Outcomes

This section provides an overview of the key outcomes of the core and additional tasks.

Task Two: Natural capital baseline assessment

The primary outcome of Task Two was the development of a natural capital baseline which was used in subsequent tasks to understand the impact of the proposed scheme (pre- and post-mitigation).

In regards asset quantity, the ecosystem services afforded by the grassland and woodland environments were considered as the most prevalent across the study area, owing to the extent of habitat coverage.

The natural capital baseline assessment found that asset quality and location resulted in minor changes to the provision of ecosystem services, accordingly outcomes were largely driven by asset quantity.

Drivers/pressures and risks were identified by Task Two (with an overview provided in 'Natural capital drivers/pressures and risks').

Task Three: Scheme impacts on natural capital (pre-mitigation)

Task three found that 76% of habitats could be permanently lost because of the proposed scheme (pre-mitigation), with permanent losses of grassland, heath and woodland habitats anticipated. Furthermore, the ability of a further 16% of habitats to deliver ecosystem services could be temporarily compromised during construction.

Pre-mitigation, 60% of the inland surface water environment is subject to changes in natural capital and there is likely to be a temporary decrease in 39% of the inland surface water environment to provide ecosystem service provision during construction. Moreover, 43% of agricultural and cultivated land is estimated to be permanently lost, with 41% of agricultural and cultivated land being temporarily unable to provide ecosystem services during construction when compared to previous levels of provision.

  • 76% of habitats could be permanetly lost as result of proposed scheme (pre-mitigation)
  • Ability of 16% of habitats to deliver ecosystem services temporarily  compromised during construction
  • 60% of inland surface water environment subject to changes in natural capital
  • 39% decrease in inland surface water's ability to provide ecosystem services during construction
  • 43% of agricultural and cultivated land estimated to be permanently lost
  • 41% agricultural and cultivated land temporarily unable to provide ecosystem services during construction

Habitats impacted by the proposed scheme and the ecosystem services most associated with them are listed below. The ability of these habitats to provide these ecosystem services will likely be reduced because of the proposed scheme.

  • Inland surface waters: water quality regulation, flood regulation, erosion protection, cultural services, water support, fish production and pest control.
  • Grassland: food production, water supply, erosion protection, pollination, pest control and cultural services.
  • Heathland: water supply, erosion protection, pollination, pest control, flood regulation, carbon storage, air quality regulation, cooling and shading, noise reduction and cultural services. Impacts on ecosystem service provision will be dependent upon the sub-asset affected (i.e. bracken or scrub for example).
  • Woodland: woodland can provide all ecosystem services assessed within the retrospective natural capital assessment for the A9 Project 4 (apart from fish production) and therefore impacts on ecosystem service provision are likely to be significant.
  • Agriculture and cultivated: water supply, recreation, and food production.

Task Four: Effects of mitigation, compensation and enhancement, and development of a ‘balance sheet’

The outcomes presented in this section were developed prior to the later stages of the natural capital assessment and subsequent pilots (i.e. the ancient woodland pilot etc.). As such, there is some variation between the outcomes of Task Four and those of some of the proceeding sections. This is to be expected due to the iterative process adopted by the assessment.

Outcomes of task four identified that the provision of food production and air quality regulation post-delivery of the proposed scheme is reduced when compared to the baseline. All other ecosystem services see an increase in provision because of the proposed scheme and associated mitigation, bar fish production where no permanent impacts are identified.

The ecosystem services with the biggest rate of increase in provision include cultural services. However, it is recognised that the methodology for determining ecosystem service provision associated with natural capital assets indicates high values for cultural services, with the potential for many habitats to score highly across the five cultural services identified. Taking this into account, the following services see significant increases in provision:

  • pollination
  • erosion protection
  • water quality regulation
  • carbon storage, and
  • water supply.

The broad habitat types which benefit most from the proposed scheme include inland surface waters, grassland environments and woodland. This is again caveated by the fact that the spatial analysis does not assess loss of ancient woodland, more the losses and gains of woodland and associated ecosystem service provision. Heathland and agricultural environments are shown to be impacted adversely by the proposed scheme. It should be noted that the Environmental Statement captures and details agricultural losses alongside other areas of habitat loss.

Task Five: Identification of alternative mitigation, compensation, and enhancement measures

Task five identified several opportunities for natural capital enhancement, which are as follows:

  • Protection and enhancement of the heathland environment.
  • Enhanced air quality regulation provision.
  • Greater diversity of post-scheme habitats.
  • SuDS design (already nature-based) to be developed with a broader range of ecosystem service considerations in mind.
  • Enhanced consideration of trade-offs (inter- and intra-habitat). The underlying idea of trade-offs relative to natural capital is that gains in some ecosystem services can result in the loss of others. Similarly, whilst a gain in the grassland environment is achieved due to scheme mitigation, there are in fact losses in the grassland sub-habitat type ‘Neutral grassland – semi-improved’.
  • Opportunities for creating partnerships outside of the study area to enhance natural capital and ecosystem service provision (e.g. with owners of tourist hotspots and with Nature Scot to promote conservation of the freshwater pearl mussel).
  • Further enhancement of non-motorised user (NMU) provision (through additional signage and further promotion of active travel across communities and businesses).
  • Further hedgerow creation to promote biodiversity benefits and natural flood management (amongst other ecosystem services and opportunity for habitat connectivity).
  • Integration of green surfaces alongside the design of noise barriers to provide a wealth of ecosystem services. Green bridges and green walls could also be considered for integration.
  • Measures to further reduce and dispose of soilborne pests and diseases; animal and crop diseases; tree pests and diseases; and invasive species.
  • Transport Scotland’s soft estate provides the potential for significant ecosystem service provision if managed appropriately. Whilst remaining cognisant of maintenance and safety requirements, the potential to develop seed mixes for best natural capital and ecosystem service benefit could be considered.

It was recommended that consideration be made for future projects to adopt natural capital approaches alongside the development of the mitigation measures committed to in the Environmental Statement. This would allow for wider benefits and values to be identified, alongside the assessment and mitigation of adverse impacts.

It was also found that natural capital approaches should be integrated early within the development of a project. This would allow for natural capital considerations to inform and contribute to the design and development of the scheme.

Task Six: Capturing wider benefits (social value)

The social value mapping highlighted that the majority of the community benefit toolkit metrics/indictors are focused on the wider benefits of the A9 Dualling Programme that can be achieved through the procurement and employment process of the proposed scheme. Further social value could be achieved by continuing to use the metrics across the operation and maintenance phases of the proposed scheme.

The following community benefit toolkit metrics have the potential to be effectively implemented during operation and maintenance of the proposed scheme and therefore have the potential to generate additional social value:

  • Community metrics: Donations to local community projects and volunteer hours on local community projects
  • Employment metrics: All of the employment metrics could be continued through all phases of the Proposed Scheme
  • Poverty metrics: Initiatives to tackle homelessness and child poverty.

Overall, the community benefit toolkit metrics contribute substantial social value beyond the original purpose of the A9 Dualling Programme. It was recommended that these metrics are employed across Project 4 Pitlochry to Killiecrankie in order to achieve wider benefits and greater social value for the proposed scheme. It was also recommended that the metrics are considered across all phases (construction, operation and maintenance) of the proposed scheme.

Ancient Woodland Pilot

The Ancient Woodland Pilot found that extensive mitigation measures outlined in the Environmental Statement have protected much of the ancient woodland present across the study area; however, a significant area is still lost because of the proposed scheme.

Previous tasks identified that woodland was one of the broad habitat types that would benefit most from the proposed scheme. However, once ancient woodland is considered as an independent asset, the loss of ecosystem services becomes apparent and woodland can no longer be considered as a broad habitat to have benefitted from the proposed scheme (in the short-term, prior to reaching target condition).

Owing to the significant loss of ancient woodland, it is likely that the provision of the following ecosystem services will be impacted significantly.

  • flood regulation
  • erosion protection
  • carbon storage
  • air quality regulation
  • cooling and shading
  • noise reduction
  • pest control
  • recreation
  • aesthetic value
  • education
  • sense of place

Two key recommendations were made as a result of the ancient woold pilot, which should be taken forward by Transport Scotland and acknowledged across the wider discipline:

  • Ancient woodland should be considered as a discrete asset in natural capital assessments, independent from non-ancient woodland. Typically, an ancient woodland designation is used as an indicator of asset condition rather than a separate asset category.
  • An appropriate method of assessing the varying level of ecosystem service provision associated with ancient and non-ancient woodland should be applied for future natural capital assessments.

Historic Environment and Natural Capital Assessment Pilot

The Historic Environment and Natural Capital Assessment Pilot was included as a supplement to the Ancient Woodland Pilot as the two pilots are complimentary.

Key findings and recommendations from the Historic Environment and Natural Capital Assessment Pilot include:  

  • It is possible to use natural capital asset data alongside historic environment data to draw conclusions as to the contribution of the historic environment to natural capital assets and ecosystem service provision.
  • It is possible to identify time-depth in land-use, as piloted with woodlands surrounding the A9. This understanding of time depth in woodlands shows a pattern of historic land-use that influences both the preservation of heritage assets, which has implications for project planning and mitigation, and has implications for ecosystem service provision.
  • Natural capital assessments should involve assessment of the historic environment and cultural heritage.
  • Time-depth within a landscape is simple to assess in Scotland’s landscapes, and available data seems robust for woodlands (with tests on other habitat types proving promising).
  • Time-depth has implications for ecosystem service scoring, in terms of cultural (especially in relation to cultural heritage), provisioning, regulating, and supporting services.

Previously, the assessment of ecosystem assets has included quantity, quality, and location. However, considering the above findings and recommendations, future assessments could also include time-depth as a factor to assess ecosystem service provision. Alternatively, when considering ‘quality’, time-depth could be considered.

Future Transport Scotland projects which are looking to apply a natural capital approach should seek to understand the latest guidance from HES as to how the historic environment can be embedded within natural capital assessments.

Habitat Connectivity Pilot

It was found that functional connectivity was important for several ecosystem services within the study area, in particular services which involve the movement of organisms through the landscape (mainly relating to pollination and pest control). In addition, a network of accessible paths and spaces is important for the connectivity of people, and the cultural value of natural capital assets is heavily influenced by their accessibility for people.

Functional connectivity refers to the ability of different species to move from one patch of habitat to another based upon their ability to disperse through the land cover between them. How difficult it is for species to move between this intervening land cover is a key element in considering connectivity.

The pilot also found the following, which could provide a better understanding of the value of natural capital assets:

  • There could be an application of multipliers to methodologies used to determine ecosystem service provision associated with natural capital assets to better reflect the impact of habitat connectivity on ecosystem service provision. These will adjust the base scores depending on the level of functional connectivity, as well as connectivity for people.
  • Habitat connectivity may also be considered as a contributing factor of asset quality as habitat connectivity may build the resilience of natural capital assets and help to sustain the provision of ecosystem services in the long-term. Resilience refers to the ability of ecosystems to respond to disturbances, either by resisting them, recovering from them, or adapting to them, while retaining the ability to deliver ecosystem services (Natural Resources Wales. 2016. State of Natural Resources Report: Assessment of the Sustainable Management of Natural Resources. Technical Report). If a habitat is well connected and diverse, it is more resilient and less vulnerable to shocks/changes e.g. extreme weather events. Therefore, habitats with greater connectivity are less subject to degradation and adverse impacts on quality.
  • The spatial relationship between an asset and a specific feature within the landscape is a crucial consideration. As an example, a habitat may be more effective at regulating water quality if positioned between a source of pollution and a waterbody.

Understanding habitat connectivity can inform the placement of ecological mitigation to maximise biodiversity benefit. Using a natural capital lens can further shape the strategic placement of mitigation to deliver multiple benefits by also enhancing ecosystem service provision. An opportunity for enhancement for the A9 Project 4 could be the planting of heathland habitat within areas strategically located to improve habitat connectivity for people and biodiversity. 

Detailed Quantification and Valuation of Changes in Natural Capital Assets and Ecosystem Services

It was found that the initial overall impact, in partial monetary terms, of the proposed scheme on the provision of ecosystem services immediately following construction would be negative. However, the benefits derived from newly created habitat often develop over time as the habitat matures. Taking a more long-term perspective using total present values, it was found that proposed scheme will have a positive impact on the value provided by natural capital assets within the study area. This was based on the partial valuation of the following ecosystem services:

  • Air quality regulation
  • Carbon storage
  • Flood regulation
  • Food production
  • Water quality regulation
  • Wood production

Based on the approach taken, the most substantial losses in natural capital value came from the proposed scheme’s impact on air quality regulation and wood production through woodland clearance. However, these losses were outweighed by the likely carbon storage benefits of new areas of woodland planting for mitigation purposes. The findings of the detailed valuation broadly align with those of the previous Tasks.

Sensitivity analysis was used to demonstrate how natural capital assessments can inform the choice of mitigation measures by highlighting the trade-offs associated with different mitigation designs. This emphasises the need for a considered and holistic approach to valuation when making decisions regarding land-use change.  

On future schemes, natural capital assessments could look to ensure that mitigation is appropriately balanced across ecosystem services whilst still meeting regulatory requirements. This would be possible through demonstrating where there are trade-offs between different ecosystem services. That is to say, where losses in one service are being balanced out by gains in another, thereby hiding the true impact.