Identification of ecosystem services

Ecosystem services for inclusion within the NCA were selected from the long list presented within the ENCA Services Databook to provide confidence in a comprehensive consideration of potential natural capital impacts. Services were selected on the basis of the proposed scheme having a tangible impact on the capacity of habitats to deliver them. The selection process was hence an iterative one as the assessment developed and new evidence came to light as to the potential impacts of the scheme; in particular, as relevant chapters of the DMRB Stage 3 EIAR were reviewed to understand potential scheme impacts on natural capital.

The scoping table in Table 4‑1 details the ecosystem services considered for inclusion within the NCA and whether they were assessed in qualitative, quantitative or monetary terms. By default, all services scoped in have been considered qualitatively. Where possible, ecosystem services have been quantified and monetised permitting the availability of sufficient data.

Table 4‑1: Ecosystem service scoping table
Service type Ecosystem service Qualitative Quantitative Monetary Justification
Provisioning services Food production Yes No Yes Within the NCA boundary, there are parcels of both arable habitat and modified grassland, with the proposed scheme resulting in a loss of the former and gain in the latter. This impacts the capacity of land (natural capital) to support food production. Average farmland rents can be used as a proxy to understand the change in this value (more detail on this can be found in section 6.2).
Provisioning services Timber production Yes Yes Yes Coniferous woodland parcels with active felling licences are present within the DMRB Stage 3 Design Fix boundary for which yield forecasts can be obtained and valued. Assumptions have been made as to how land use change impacting these parcels, as a result of the scheme, will impact upon yields.
Provisioning services Water supply No No No The DMRB Stage 3 Road Drainage and the Water Environment chapter was reviewed. The assessment identified only one surface water supply abstraction from the River Tay relevant to the proposed scheme, an agricultural abstraction for irrigation. The residual significance of the impact on the abstraction is deemed only to be 'slight' and the magnitude 'negligible'. Impacts on water supply were thus scoped out of the NCA.
Regulating services Air pollutant removal Yes Yes Yes This service reflects the capacity for habitats to remove atmospheric pollutants and can be quantified and valued using average pollutant removal factors and corresponding unit values for human health benefits. Land use change as a result of the proposed scheme will cause changes in the composition of relevant habitats.
Regulating services Carbon reduction Yes Yes Yes Average sequestration and storage factors can be used to quantify the changes in the capacity for habitats to remove carbon from the atmosphere. This can be valued using central government carbon values for policy appraisal (values used can be seen in section 6.5). Land use change as a result of the proposed scheme will cause changes in the composition of relevant habitats.
Regulating services Flood regulation Yes Yes Yes Land use changes as a result of the proposed scheme will change the composition of habitats with a role in the storage of flood waters. Average storage rates and corresponding, average damage cost avoided and/or replacement values can be used to quantify and monetise the benefits, respectively.
Regulating services Noise reduction No No No An assessment into the capacity for vegetation to provide a buffer for receptors (residential properties) against road noise, and how this changes as result of the changes to habitats associated with the proposed scheme, was undertaken. Details of this assessment are provided in APPENDIX A. The assessment revealed no changes in this service and hence, it is scoped out.
Regulating services Pollination Yes Yes No Land use changes as a result of the proposed scheme will have an impact on the presence of habitats which are important for pollinator species. A bespoke, semi-quantitative (scoring) approach has been developed to understand the scale and direction of these impacts.
Regulating services Soil erosion protection Yes No No Habitat changes are anticipated which may decrease vegetation cover on slopes with the potential for affecting the risk of geotechnical hazards. These hazards will be considered within the specimen design and subsequent detailed design. In the absence of detailed soil and stability studies at this stage, quantification of such risks is not possible.
Regulating services Water purification No No No This reflects the role of habitats in preventing pollutants from entering watercourses and thus avoiding secondary damages. This service is most relevant to wetland habitats. The wetland habitats within the NCA boundary are wet woodland and blanket bog. Whilst wet woodland likely has a role in the regulation of local water quality, the area of wet woodland is not forecasted to be impacted by the proposed scheme. Furthermore, the blanket bog habitat is not proximal to a watercourse and thus deemed not to provide a service, nor will it change in area as a result of the proposed scheme. Hence this service has been scoped out.
Cultural services Education Yes No Yes This service reflects the capacity for the natural environment to provide learning opportunities and/or to support learning through its restorative functions. The proposed scheme could present an opportunity to create new geological features of interest through the necessary blasting and thus learning opportunities. The potential benefit is to be quantified for demonstrative purposes of the opportunity only and will not be included within the forecasted impacts of the scheme.
Cultural services Landscape and amenity Yes No No The proposed scheme has the potential to substantially impact natural assets, in particular woodlands and forests, which play a key role in the area's unique natural beauty and setting. Such cultural impacts are inherently subjective and thus difficult to quantify.
Cultural services Mental wellbeing No No No This service reflects the capacity of the natural environment to support the mental wellbeing of relevant populations through its restorative functions. Access to quality greenspace for this purpose is not expected to be significantly affected by the proposed scheme.
Cultural services Physical health No No No This service reflects the capacity for the natural environment to provide a setting for outdoor physical activity. Given the rural location, and thus high surrounding availability of quality greenspace, the proposed scheme is not deemed likely to have a tangible impact on access to space for outdoor activity.
Cultural services Recreation Yes No Yes The proposed scheme is anticipated to have impacts on local, destination greenspaces for outdoor recreation both in terms of access and the quality of recreational experience. The value of recreational experiences can be assessed using average Willingness To Pay (WTP) values applied to baseline visitor data. Baseline values can then be scaled to reflect the anticipated change in recreation values from a combination of changes to visitor numbers and/or recreational experience as a result of the impacts of the proposed scheme. There is insufficient data to accurately quantify the change in visitor numbers alone, however.
Cultural services Recreation (angling) No No No The DMRB Stage 3 Biodiversity chapter does not suggest that there will be any residual impacts on aquatic species. It is thus assumed that there are no tangible impacts to angling opportunities and hence this service is scoped out of the NCA.
Cultural services Volunteering Yes Yes Yes This service reflects the capacity for the natural environment to provide volunteering opportunities, which have secondary benefits in terms of upskilling, opportunities for social interactions and community cohesion. A wage equivalent for volunteer time can be used as a proxy for the minimum benefit received by participating individuals.