediments of sands and clays that comprise the eastern edge of the London Basin contain fossils of both national and international importance. The NCA also contains important stratigraphic evidence of a major glacial event 450,000 years ago which was responsible for the shift in the course of the River Thames, and sites that preserve evidence of past climates, landscapes and biodiversity along with evidence of early humans and the landscape they lived in around 400,000 years ago. The NCA coastline is of major geomorphological interest for its system of estuaries characterised by a maze of winding, shallow tidal creeks that dissect islands, mudflats, sandflats and salt marsh where natural active coastal processes can be observed.