A9 Dualling Programme Strategic Environmental Assessment Non-Technical Summary
11. Biodiversity, Flora and Fauna
SEA Challenges/ Opportunities
A9 dualling presents a number of challenges and opportunities with respect to biodiversity and avoiding effects on protected sites and species.
The current route is considered to act as a barrier to some species movement, and dualling presents an opportunity to improve permeability across the route for mobile species, in terms of crossings, underpasses and culvert works, or specific species crossings where required.
SEA considers that the key issues relate to:
- limiting land take and habitat fragmentation;
- avoidance of designated sites and important/ sensitive habitats where possible;
- identifying opportunities to enhance links between habitats to minimise fragmentation and barriers to species movement.
SEA collated and considered a wide range of data on UK and internationally designated sites, ancient and semi-natural ancient woodland, national nature reserves and key species along the route.
The summary baseline table lists the number of sites, the area that they cover as a percentage of the full 200m online corridor and a percentage of the total feature area (i.e. where a recognised site/ feature is crossed by the corridor, the percentage of that site/ feature in the corridor).
The percentages are only used to provide an indication of the scale, but not the significance of the features along the corridor.
The wider area around the A9 and the National Park is particularly valuable for a wide range of flora and fauna species with some species either near the extent of their range, or limited to, the upland areas. However, only the key species noted were considered through the SEA in terms of identifying potential hotspots and issues for future design guidance. It should be noted that other species will also be considered through local level survey to inform later design stages.
| Feature type | No. of sites | % corridor | % feature |
|---|---|---|---|
| Ancient Woodland | 142 | 20% | 10% |
| Sites of Special Scientific Interest (SSSI) | 8 | 7% | 2% |
| Special Area of Conservation (SAC) | 7 | 5% | 1% |
| Special Protection Area (SPA) | 2 | 2% | 0.5% |
| National Nature Reserve | 2 | 1% | 6% |
| Ramsar | 1 | 1% | 2% |
| Key Species | |
|---|---|
| Capercaillie |
Qualifying interests for Kinveachy Forest SPA west of the A9, and Craigmore Wood, Anagach Woods, Abernethy Forest and Cairngorms SPAs east of the A9. Both Abernethy Forest and Cairngorms SPAs are, in places, less than 5km from Kinveachy Forest SPA and capercaillie may travel across the A9. |
| Deer | Found route wide with associated risk of accidents with vehicles, accident hotspots reported around Dunkeld-Birnam, Moy-Tomatin-Craggie sections |
| Otter | Found route wide with hotspots recorded around Bankfoot, Kindallachan, Dalnaspidal, Drumochter, Glen Garry, Kincraig, Insh Marshes, Kingussie, Dalmagarry, Daviot, Tomatin |
| Red Squirrel | Found route wide but with less activity recorded around Glen Garry, Pass of Drumochter, Glen Truim and Slochd-Tomatin |
| Wildcat | Areas of activity recorded around Carrbridge, east of Aviemore and around Newtonmore |
In terms of features with defined site boundaries, the SEA considers the site level issues within the online corridor and compares the online corridor option with the four near offline options in Sections A and B (discussed as A6, B2, B4, B5).
Ancient and Semi Natural Ancient Woodland
Route wide analysis shows that Ancient Woodland (AW) covers 20% of the total surface area of the 200m wide online corridor, with higher individual levels of cover in Sections A, B, E and F.
Semi-Natural Ancient Woodland (SNAW) covers 8% of the total 200m wide online corridor, with higher levels of cover in Sections B and E. In most cases, SNAW sites along the route are combined within AW sites.
SEA cannot determine the final route alignment within the 200m wide corridor, therefore it highlights that, cumulatively, 10% of the total area of the AW sites, and 27% of the total area of the SNAW sites, which cross the 200m corridor boundary, could be at risk of some impact.
The real area at risk will be much lower, as the majority of AW/ SNAW within a 200m corridor will be avoided, with works mainly restricted to edge clearance to enable widening around the existing route.
SNH advice is that edge effects (higher light intensity, reduced shelter and humidity) can extend up to 30m into a wood, effectively representing an increased loss of internal woodland habitat along a widened corridor. SNH advise that this is particularly significant in SNAW, where the severity of potential impacts should not be under-estimated.
Widening along the existing route is likely to present lower levels of risk to AW and SNAW, than near offline options. Online widening will increase the distance across the road between woodlands, with subsequent edge effects; however, near offline options could introduce additional fragmentation within woodlands.
When a wood is divided by a corridor, the effect is to create two smaller and generally isolated blocks of woodland. Such fragmentation will already have occurred along the length of the existing route and would be exacerbated by construction of new corridors through woodland.
SEA considers that online A9 dualling will likely result in minor losses at local levels around widened road boundaries. Taking into account the additional edge effects on internal woodland habitat, SEA finds that online dualling is likely to present, cumulatively, a moderate adverse effect on AW and SNAW.
Each of the near offline routes A6, B2, B4 are assessed as presenting major adverse effects, in terms of additional habitat fragmentation.
In terms of the avoidance and/ or minimisation of AW and SNAW habitat fragmentation, SEA assesses all near offline options, other than Option B5, as less favourable than the online corridor.
Similarly, local minor adverse secondary effects are likely for species, in terms of a widening of the current infrastructure barrier between woodlands, raised to locally major adverse effects should any new routes be cut through woodlands.
SEA considers that local level mitigation in terms of pipes, tunnels, culverts, rope bridges between higher trees, and pedestrian subway crossings will improve permeability and connectivity across the road structure, reducing the severity of secondary adverse barrier effects.
More detailed route alignment studies will be supported by local habitat surveys which should identify and consider the ecological value of the particular AW and SNAW site areas at risk.
In areas where AW and SNAW are unavoidable via route alignment studies, potential impacts should be minimised by limiting the widened footprint of the road as far as possible, and considering the flexibility to locate lay bys (and other footprint widening features) outwith designated woodland boundaries.
Where land take from woodland is unavoidable appropriate mitigation and restoration plans will be required.
Natura 2000 (SAC/ SPA) & Ramsar Sites
Special Areas of Conservation (SAC) are designated under the European Habitats Directive, Special Protection Areas (SPA) are designated under the European Birds Directive and Ramsar sites are internationally important wetland areas, designated under the Ramsar Convention.
In order to ensure effective assessment of potential effects on Natura and Ramsar sites, a Habitats Regulations Appraisal (HRA) Screening is running in parallel with the SEA. HRA Screening aims to identify internationally designated sites where A9 dualling could present likely significant effects (LSE) on qualifying interest features or the conservation objectives of the site.
Where the potential for LSE is identified, then a programme level Appropriate Assessment needs to be undertaken for each site. The HRA Screening Report has been submitted for consultation with SNH; however, at this point the Screening exercise found that A9 dualling has the potential to present Likely Significant Effects (LSE) on the:
- River Tay SAC;
- Tulach Hill and Glen Fender Meadows SAC;
- River Spey SAC;
- River Spey - Insh Marshes SPA/ Ramsar site;
- Insh Marshes SAC; and
- Drumochter Hills SPA and SAC.
Each of these sites will be examined further through strategic programme level Appropriate Assessment (AA) to consider a range of dualling related issues, and determine effective strategic mitigation recommendations, which will be captured and incorporated via the SEA Post Adoption Statement.
SNH feedback may recommend the inclusion of additional sites.
Online Corridor vs. Near Offline Options
Option A6 would require at least two additional crossings of the River Tay SAC in new areas. The potential impact of works in new, presently less disturbed/ engineered areas, has the potential to present greater risks of LSE than the online corridor, making Option A6 less favourable.
Option B2 lies fully within the Tay flood plain (a wider area than the SAC boundary) and would require a large crossing in the vicinity of the Shingle Islands SAC. In the context of other constraints, SEA considers this option less favourable than the online corridor.
Option B4 provides an alternative route around Pitlochry and the Killiecrankie Battlefield site; however, this Option is likely to present higher risk of LSE in terms of the River Tay and Tullach Hill and Glen Fender Meadows SACs. SEA considers that Option B4 is therefore less favourable than the online corridor.
Option B5 straightens some bends in the current route at the northern end of the Tulach Hill site, creating additional distance between the road and the River Tay SAC for the majority of the Option length. SEA considers that, in terms of the River Tay SAC only, this Option might be favourable when compared with the online corridor.
SEA considers that dualling has the potential for major adverse effects on the Drumochter Hills and Insh Marshes sites, and minor adverse effects on the other noted designated sites.
SEA recommends a workshop with SNH, SEPA and the Cairngorms National Park Authority (CNPA), during the SEA Environmental Report consultation period, to inform a strategic level Appropriate Assessment (AA) and the development of suitable guidance for later design stages around the Tay, Spey, Tulach Hill and Glen Fender Meadows, Drumochter Hills and Insh Marshes designated Natura and Ramsar sites.
Sites of Special Scientific Interest (SSSI)
There are no biological or mixed SSSI identified within the 200m corridor in Sections A or F. In the other sections, the 200m wide online corridor crosses the boundaries of eight SSSI sites designated for biological features.
The online corridor option in Section B presents the potential for major adverse effects at the site level on the Aldclune and Inverack Meadows SSSI, should the preferred route alignment encroach upon, and require land take from within the site.
Near offline Option B2 would be likely to present greater risks to the Shingle Islands SSSI, as a crossing would be required around one of the island locations. SEA considers Option B2 as less favourable than the online corridor.
Option B4 presents significantly higher risk to the Pass of Killiecrankie SSSI, designated for upland oak woodland, as this Option would cut directly through the site. Option B4 would also likely present a higher level of risk to the Tulach Hill SSSI. SEA considers Option B4 as less favourable than the online corridor.
However, Option B5 actually presents lower risks to the Aldclune and Inverack Meadows SSSI, as it straightens the bends on the A9 that border the site boundaries. SEA considers that, in terms of the Aldclune and Inverack Meadows SSSI only, this Option might be favourable when compared with the online corridor.
SEA considers that the majority of SSSI sites within the 200m online corridor are avoidable via route alignment studies, either by widening to the opposite side of the carriageway, or minimising the dualling footprint in the narrower area around Craigellachie, which would result in no significant adverse effects.
Should route alignment studies prove unable to avoid encroaching on the Craigellachie site, in Section E, any land take should be minimised and would require consultation with SNH to determine appropriate mitigation measures.
Land take from the SSSI would be minimal; however, as it would represent permanent loss within a national site, it could present potentially major adverse effects at the site level, depending on the sensitivity of the habitats/ species affected.
Strategic mitigation measures developed under the strategic Appropriate Assessment for the Tulach Hill, Drumochter Hills and Insh Marshes Natura and Ramsar designations will be designed to result in no LSE for the qualifying interest features of the Natura designations.
SEA will ensure that corresponding features of the SSSI designations on these sites are equally considered.
Given that the Drumochter Hills SSSI has different boundaries than the SAC/ SPA designations, there remains some risk of potentially major adverse effects at the site level.
Detailed local environmental survey and assessment will be required to inform A9 dualling route alignment studies through the Drumochter Hills SSSI site, to ensure that the overall footprint width is minimised, that SSSI features are identified and avoided wherever possible, and that effective site level mitigation is agreed with SNH.
This would likely reduce the risk of residual environmental effects to moderate or minor adverse effects at the site level.
National Nature Reserves (NNR)
The A9 runs alongside two NNR sites in Section E; Insh Marshes and Craigellachie.
With respect to the Craigellachie NNR, the site is at a higher elevation than the A9, as the road wraps around the hillside. The area between the NNR site and built features on the opposite side of the A9 is narrow, closing to 40-50m at some points.
SEA recognises this potential pinch point in Section E; however, SEA considers that there is sufficient clearance around the current single carriageway to avoid encroaching on the site, which would result in no significant adverse effects.
Should route alignment studies prove unable to avoid encroaching on this site, any land take should be minimised and would require consultation with SNH to determine appropriate mitigation measures.
Land take from the NNR would be minimal; however, as it would represent permanent loss within a national site, it could present potentially major adverse effects at the site level, depending on the sensitivity of the habitat/ species affected.
Detailed route alignment studies should seek to avoid encroaching upon the NNR site boundary; however, in the event that does not prove feasible, the supporting local level EA should consider appropriate mitigation measures in consultation with SNH.
Strategic mitigation measures developed under the strategic AA for the Insh Marshes Natura and Ramsar designations will be designed to result in no LSE for the Natura designations.
SEA will ensure that these equally result in guidance to avoid significant adverse effects to the Insh Marshes NNR.
Consideration of Key Species
The general consideration for key species is the likely effect A9 dualling could have on habitat loss or fragmentation, and species movement across the road, i.e. whether dualling will present additional barrier effects and mortality risks.
The SEA discusses the potential issues around dualling on woodland habitat, barrier effects of road widening, opportunities around drainage, SUDS and culverts improving connectivity, as well as issues around grade separated junctions, pedestrian subways and deer fencing.
SEA considers that online dualling will present minor adverse effects at the local level, in terms of the potential for woodland edge clearance and associated habitat loss and barrier effects.
Dualling could equally provide locally minor beneficial effects by improving permeability through the route for species.
SEA considers that local level ecological surveys, environmental and geotechnical assessment, undertaken in accordance with DRMB and best practice, will inform route alignment studies to avoid and minimise potential adverse effects.
Further survey will be required at the preferred route alignment detailed design stage; and detailed management plans including appropriate mitigation measures, working method statements, and achievable restoration plans will be required for approval by SNH at the project level.