134 - Dorset Downs and Cranborne Chase : Natural Capital and Key Ecosystem Services

Introduction

The Dorset Downs and Cranborne Chase 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 Dorset Downs and Cranborne Chase 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:
 

• 10: Dorset
• 17: Hampshire and the Isle of Wight
• 43: Wiltshire

Provisioning services (food, fibre and water supply)

Food provision: The NCA is an important arable area, growing significant amounts of cereals and, increasingly, oil seeds (although it is possible that up to 70 per cent of these are grown as biofuel precursors). Dairy farming has declined but is still All livestock numbers have fallen, but cattle, sheep and pigs are still present in significant numbers.

Timber provision: The 2,000 ha of coniferous plantation is a profitable timber-producing sector in the NCA, and the timber is sold into national The 8,836 ha of broadleaved and 1046 ha of mixed woodland are underutilised in terms of timber.

Water availability: The chalk that underlies the whole NCA forms a very important set of These supply drinking water to several large towns and parts of the Bournemouth-Poole conurbation. The rivers flowing out of the NCA are also heavily dependent on groundwater from springs to maintain and regulate their flows. For information regarding the current state of water availability within this NCA, refer to the Environment Agency (Abstraction Licensing Strategy).

Regulating services (water purification, air quality maintenance and climate regulation)

Regulating soil erosion: Many of the lighter soils that make for such good arable production are also susceptible to erosion, from both wind and run-off. Compaction and poaching can exacerbate the problem.

Regulating soil quality: Soil quality is essential to maintaining the successful arable operations in the NCA, along with the recharging of the groundwater aquifers.

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).

Cultural services (inspiration, education and wellbeing)

Sense of place/inspiration: The history of Cranborne Chase as a hunting forest has given it a strong sense of The works of Thomas Hardy have, more than the real history of this NCA, defined its place in the popular imagination.

Sense of history: A multitude of heritage assets and cultural associations, and a ‘time depth’ extending into the prehistoric period, all give this NCA a strong sense of

Tranquility: Very low densities of development and few major roads mean that many parts of this NCA have a high level of Expansion of the two major towns and increased traffic on the trunk roads has, however, eroded this to some extent.

Biodiversity: Internationally important concentrations of chalk grassland are found within the NCA, along with a distinctive suite of associated species. This habitat is much reduced and fragmented, and in need of landscape-scale Tracts of semi-natural ancient woodland (some extensive) provide a second habitat of importance. Again, much reduced and fragmented, it is significantly out of management and in need of interventions to reclaim aspects of its biodiversity interest. The NCA also features a suite of chalk streams that support a range of rare plants and animals, again recognised internationally.

Geodiversity: The NCA is dominated by its Chalk geology and Quaternary landscapes. Disused quarries and pits are particularly important in understanding the late Jurassic, Cretaceous and Tertiary history – not only of this NCA, but also of the south of England and all of For example, quarries (designated as an SSSI) at Upwey and Bincombe Down expose rare late Jurassic and early Cretaceous sediments, while the West Harnham Chalk Pit SSSI is important for our understanding of both Chalk geology and the later uplift caused by Alpine mountain-building. The landscape of dry valleys and combes, features such as the swallow hole at Cull-Peppers Dish SSSI, and the development of sarsens all add to our understanding of the evolution of the Quaternary landscape across southern England.