REVIEW: Towards a risk register for natural capital

Summary Natural capital is essential for goods and services on which people depend. Yet pressures on the environment mean that natural capital assets are continuing to decline and degrade, putting such benefits at risk. Systematic monitoring of natural assets is a major challenge that could be both unaffordable and unmanageable without a way to focus efforts. Here we introduce a simple approach, based on the commonly used management tool of a risk register, to highlight natural assets whose condition places benefits at risk. We undertake a preliminary assessment using a risk register for natural capital assets in the UK based solely on existing information. The status and trends of natural capital assets are assessed using asset–benefit relationships for ten kinds of benefits (food, fibre (timber), energy, aesthetics, freshwater (quality), recreation, clean air, wildlife, hazard protection and equable climate) across eight broad habitat types in the UK based on three dimensions of natural capital within each of the habitat types (quality, quantity and spatial configuration). We estimate the status and trends of benefits relative to societal targets using existing regulatory limits and policy commitments, and allocate scores of high, medium or low risk to asset–benefit relationships that are both subject to management and of concern. The risk register approach reveals substantial gaps in knowledge about asset–benefit relationships which limit the scope and rigour of the assessment (especially for marine and urban habitats). Nevertheless, we find strong indications that certain assets (in freshwater, mountain, moors and heathland habitats) are at high risk in relation to their ability to sustain certain benefits (especially freshwater, wildlife and climate regulation). Synthesis and applications. With directed data gathering, especially to monitor trends, improve metrics related to asset–benefit relationships, and improve understanding of nonlinearities and thresholds, the natural capital risk register could provide a useful tool. If updated regularly, it could direct monitoring efforts, focus research and protect and manage those natural assets where benefits are at highest risk.


W Hazard protection
Quality It is not the quality of the A/U that determines the benefit, but quantity and spatial configuration of woodland, and therefore uptake of water and binding of soils.

Spatial configuration
No relationship -storage of carbon can occur anywhere.

FW Food Spatial configuration
No relationship -it does not matter where fish production occurs assuming infrastructure is in place to transport to beneficiaries.

FW Fibre Spatial configuration
No relationship -it does not matter where reeds are grown, assuming infrastructure is in place to transport reeds to beneficiaries. Currently a large proportion of UK's reed product needs are met by imports.

FW Energy Quantity
No relationship -it is not considered realistic to increase the extent of the A/U unit e.g. rivers to provide more hydro power due to complexity of conditions that determine where these habitats occur.

MMH Food
Quantity MMH is of low/medium low importance in providing food. MMH naturally have low agricultural productivity due to soil properties, water logging and topography (sheep predominant use) therefore classed as poor quality agricultural land. Although we could influence the quantity and quality characteristics, this would be limited to the margins (e.g. change in lowland heath) and there would be negligible change in total benefit produced from the A/U over the next 25 yrs.

MMH
Fibre Quantity MMH is of low/medium low importance in providing fibre, sheep wool by product of sheep meat-little market value. Although we could influence the quantity and quality characteristics, there would be negligible change in total benefit produced from the A/U over the next 25 yrs.

MMH Clean water Quantity
The relationship is considered to be +L (none/negligible).
The quantity of the A/U could decrease through change in land use (e.g. to woodland, to enclosed farmland) or development, however the potential to increase the extent of the habitats is limited to the margins e.g. heath areas, majority of other subcomponents require specific topographic conditions to exist. As any changes in extent will be minimal, the impact to benefit produced over the next 25yrs will be none/negligible. Although MMH significant source of water (70% UK drinking water) -coincidental in location -quantity of the A/U does not significantly affect amount of water.

MMH Recreation Quantity
The relationship is considered to be +L (none/negligible).
The quantity of the A/U could decrease through change in land use (e.g. to woodland, to enclosed farmland) or development, however the potential to increase the extent of the habitats is limited to the margins e.g. heath areas, majority of other subcomponents require specific conditions to exist. As any changes in extent will be minimal, the impact to benefit produced over the next 25yrs will be none/negligible.

Quality
The relationship is considered to be +NL (none/negligible).
The use of MMH for recreation e.g. mountain biking, walking etc will largely be determined by access, and material capital investments e.g. trails, footpaths etc, and the maintenance of these. The impact to the benefit produced over 25yrs, resulting from a change in quality, is considered to be none/negligible. Recreation = f [land (topography, altitude); material capital (management practices -trails, footpaths, access to rock faces for climbing)] -

MMH Aesthetics Quantity
The relationship is considered to be +L (none/negligible).
It is considered that most of the aesthetic value of MMH is the scenery and sense of wilderness, and what is available will be highly valued.
The quantity of the A/U could decrease through change in land use (e.g. to woodland, to enclosed farmland) or development, however the potential to increase the extent of the habitats is limited to the margins e.g. heath areas, majority of other subcomponents require specific conditions to exist and therefore unlikely to be adversely affected by land use changes. As any changes in extent will be minimal, the impact to benefit produced over 25yrs will be none/negligible.

EF Food Spatial configuration
The relationship is considered to be +NL (none/negligible).
Although we can influence the spatial configuration of enclosed farmland, this does not influence the total benefit produced or its value i.e. it does not matter where produce food. It is also acknowledged that some geology/soils are more fertile than others, however again, society cannot influence where these occur, can just utilise for best output.
-EF Fibre Quantity Enclosed farmland is of low/medium low importance in providing fibre (considered to be a secondary crop to food production). Although we could influence the quantity, quality and spatial configuration characteristics, there would be negligible change in total value of benefit produced because of low ES provision from the A/U over the next 25 yrs. -

Quality -
Spatial configuration -EF Energy Spatial configuration The relationship is considered to be +NL (none/negligible).
Although we can influence the spatial configuration of EF, this does not influence the value of the benefit produced i.e. it does not matter where produce biofuel. It is also acknowledged that some geology/soils are more fertile than others, however again, society cannot influence where these occur, can just utilise for best output. -

EF Clean water Spatial configuration
The relationship is considered to be +NL (none/negligible).
Although we can influence the spatial configuration of EF, this is not considered to significantly change the amount of the benefit produced -other over-riding factors would affect location of farms. -

EF Clean air Quantity
The relationship is considered to be -NL (none/negligible).
Although we can influence the quantity of EF, and therefore potential for air quality issues (vehicle emissions), this is not considered to significantly change the amount of the benefit produced. (urban A/U greater contributor). -

EF Recreation Quantity
The relationship is considered to be +NL (none/negligible).
Although we can change the quantity of EF, this is not considered to significantly change the benefit producedthis is primarily determined by the quality characteristic .i.e. access. -

EF Aesthetics Quality
The relationship is considered to be +NL (none/negligible).
Although we can influence the quality of EF to improve aesthetics e.g. greater heterogeneity of farming types in the landscape is likely to be more aesthetically pleasing than a homogenous farming landscape, this is not considered to significantly change the amount of the benefit produced.

Spatial configuration
The relationship is considered to be +NL (none/negligible).
Although we can influence the spatial configuration of EF to bring closer to people, this is not considered to significantly change the amount of the benefit produced and overriding factor of locality. -

Quantity
The relationship is considered to be -NL (none/negligible).
Although we can influence the quantity of EF, this is not considered to significantly change the amount of the benefit producedquality more important. However it is assumed that there is a level of soil erosion under baseline quality conditions, and therefore an increase in area of EF would have some impact flooding (increased sediment in rivers potentially causing flooding problem)

Quantity
The relationship is considered to be -NL (none/negligible).
Although the area of enclosed farmland can be increased, the stocking density of livestock that give rise to methane emissions is part of the quality characteristic at baseline it is assumed some increase.

SNG Food
Quantity SNG is of low/medium low importance in providing food. Although we could influence the quantity, quality and spatial configuration characteristics for food, there would be negligible change in benefit produced from the A/U over the next 25 yrs. Livestock grazing on improved grasslands has been included in the Enclosed Farmland A/U.

Spatial configuration
-SNG Fibre Quantity Semi-natural grasslands is of low/medium low importance in providing fibre. Although we could influence the quantity, quality and spatial configuration characteristics, there would be negligible change in benefit produced from the A/U over the next 25 yrs. -

Spatial configuration
-

Recreation Quantity
The relationship is considered to be +NL (none/negligible).
It is assumed that all SNG could be replaced with another A/U. The first units of grassland will be highly valued, however, at a critical amount i.e. enough grassland to satisfy recreational demands, any increases over this will not be as valued. The overall increase in area of semi-natural grassland is considered to be limited, as it is dependent on underlying geological conditions.
As only 1%, potential change in quantity is limited and also ability to extend (due to underling geological conditions required).

Quality
The relationship is considered to be +NL (none/negligible).
The recreational benefits from SNG will be governed by low level management e.g. light grazing, management of footpaths. Overall it is considered that there is limited requirement to improve the quality of the A/U for recreational benefits assuming access in place.

SNG Aesthetic Quantity
The relationship is considered to be +NL (none/negligible).
It is assumed that all SNG could be replaced with another A/U. The first units of grassland will be highly valued, however, at a critical amount i.e. enough grassland to satisfy recreational demands, any increases over this will not be as valued. The overall increase in area of semi-natural grassland is considered to be limited, as it is dependent on underlying geological conditions.
As only 1%, potential change in quantity is limited and also ability to extend (due to underling geological conditions required). -

Quantity
The relationship is considered to be +NL (none/negligible).
It is assumed that all semi-natural grassland could be replaced with another A/U therefore the value crosses the origin. The first units of grassland will be highly valued, however, at a critical amount i.e. enough grassland to satisfy recreational demands, any increases over this will not be as valued. The overall increase in area of seminatural grassland is considered to be limited, as it is dependent on underlying geological conditions.
-W Food Quantity Woodland A/U is of low importance in providing food. Although we could influence the quantity, quality and spatial configuration characteristics, there would be negligible change in total benefit produced from the A/U over The relationship is considered to be +NL (none/negligible).
It is the quantity that drives the change in benefit more than the quality i.e. amount of timber grown for biofuel.
However, aspects of quality of the A/U can affect the yield. In a poor quality environment e.g. high levels of acidification, low nutrient cycling, tree growth will be poor and therefore limit yield.
It may also be possible to select the species that are grown, to select those with quickest growth rates. Improvements in material capital to harvest the timber will also increase the amount of output.

W Clean air Quality
The relationship is considered to be +NL (none/negligible) It is the quantity that drive the change in benefit i.e. more woodland equals greater potential to absorb pollutants and increase O 2 production. Spatial configuration The relationship is considered to be +NL (none/negligible).
UK NEA suggests that trees could be planted around livestock units to reduce pollution spreading, and it is considered that the same approach could be applied to roads to absorb pollutants. However, the overall change in benefit is considered to be minimal, with the greatest change driven by quantity of trees (0 2 production, pollutant absorption). Please note, the importance of greenspace and trees is considered in the urban A/U.

FW Food Quantity
The relationship is considered to be +L (none/negligible).
The overall value of food from freshwater (fish) is considered to be low when compared to EF (crops and -livestock).
As the number of waterbodies increases, the potential for use for aquaculture also increases. However, the overall change in extent is considered to be small i.e. cannot significantly increase number of rivers or lakes. FW Fibre Quantity The relationship is considered to be +L (none/negligible).
Although the UK NEA identifies that there is a strong demand for quality thatching reed, this is considered to be relatively low in value compared to other fibre products e.g. timber from woodland.
It is also considered that the area of reedbed available for harvesting is unlikely to increase considerably if the area of 'freshwater' increases due to prevailing conditions limiting how much habitat can be created. -

Quality (Wetland)
The relationship is considered to be +NL (none/negligible).
The quality of the wetland subcomponent will affect reed growth and therefore amount that can be harvested and sold. However the future provision is considered to be low.
In a degraded wetland, it is considered unlikely that there would be sufficient quantity of reeds to be commercially viable to harvest. However, as the quality of the wetland increases, the quantity and quality of reeds available for harvesting will increase significantly. At a critical point, further improvements will not significantly increase value from reed yield.

FW Clean water Spatial configuration
The relationship is considered to be +NL (none/negligible).
Storage reservoirs and water treatment works are typically located within close proximity to populations, or where rainfall or river flows are high. However, there is an historic context to this as water supply components will be developed where cities have developed i.e. close to populations. Distribution networks connect a range of water supply components which may be some miles from the beneficiary.
The location of wetlands can alter the effectiveness of purification, with some being located in areas of between sources of pollutants and the main watercourse. However, this is considered to have a negligible effect to the overall cost of treating water for use. -

Recreation Quantity
The relationship is considered to be +L (none/negligible).
It is assumed that freshwater is valued moderately high for aesthetics e.g. coastal margins and MMH more valued.
Although you can change the area of some of the subcomponents e.g. wetlands, reservoirs, you cannot significantly change the area of the A/U for a recreational benefit. Wetlands and reservoirs are normally created for another purpose (e.g. wildlife, clean water) and recreation is a by-product. -

FW Aesthetics Quantity
The relationship is considered to be +L (none/negligible).
It is assumed that freshwater is valued moderately high for aesthetics e.g. coastal margins and MMH more valued.
It is considered that you cannot significantly change the area of the A/U, just around the margins such as the wetland subcomponent. These changes in area will not give rise to a significant change in value.

Spatial configuration
The relationship is considered to be +NL (none/negligible).
The proximity of freshwater to populations will be valued, although there will be a certain distance which is acceptable, and any improvements on this will not be valued as greatly and ability to change limited. -

Quantity
The relationship is considered to be -NL (none/negligible).
As the number of waterbodies increases, the potential for flooding also increases. With a low extent of waterbodies, the avoided cost of flood protection is high, as waterbodies increases, and therefore risk of flooding increases, this avoided cost decreases. However, it is considered that you cannot significantly change the area of the A/U, just around the margins such as the wetland subcomponent. These changes in area will not give rise to a significant change in benefit.

U Food Quantity
The urban A/U is of low/medium low importance in providing food. Although we could influence the quantity and quality characteristics, there would be negligible change in total value of benefit produced from the A/U over the next 25 yrs.

U Clean water Spatial configuration
The relationship is considered to be +NL (none/negligible).
Urban greenspaces could be arranged to act as interceptors to pollution before it enters watercourses. However, the change in value to the clean water benefit is considered to be negligible with the greatest impact arising through replacement techniques e.g. SUDS, material capital investments such as Thames Tideway Tunnel (these not considered as part of the current scope of work to inform the risk register) -U

Clean air Spatial configuration
The relationship is considered to be +NL (none/negligible).
It is considered that urban greenspaces could be configured to maximise potential to scavenge pollutants however the change of value to the clean air benefit is considered to be negligible given the overall impact of the built urban environment on air quality.

Quality
The relationship is considered to be +NL (none/negligible) The quality of the built urban environment could be improved by reducing the area of impermeable surfaces, and maximising potential of greenspaces to reduce surface water runoff.

Spatial configuration
The relationship is considered to be +L (none/negligible).
It is considered that urban greenspaces could be configured to maximise potential to intercept rainfall and reduce surface water runoff however the change of value to the protection from hazards benefit is considered to be negligible given the overall impact of the built urban environment and reliance on replacement techniques to reduce the impact. -

CM Food Quantity
Saltmarsh and sand dunes The relationship is considered to be +NL (none/negligible) Older established saltmarsh and sand dune grasslands are used for grazing livestock (predominantly sheep) (UK NEA 2011). The current provision of food from this A/U is considered to be low when compared to EF and M. Although there is potential to reduce the quantity of these subcomponents through land use change, the ability to increase them is limited as they are the ultimate stage of succession for these habitats. Quality

Saltmarsh and sand dunes
The relationship is considered to be +NL (none/negligible) The saltmarsh and sand dunes which support livestock typically have a soil profile to support grass. Anything that affects the store of soil will affect the amount of benefit that can be produced. However, this is considered to be minimal as the grassland successional stage is well established and least vulnerable to erosion. CM Fibre Quantity The relationships are considered to be +NL (none/negligible) Coastal margins are of low importance in providing fibre (wool). Although we could influence the quantity and quality characteristics (spatial configuration cannot be changed), there would be negligible change in total benefit produced from the A/U over the next 25 yrs.

CM Clean water Quality
The relationship is considered to be +NL (none/negligible).
It is assumed that as the quality of the habitat increases, its ability to purify also increases. It is considered that a limited number of aquifers benefit from this process, with the majority of aquifers in England being inland, and -therefore the overall value of an increase in quality is minimal. As stated in the UK NEA, Dungeness is the only shingle site which provides a local source of drinking water. The benefit in purification is to the marine A/U.
The ability to increase the quantity is limited e.g. some subcomponents only such as saltmarsh. Minor changes in the quantity of these habitats are not considered to be significantly valued for recreation. -

CM Aesthetic Quantity
The relationship is considered to be +L (none/negligible).
The ability to increase the quantity is limited e.g. some subcomponents only such as saltmarsh. Changes in the quantity of these habitats are not considered to be significantly valued for aesthetics. -

M Aesthetic Quality
The relationship is considered to be +NL (none/negligible).
The quality of the marine environment, and wider sea views, can be affected by offshore windfarms (perceived as both positive and negative impacts on landscape). The change in value of the benefit is considered to be none/negligible.

Quality
The relationship is considered to be +NL (none/negligible).
Marine organisms regulate the climate by acting as a sink for carbon dioxide and facilitating burial of carbon in seabed sediment. This is done by photosynthesis and also storage of carbon in shells (calcium carbonate).
The abundance and diversity of marine flora and fauna will be primarily determined by the quality of the water. This will increase up to a critical point, after which any increase in quality, and therefore associated species abundance, will be less valued. However, our ability to change or influence the benefit by human management is considered to be limited.

MMH Energy Quantity
Blanket bog and heath (habitats on peatland) The relationship is considered to be +L (minor/moderate).
Peat is a non-renewable energy source; only the rate of extraction/consumption can be managed.
The quantity of the A/U could decrease through change in land use (e.g. heaths and bogs to grassland) or development, however the potential to increase the extent of the habitats is limited e.g. blanket bog requires certain conditions to exist. Therefore any changes in extent will be small.
The timescales over which appropriate conditions need to be present to allow the formation of peat are considerable (decades). Peat has a slow rate of natural regeneration (mms per year), and therefore management would aim to maintain the 'stock' of peat that could be extracted for fuel, as this could be degraded. However, the change in quantity is often driven by a change in quality e.g. soil erosion (see below). Quality The relationship is considered to be +NL (minor/moderate).
Peat will only form under certain conditions. If you graze or burn blanket bog, the species required for peat formation e.g. sphagnum moss etc, will be lost by the resultant lowering of the water table and drying of the existing peat layer. The vegetation will be replaced by heath species typical of drier conditions.
Suitable land management is therefore crucial in determining whether the stock of peat will be retained by ensuring continued conditions for it formation.
The current provision of peat for energy is low and localised (UK NEA 2011, pg 126), and the UK Government is implementing measures to reduce peat use.

MMH Wildlife Spatial configuration
The relationship is considered to be +NL (minor/moderate).
The connectivity of habitats, e.g. blanket bogs and heaths, is important for maintaining wildlife. However, the ability to fragment with other land uses and/or provide better connectivity is considered to be limited by underlying conditions required for formation (e.g. geology, altitude, high precipitation etc.)

MMH
Equable climate Quantity Blanket bog The relationship is considered to be +L (minor/moderate).
The quantity of the A/U could decrease through change in land use (e.g. heaths and bogs to grassland) or development, however the potential to increase the extent of the habitats is limited e.g. blanket bog requires certain conditions to exist. Therefore any changes in extent will be small. However, given the importance of blanket bog in carbon sequestration, the impact in benefit produced over 25yrs is considered to be minor/moderate.

EF Energy Quantity
The relationship is considered to be +NL (minor/moderate).
There is potential to both increase and decrease the area of the A/U, and the proportion of the A/U which is devoted to production of biofuels rather than food. As the quantity of the A/U increases so does the potential to produce biofuel and therefore resultant value. However, this will be limited by the market demand and therefore there will be a critical area required, after which increases in area will no longer be as highly valued.
Given the current provision of benefit from A/U, considered to be minor/moderate.

Quality
The relationship is considered to be +NL (minor/moderate).
The amount of biofuel that can be produced from EF will depend upon the quality of the habitat, but more importantly the material capital investment made to produce the crop.
Poor quality habitats will not produce large amounts of biofuel and therefore the value will be low. As this increases, the value will significantly increase up to an optimal point, where after further improvements in quality will no longer give such substantial increases in benefit value.

EF Recreation Quality
The relationship is considered to be +NL (minor/moderate).
The quality of enclosed farmland can significantly affect the value of recreation e.g. through use of set aside to create game shooting areas, improve access arrangements.

EF Aesthetic Quantity
The relationship is considered to be +NL (minor/moderate).
There is potential to both increase and decrease the area of the A/U, which could result in a loss of the farming heritage from the wider landscape. The future provision to aesthetics is considered to be minor/moderate.

SNG Wildlife Spatial configuration
The relationship is considered to be +NL (minor/moderate) Semi-natural grassland is geographically constrained by underlying geology, but land use changes could interrupt the overall connectivity. However as SNG occupies only 1% of England land, and a large proportion is protected to some degree (68% of SNG is within SSSI, other designations also protect e.g. SAC, AONB), the ability to influence connectivity is considered to be limited, although could be significant in terms wildlife abundance and diversity.

W Energy Quantity
The relationship is considered to be +NL (minor/moderate).
The quantity of the A/U can be changed, with the potential for all areas of woodland to be converted to a different land use. Therefore the first unit of woodland will be highly valued. However, there will be a point where the area of woodland satisfies market demand, and any increase in quantity thereafter will not be as valued.
Overall, the value of woodland for biofuel will be lower than the value for timber, as biofuel is readily substitutable and therefore there is a lower demand.

W Recreation Quality
The relationship is +NL (minor/moderate).
The quality of recreation will largely be governed by the management practices i.e. improving access, felling, coppicing, and creating recreational opportunities e.g. mountain biking trails, zip lines etc. The species composition of the woodland is not likely to be as important for recreational activities.
As management improves the recreational facilities, the value will increase. At a certain point, further improvements will no longer be as valued.
Although different species may have different capacities and uptake rates of CO 2 it is predominantly the quantity of woodland that will give the greatest benefit. However the age of the woodland will also be important in CO 2 uptake in younger woodlands greater than mature woodlands. Species composition may also affect rates of uptake.

FW Food Quality
The relationship is considered to be +NL (minor/moderate).
Overall value of food from freshwater (fish), and the contribution quality has to this, will be low. It is considered that the majority of fish production is undertaken in artificially created habitats, with high levels of human management, although noted that high value fish such as salmon can only be reared in high quality water courses.
In a degraded/poor environment (either for water abstraction for artificial habitats or the natural system), the quantity and quality of water will limit fish production, with improvement in quality, fish production will increase. At a critical point, further improvements will not significantly increase value from fish production.
The value of benefit realised is dependent on the positioning of material capital to harness the energy i.e. create dams in upland areas where there is sufficient flow, vertical distance (head) and volume of water, with low suspended sediment.

Recreation Spatial configuration
The relationship is considered to be +NL (minor/moderate).
The proximity of freshwater to populations will be valued, although there will be a certain distance which is acceptable, and any improvements on this will not be valued as greatly. It also considered that there is a limit on the number of waterbodies that could be created near to populations to increase value from spatial configuration.

U Clean water
Quality Built urban The relationship is considered to be +NL (minor/moderate).
The impact from the built urban subcomponent on clean water is generally derived from combined sewer overflows during storm events and polluted surface water runoff that gets into the watercourses. Changes to use of cars, littering, reduced loading etc could reduce this. The main improvements would require the use of SUDS, oil interceptors etc and material capital investments e.g. Thames Tideway Tunnel are required. However these are all replacement techniques to reduce the impact of the urban A/U and not considered as part of the scope for the risk register work.

Greenspace
The relationship is considered to be +NL (minor/moderate).
Poor quality greenspace is considered to be that which is unmanaged e.g. overgrown towpath, or possibly lacking in facilities e.g. greenspace with no play area in close proximity to residential housing i.e. active enjoyment of the greenspace is difficult. Pristine quality greenspace is that which is well managed and offers the facilities desired by the public.
The initial unit of greenspace within the urban will be valued, but as the quality improves, this will increase. However, after a certain level of improvements, any additions are no longer as highly valued i.e. the marginal increase is less. The relationship is considered to be +NL (minor/moderate).
The built urban subcomponent of the A/U is considered to have a negative effect on flooding due to the extent of impermeable surfaces. A poor environment would be one of high impermeability, whereas a well designed environment would incorporate urban green spaces to intercept rainfall and reduce surface water runoff.

Spatial configuration
The relationship is considered to be +NL (minor/moderate) It is considered that urban greenspaces could be configured to maximise potential to intercept rainfall and reduce surface water runoff however the change of value to the protection from hazards benefit is considered to be negligible given the overall impact of the built urban environment and reliance on replacement techniques to reduce the impact.

M Recreation Quality
The relationship is considered to be +NL (minor/moderate).
The value of recreation can be improved with artificial reefs (e.g. surfing) and decreased through no-catch zones (angling).

Prioritised Relationships
Major relationships A/U Benefit Characteristic Relationship Justification Graph

MMH Clean water
Quality Blanket bog The relationship is +NL (major).
As the quality of blanket bog improves, the cost of treating water to drinking water standards will decrease -peat accumulation immobilises nutrients i.e. when not degraded, organic carbon, N etc held in place which would otherwise be released into water. The impact of degraded peatland on clean water is considered to be significant.

MMH Aesthetics Quality
The relationship is considered to be +NL (major).
The quality of MMH can affect the 'sense of experience' gained from the A/U. Although the value of MMH for aesthetics will largely be determined by the land form which cannot be influenced by society. Appropriate management of the habitats e.g. heath could be considered to enhance views, with degraded habitats not offering the same 'scenery' as good or pristine habitats. (Note, the aesthetic appeal of special plant and animal life is considered under the 'wildlife' benefit).

Spatial configuration
The relationship is considered to be +NL (major).
Although the spatial configuration of the A/U cannot be influenced by society as it is defined by altitude (over 300m), the extent of it, and therefore aesthetic appeal, can be interrupted if the landscape is fragmented by urban area, tall structures or other land uses i.e. anything that interrupts the view, sense of wilderness. A continuous landscape is considered to be highly valued for aesthetics and therefore any impact on this are considered to be significant.

MMH Hazard protection Quantity
The relationship is considered to be -NL (minor/moderate) for heaths and fire risk. The relationship between blanket bog and flooding is also considered to be -NL but there is a high level of uncertainty on significance.
There is the possibility of decreasing and to some extent increasing the quantity (although small) of some of the MMH subcomponents (blanket bogs and heaths) through land use changes e.g. afforestation, expansion of enclosed farmland.
Wildfire is a risk, with heath being particularly susceptible and therefore if the quantity increased, the potential risk of fire would also increase.
There is uncertainty around the role of blanket bog and flooding. As detailed in UK NEA 2011, historically have considered blanket bog as acting as a sponge and holding water, however good quality blanket bog would have a high water table, and therefore little capacity to hold additional water during a storm event. This could give rise to surface water runoff which would lead to increased flooding downstream.
There is also some uncertainty over the role of quantity in soil erosion and slope instability. Assuming the current baseline quality (eroding blanket bog) it would be assumed that an increase in quantity would have a negative effect on soil stability.
Given the uncertainty of the relationships, this has been upgraded to major and will therefore be taken forward for further consideration in the risk register.

Quality
The relationship is considered to be +NL (minor/moderate) for both fire and soil stability.
Wildfire risk can be decreased by managed burns to reduce the biomass present (UK NEA), with older heath having a higher fuel load (certain). Degraded blanket bog is also likely to increase the risk of fire, as the drier habitat will potentially assist in the spread of fire whilst a better quality habitat, which is wetter, is likely to reduce the spread (uncertain).
It is unclear how blanket bog affects flooding (as stated above, the high water table could lead to runoff), however it is considered that a degraded blanket bog with grips and gullies would allow more efficient runoff of surface water during a storm event and therefore potentially increase flooding downstream (uncertain).
A degraded blanket bog will experience soil erosion which could lead to slope instability (uncertain).
Wildlife risk = f [ecological communities (heath biomass, blanket bog); soils (eroding); freshwater (low water Given the uncertainty of the relationships, this has been upgraded to major and will therefore be taken forward for further consideration in the risk register.

MMH Wildlife Quantity
The relationship is considered to be +L (major).
There is the possibility of decreasing and to some extent increasing the quantity (although small) of some of the MMH subcomponents (blanket bogs and heaths) through land use changes e.g. afforestation, expansion of enclosed farmland.
The quantity will be important in determining the size of a population that can be supported i.e. carrying capacity. As the area increases, although only at the margins, there is potential to increase the abundance of species (note that quality is probably more important in determining the variety of species).

Quality
The relationship is considered to be +NL (major).
'Pristine' MMHs are those which have a high level of heterogeneity, supporting a mosaic of habitats. These in turn support a range of highly specialised species.
It is considered that people will highly value habitats

Benefit Characteristic Relationship Justification Graph
nearing 'pristine' condition and although the contribution of additional species may only be of marginal value after this, the value will still increase.
It is considered that land management practices can be both beneficial for wildlife, or adversely affect the wildlife. For example, a transition from heather to grass has been observed following an increase in pressure from sheepgrazing with consequences for plant diversity. Sheep preferentially graze grasses but utilise heather and other dwarf shrubs along the edge of grass patches and paths (Palmer et al. 2003). Consequently, the condition of heather can be severely impacted by grazers and ultimately leads to grass-dominance across hill slopes (UK NEA, pg 116). However, low intensity grazing could also be beneficial in reducing scrub succession. The relationship is considered to be +NL (major).
Blanket bog will only form under certain conditions. If you graze or burn blanket bog, the species required for peat formation, and those which store carbon, i.e. sphagnum moss, will be lost by the resultant lowering of the water table and drying of the existing peat layer. The vegetation

Benefit Characteristic Relationship Justification Graph
will be replaced by heath species typical of drier conditions.
Suitable land management is therefore crucial in determining whether peat will continue to form and sequester carbon, or whether the locked carbon could be released through poor management.
Peat formation = f [species (sphagnum moss); ecological communities (photosynthesis and carbon locking); soils (high acidity, organic matter and water holding capacity, nutrient availability); atmosphere (temperatures, rainfall, CO 2 , N); freshwater (high water The quantity of the A/U can be increased, and as this does, so does the potential to produce food. However, this will be limited by the market demand and therefore there will A/U

Benefit Characteristic Relationship Justification Graph
be critical area required, after which increases in area will no longer be as highly valued.

Quality
The relationship is considered to be +NL (major).
The amount of food that can be produced from enclosed farmland will depend upon the quality of the habitat, but more importantly the material capital investment made to produce food. Poor quality habitats will not produce large amounts of food and therefore the value will be low. As this increases, the value will significantly increase up to an optimal point, where after further improvements in quality will no longer give such substantial increases in benefit value.
Most improved grassland is managed to provide food for livestock, mainly sheep and beef and dairy cattle. It is typically in the form of 'improved' pasture or long-term leys, managed using herbicides, fertilisers, ploughing, reseeding, liming and drainage to favour competitive, nitrogen-responsive grasses which provide silage to feed livestock over the winter and grazing for the rest of the Under baseline quality conditions, as the area of enclosed farmland increases the detrimental effect to water quality will also increase and this is considered to be significant.

Quality
The relationship is considered to be +NL (major).
The quality of EF can significantly affect clean water through improvements in water quality e.g. through use of buffer strips to capture pollutants before they enter watercourses, reduced application of fertilisers will reduce nutrient enrichment of watercourses.
Water quality = f [species; ecological communities (pollination, pollutant uptake); soils (exposure); freshwater (temperature, suspended sediment); land (aspect, altitude, gradient, exposure to wind); atmosphere (temperature, rainfall, wind); material capital (management practices e.g. use of buffer strips, reduced application of fertilisers, ploughing direction to reduce soil erosion, crop rotation to maximise uptake of nutrients for different plant species)]

Quality
The relationship is considered to be +NL (major).
The quality of the habitat is considered to affect the potential for flooding downstream, with degraded habitats being affected by soil erosion which can be transported to the river networks by surface water runoff.
Agriculture contributes to approximately 75% of sediment getting into watercourses (Reducing and controlling agricultural pollution, Defra website). A third of waterbodies are at risk from eroded soil (Environment Agency, Corporate Strategy 2010-2015).

EF Wildlife Quantity
The relationship is considered to be +NL (major).
EF habitats cover 60% of England (SoNE, 2008). Under baseline quality conditions, as the area of enclosed farmland increases the detrimental effect to wildlife will also increase and are likely to be significant.

Quality
The relationship is considered to be +NL (major).
The quality of the habitat can significantly affect the wildlife value e.g. using buffer strips, set aside lands, increase number of waterbodies on land, reduce use of pesticides, reduce monoculture farming.
There has been a catastrophic decline in the distribution of arable flowering plants during the last half century and they are now amongst the most threatened elements of our flora (Smith 1989 Wildlife = f [species; ecological communities (pollination); soils; land; atmosphere; material capital (management practices e.g. use of buffer strips, set aside schemes, creation of waterbodies, reduction in pesticide application, reduction in monoculture)]

Spatial configuration
The relationship is considered to be +NL (major).
EF and hedgerow connectivity is important in allowing wildlife to move not only around the EF A/U but between other A/Us that are separated by EF e.g. woodland, seminatural grassland.

Quality
The relationship is considered to be +NL (major).
UK agriculture generates net greenhouse gas emissions, with emissions from agriculture accounting for around 7.0% of the UK total (although variation between countries) -nitrous oxide (53% of total agriculture emissions in 2008) and methane (38% of total agriculture To improve equable climate, a greater proportion of crops should be grown compared to livestock, thereby taking in CO 2 and reducing methane emissions. However, the realisation of this change in quality would be driven by a change in consumer demand which would constrain change.
To reduce NOx emissions, changes should be made to the amount of fertiliser applied and timing, manure left on soils, etc which affect emissions. Grassland soils are important carbon stores and the level of tillage can affect the amount of carbon released.
The emissions can be driven by the number of livestock animals, the characteristics of those animals (i.e. their breed, size, yield, digestive systems, etc.), what livestock are fed (for example, a diet with a higher maize content can maintain animal performance while decreasing the production of methane), and how manures are managed (CCC 2010).
There is potential to reduce greenhouse gas emissions from arable systems through improved soil, fertiliser and agrochemical management (Smith et al. 2008;Macleod et al. 2010). Nitrous oxide emissions arising from crops and soils can be decreased by good nutrient planning, including improving efficiency in using fertiliser by, for example, taking full account of nitrogen in manure applications, timing applications to match crop requirements, using

Benefit Characteristic Relationship Justification Graph
composts and straw-based manures in preference to slurry where practical, and separating slurry and mineral nitrogen application (UK NEA, pg 216).
The quality of SNG can affect the 'sense of experience' gained from the A/U. Although the value of SNG for aesthetics will largely be determined by the land form which cannot be influenced by society, appropriate management of the habitats e.g. removal of scrub could be considered as enhancing views, with degraded habitats not offering the same 'scenery' as good or pristine habitats. (Note, the aesthetic appeal of special plant and animal life is considered under the 'wildlife' benefit) The initial unit of semi-natural grasslands will be valued, and as the quality improves, this will increase. However, after a certain level of improvements to the habitat, any additions are no longer as valued i.e. the marginal increase is less. Aesthetics = f [land (topography, altitude); material capital (management practices -grazing, scrub clearance)]

Spatial configuration
The relationship is considered to be +NL (major).
Although the spatial configuration of the A/U cannot be easily changed by human management as it is generally defined by geology, the extent of it, and therefore aesthetic appeal, can be interrupted if the landscape is fragmented by urban area, tall structures or other land uses i.e. anything that interrupts the view. A continuous landscape is considered to be highly valued for aesthetics.

SNG Wildlife Quantity
The relationship is considered to be +NL (major).
It is assumed that all SNG could be replaced with another A/U however the potential to increase the extent of the A/U is considered to be limited as it is dependent on underlying geological conditions. Therefore any changes in extent will be small.
The quantity will be important in determining the size of a population that can be supported i.e. carrying capacity. As the area increases, although only at the margins, there is potential to increase the abundance of species (note that quality is probably more important in determining the variety of species).

Quality
The relationship is considered to be +NL (major) Lowland grassland priority habitats (dry acid and calcareous grasslands, lowland meadows, purple moorgrass and rush pastures) are home to 206 UK BAP species, while upland grassland priority habitats (calcareous grasslands and upland hay meadows) are home to 41 (UK NEA).
The main adverse factors affecting SSSI condition are undergrazing, poorly timed grazing and lack of scrub control. These factors allow increased dominance of rank grasses and scrub at the expense of more desirable but less competitive species (SoNE Report, 2008) Poor management of the habitats could lead to a release of this stored carbon e.g. soil erosion. However, it is unclear how quickly carbon would be released -carbon stock is in the upper 15cm of soil.
Carbon storage = f [ecological communities; soils; land (topography, exposure) atmosphere (temperature, rainfall, CO 2 , SO 2 ); pressures (grazing, cutting, scrub management)] Given the uncertainty of the relationship, this has been upgraded to major and will therefore be taken forward for further consideration in the risk register. W Fibre Quantity The relationship is considered to be +NL (major).
The quantity of the A/U can be changed, with the potential for all areas of woodland to be converted to a different land use. Therefore the first unit of woodland will be highly A/U Benefit Characteristic Relationship Justification Graph valued. However, there will be a point where the area of woodland satisfies market demand, and any increase in quantity thereafter will not be as valued.
The quantity of woodland is considered to be the determining factor in amount of time produced and therefore changes in quantity of the A/U will be significant.

Quality
The relationship is considered to be +NL (major).
The quality of the A/U can affect the yield of timber. In a poor quality environment e.g. high levels of acidification, low nutrient cycling, tree growth will be poor and therefore limit yield. It is considered that the costs and effort in harvesting this poor growth would considerably outweigh the value, and in these circumstances it is considered that timber would not be harvested.
As the quality of the A/U increases, the potential for tree growth also increases. It may be possible to select the species that are grown, to select those with quickest growth rates. Improvements in material capital to harvest the timber will also increase the amount of output. However, there will be critical point where after further increases in quality will produce marginal benefits.

Quantity
The relationship is considered to be NL (major) (uncertain) No woodland is likely to mean a high level of run-off, erosion and soil failure which would have a significant negative effect on water quality. Benefits are gained quickly once some woodland is there (binding soils), with benefits slowing down once the woodland is planted.
Woodland provides a purification role by intercepting pollution, and reduces sediment inputs to watercourses (requirement to remove suspended sediment).
It is unclear how woodland effects the yield of water. It is likely that woodland would reduce the quantity of water available downstream through evapotranspiration, and indirect effect with water held by roots/interception of foliage with trees present. The effect on total yield is uncertain.
Given the uncertainty of the relationship, this has been A/U Benefit Characteristic Relationship Justification Graph upgraded to major and will therefore be taken forward for further consideration in the risk register.

Spatial configuration
The relationship is considered to be +NL (major).
The afforestation of uplands, which are a significant source of water (quantity) could adversely affect the amount of clean water obtainable. Afforestation in lowland areas, around towns, could act as interceptors to pollution before it reaches the watercourse.
The potential for spatial configuration of woodlands to affect clean water benefit (quality and quantity) is therefore considered to be significant.

W Clean air Quantity
The relationship is considered to be +NL (major).
Woodland can absorb pollutants internally or adsorb pollutants externally on to leaf and bark surfaces, and provides an overall role in production of 0 2 required for the air we breathe (UK NEA 2011).
As the quantity of woodland increases, the ability to clean air also increases, although this is most highly valued with the initial units of woodland. There is no critical mass with regard the potential for woodlands to clean air, and therefore this will keep increasing.

W Recreation Quantity
The relationship is considered to be +NL (major).
Woodland is listed as one of the most popular destinations for countryside visits (~250 million day visits per year) (UK NEA 2011, pg 268) It is assumed that all woodland could be replaced with another A/U therefore the value crosses the origin. The first units of woodland will be highly valued, however, at a critical amount i.e. enough woodland to satisfy recreational demands, any increases over this will not be as valued.

Spatial configuration
The relationship is considered to be +NL (major).
Only 55% of population have access to woods greater than 20ha within 4km, and 10% have access to woods greater than 2ha within 500m of their home (UK NEA 2011, pg 268) Woodland as recreational resource will be more valued when close to populations. However, there will be a certain distance which the majority of people will be happy to travel, and this will be highly valued, with anything closer being valued but with only marginal benefits.

W Aesthetics Quantity
The relationship is considered to be +NL (major).
It is assumed that all woodland could be replaced with another A/U therefore the value crosses the origin. The first units of woodland will be highly valued, however, at a critical amount i.e. enough woodland to satisfy recreational demands, any increases over this will not be as valued.

Quality
The relationship is considered to be +NL (major) There is some association between perceptions of landscape value and woodland characteristics: for example, woodland type (broadleaves tend to be more favoured than conifers), tree age (large, old trees tend to be favoured over young ones), openness (valued more than dense, closed areas) and diversity (mixtures and variation valued over uniformity) (Willis et al. 2003) (UK NEA, pg 269).
Ancient woodlands and veteran trees are historic features in their own right and provide a link to past society and culture (Rackham 2013). Many 'Royal Forests' have hundreds of years of history, tradition, myth and legend associated with them, helping to create important historic landscapes. Ancient woodland is also increasingly appreciated for its archaeological content.
The initial unit of woodlands will be valued, and as the quality improves, this will increase. However, after a certain level of improvements to the habitat, any additions are no longer as valued i.e. the marginal increase is less. Aesthetics = f [species (broadleaved vs coniferous, varied age structure); land; material capital (management practices -coppicing, felling)]

Spatial configuration
The relationship is considered to be +NL (major).
There is greater aesthetic value of woodlands where there are numerous plots in the landscape rather than a continuous belt. There is also considered to be greater value if people have views of woodland from their properties. Society has the potential to significantly influence the location of new woodland creation over the next 25 years.

Quantity
The relationship is considered to be +NL (major).
Woodland provides protection from flooding and soil failure by regulating the quantity of water downstream and stopping soil erosion.
Forests and woodland have long been associated with an ability to slow down run-off and reduce downstream flooding. There are three ways that trees can assist flood risk management; by reducing the volume of runoff, by promoting rainfall infiltration into the soil and reducing the rate of runoff, and by delaying the downstream passage of flood flows.
As woodland cover in a catchment increases, the avoided cost of protection will also increase. However, there will be a critical point after which any further increases in area A/U Benefit Characteristic Relationship Justification Graph will only have a marginal increase in benefits.

Spatial configuration
The relationship is considered to be +NL (major).
It is important to locate woodland in an appropriate area of the catchment to maximise influence on flooding, through interception of rainfall and regulate base flows.
Woodland in upland parts of the catchment are therefore considered optimal, whilst extensive areas on floodplains may be considered non-optimal due to the effect of water displacement.

W Wildlife Quantity
The relationship is considered to be +NL (major).
The quantity of the A/U can be changed, with the potential for all areas of woodland to be converted to a different land use. Assuming baseline quality of the A/U, the first unit will be highly valued, and this will continue to increase with the area of woodland. However, there will be a point where the area of woodland is sufficient, but the quality of the habitat will limit species diversity and abundance, and any increase in quantity thereafter will not be as valued.
The quantity will be important in determining the size of a population that can be supported i.e. carrying capacity. As the area increases, although only at the margins, there is potential to increase the abundance of species (note that quality is probably more important in determining the variety of species).

Quality
The relationship is considered to be +NL (major).
As the quality of the habitat increases, the potential to support a range of species and high abundance of species will increase. Improvements in diversity will be attributable to management e.g. coppicing and felling, dead log piles, as well as decreases in pollution and pests. A certain level of species diversity and abundance will be highly valued, however after this, increases in more specialised species or general abundance will be of lowering value.

Spatial configuration
This relationship is considered to be +NL (major).
With a higher connectivity of woodlands, the species diversity and abundance will increase. It is also possible to create woodland closer to people, and therefore the recreational and aesthetic value of wildlife could increase when in closer proximity to people.

Quantity
The relationship is considered to be +L (major).
Woodland is a carbon store, taking up and locking carbon dioxide through photosynthesis. With no woodland, there would be no benefit to equable climate. However, as the area of the woodland increases, the potential to store carbon would also increase (assuming wood is not used as a biofuel).

Wetlands
The relationship is considered to be +NL (major) Wetland habitats have a role in purification -they trap and filter particulates. Wetland systems, particularly reedbeds, have combinations of highly oxic and anoxic sites within their soils due to stratification in the sediment or soil profile and/or the release of oxygen from plant roots; these conditions are conducive to the breakdown and transformation of many pollutants including organic and inorganic compounds derived from agriculture and denitrification (a major mechanism for 'cleaning' groundwaters of their nitrogen content).
An increase in wetlands could therefore significantly improve clean water quality.

Quality
The relationship is considered to be +NL (major).

FW Recreation Quality
The relationship is considered to be +NL (major).
Quality can be affected by access restrictions e.g. reservoir not open to public, angling season reduced, low volume of water e.g. drought conditions which limits potential for kayaking etc, and water quality which could deter contact recreation e.g. swimming, angling, or habitat degradation which could restrict walking opportunities.
In degraded/poor environment (e.g. no water, no fish), there would be no recreation opportunities. As the quality of freshwater increases the value will also increase. However, this will only be up to a certain level of improvements and after this the marginal increase in value will become less. The relationship is considered to be +NL (major).
The degradation of habitats is considered to be of key importance when valuing the aesthetics e.g. heavily modified river channel vs natural meandering channel. As the quality of freshwater increases (i.e. naturalisation of the river channel improves) the value will also increase. However, this will only be up to a certain level of improvements and after this the marginal increase in value will become less. The relationship is considered to be +NL (major).
In a degraded/poor environment e.g. low permeability of floodplain, the avoided cost of flood protection will be low. However, as the quality increases, the avoided cost will A/U Benefit Characteristic Relationship Justification Graph also increase. At a critical point, further improvements will not significantly avoid costs of protection.

Spatial configuration
Wetland (incl. floodplain) The relationship is considered to be +NL (major).
Floodplains will be found next to their respective rivers, however their capacity to hold flood waters will be determined by the area available and connectivity with the river. Reservoirs with the aim of regulating flow will need to be optimally positioned in relation to the population they are protecting.
Therefore optimal positioning of the wetland and standing open water subcomponents will have a positive impact on avoided flood protection costs. This is considered to be significant.
The quantity will be important in determining the size of a A/U Benefit Characteristic Relationship Justification Graph population that can be supported i.e. carrying capacity. As the area increases, although only at the margins, there is potential to increase the abundance of species (note that quality is probably more important in determining the variety of species).

Wetlands
The relationship is considered to be +NL (major).
It is considered that you cannot significantly change the area of the A/U, just around the margins such as the wetland subcomponent. These changes in area will however, give rise to a significant change in wildlife value.

Rivers and streams Wetlands
The relationship is considered to be +NL (major).
As the quality of freshwater increases the value will also increase. However, this will only be up to a certain level of improvements and after this the marginal increase in value will become less.
The degradation of habitats is considered to be of key importance when valuing the wildlife benefit e.g. heavily

Spatial configuration
The relationship is considered to be +NL (major).
With a higher connectivity of freshwater habitats, the species diversity and abundance will increase. It is also possible to create some freshwater habitats closer to people, although limited e.g. new waterbodies, however it is considered that the recreational and aesthetic value of wildlife could increase when in closer proximity to people.

Wetlands
The relationship is considered to be +NL (major).
Natural England (2010) estimated that the remaining lowland fen in English peatlands stored 1,004-2,576 tonnes