Change in natural capital assets
A natural capital asset register was also developed for a post-development scenario for the proposed scheme. As per the baseline, this was taken from the DMRB Stage 3 Design Fix SBMT, compiling the On-Site retained, enhanced and created habitat areas.
The landscape and ecology planting proposals were used to inform the post-development habitats for the proposed scheme within the SBMT. It should be noted that surplus to the landscape and ecology proposals used, additional areas will be required for the compensation of woodland. Additional areas will also be considered for enhancement opportunities. Work has been undertaken and is ongoing to develop said offsite enhancements. A desk study was undertaken to identify local initiatives that could offer a way of delivering enhancements for the proposed scheme. Consultation with Forestry Land Scotland, Atholl Estates and Murthly Estates was also undertaken to identify opportunities for enhancements within land adjacent to the proposed scheme. Further consultation will be undertaken to identify additional off-site areas for enhancement as required.
As offsite enhancements have not been included within the SBMT for the DMRB Stage 3 Design Fix, they are not accounted for within the NCA. As such, the outcomes for the proposed scheme within the NCA are likely to significantly underestimate the potential benefit or, vice versa, overestimate any adverse outcomes for ecosystem services.
Table 3‑1 presents the change in area for each habitat type within the proposed scheme. Note that Retained areas represent those which would be retained during construction and, therefore, do not constitute a change. Temporary habitat losses associated with construction have been accounted within SBMT data.
As discussed, the natural capital asset register reflects a post-development scenario where there are some notable losses of woodland, mostly coniferous: deciduous woodland area increases overall by nearly 15ha, whilst there is a loss of almost 28ha of coniferous woodlands (inclusive of Scot’s pine). There is a large increase in the coverage of other neutral grassland. Over 65% of bracken habitat is lost along with the majority of arable habitat.
| Habitat type | Baseline - Area (ha) | Retained - Area (ha) | Enhanced/Created - Area (ha) | Change - Area (ha) | Percentage change (%) |
|---|---|---|---|---|---|
| Other coniferous woodland | 44.78 | 18.35 | 0.00 | -26.43 | -59.02 |
| Other woodland; mixed | 41.02 | 24.89 | 17.78 | 1.65 | +4.01 |
| Lowland mixed deciduous woodland | 24.07 | 14.72 | 30.38 | 21.02 | +87.34 |
| Other neutral grassland | 22.07 | 6.74 | 25.50 | 10.18 | +46.12 |
| Other woodland; broadleaved | 12.98 | 5.24 | 0.02 | -7.73 | -59.51 |
| Developed land; sealed surface | 12.97 | 8.78 | 19.69 | 15.50 | +119.47 |
| Modified grassland | 9.03 | 0.70 | 9.94 | 1.61 | +17.83 |
| Other scot's pine woodland | 7.21 | 5.95 | 0.00 | -1.26 | -17.45 |
| Bracken | 6.12 | 2.11 | 0.00 | -4.01 | -65.48 |
| Upland heathland | 4.63 | 2.37 | 0.00 | -2.25 | -48.68 |
| Wet woodland | 4.12 | 4.12 | 0.00 | 0.00 | 0.00 |
| Blanket bog | 3.43 | 3.43 | 0.00 | 0.00 | 0.00 |
| Non-cereal crops | 2.85 | 0.00 | 0.00 | -2.85 | -100.00 |
| Gorse scrub | 2.72 | 1.31 | 0.00 | -1.41 | -51.68 |
| Temporary grass and clover leys | 2.69 | 0.00 | 0.00 | -2.69 | -100.00 |
| Cereal crops | 2.08 | 1.05 | 0.22 | -0.81 | -38.87 |
| Lowland heathland | 1.87 | 1.64 | 0.00 | -0.23 | -12.35 |
| Vegetated garden | 1.63 | 0.10 | 0.00 | -1.53 | -93.80 |
| Other lowland acid grassland | 1.29 | 0.06 | 0.00 | -1.24 | -95.74 |
| Lowland beech and yew woodland | 0.79 | 0.79 | 0.00 | 0.00 | -0.03 |
| Other inland rock and scree | 0.70 | 0.33 | 0.74 | 0.37 | +52.49 |
| Mixed scrub | 0.53 | 0.00 | 0.65 | 0.12 | +22.64 |
| Artificial unvegetated, unsealed surface | 0.46 | 0.20 | 0.00 | -0.26 | -56.40 |
| Purple moor grass and rush pastures | 0.09 | 0.09 | 0.00 | 0.00 | 0.00 |
| Lowland dry acid grassland | 0.04 | 0.04 | 0.00 | 0.00 | 0.00 |
| Built linear features | 0.04 | 0.04 | 0.00 | 0.00 | -0.01 |
| Ruderal/ephemeral | 0.00 | 0.00 | 2.24 | 2.24 | Not Applicable |
| Rural tree | 0.00 | 0.00 | 1.62 | 1.62 | Not Applicable |
Assumptions and limitations
Ancient woodland has been excluded from the SBMT calculations, and thus the NCA, as it is categorised as an irreplaceable habitat. It is understood that there are some ancient woodland losses associated with the proposed scheme and whilst the significance of the potential impacts on natural capital will be somewhat mitigated by the bespoke compensation required, this is recognised as a limitation of the assessment.
As discussed in Section 3, a number of offsite habitat measures could not be captured within the current NCA. This includes additional (ancient) woodland compensation required, which is considered separately due to ancient woodland being irreplaceable habitat (as above) and planned offsite biodiversity enhancements, which have not been confirmed, and thus insufficient data was available for their inclusion within the SBMT for the DMRB Stage 3 Design Fix. It is assumed that once offsite habitat measures have been confirmed and were these be able to be accounted for within the NCA, the outcomes of the NCA would be notably improved.