PVA Assessment Including Berwick Bank
- When considering the impact during the breeding season on the regional population defined for the breeding season, using the most extreme NatureScot scenario (0.993 avoidance, 70% displacement and 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was 0.846 ( Table 11.101 Open ▸ ). The median population size was therefore projected to be 15.43% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 23.76. In terms of the population size, this means that the median of the impacted population fell within the 23rd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.995 ( Table 11.101 Open ▸ ) which translates to a median reduction of 0.46% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
Table 11.101: Gannet 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Breeding Season
- When considering the impact during the post-breeding season on the regional population defined for the post-breeding season, using the NatureScot scenarios (0.993 avoidance, 70% displacement and 1% to 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was 0.807 ( Table 11.102 Open ▸ ). The median population size was therefore projected to be 19.26% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 19.72. In terms of the population size, this means that the median of the impacted population fell within the 19th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that under a 70% displacement and 1% mortality rate alongside collision, the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. A percentile of 19 suggests that an adverse effect could occur. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.994 ( Table 11.102 Open ▸ ) which translates to a median reduction of between 0.59% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
Table 11.102: Gannet 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Post-breeding Season
- When considering the annual impact on the annual regional population, using the NatureScot Approach (0.993 avoidance, 70% displacement and 1% to 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was between 0.785 to 0.720 ( Table 11.103 Open ▸ ). The median population size was therefore projected to be between 21.46% to 27.98% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 15.80 to 9.64. In terms of the population size, this means that the median of the impacted population fell within the 15th and 9th percentile of the unimpacted population (a value of 50 would indicate that they are the same). Notably, the median of the impacted population fell close to the lower boundary, between the 15th and 9th percentiles of the unimpacted population. Whilst this is within the margin of error, this proximity suggests there could be an adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was between 0.993 to 0.991 ( Table 11.103 Open ▸ ) which translates to a median reduction of 0.67% to 0.91% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
- When considering the annual impact on the annual regional population, using the Applicant’s displacement rate and the NatureScot avoidance rates (0.993 avoidance, 70% displacement and 1% mortality) and with Berwick Bank included, the PVA predicted that the CPS was 0.785 ( Table 11.103 Open ▸ ). The median population size was therefore projected to be 21.47% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 15.88. In terms of the population size, this means that the median of the impacted population fell within the 15th percentile of the unimpacted population (a value of 50 would indicate that they are the same). Notably, the median of the impacted population fell close to the lower boundary of the 15th percentile of the unimpacted population. Whilst this is within the margin of error, this proximity suggests there could be an adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.993 ( Table 11.103 Open ▸ ) which translates to a median reduction of 0.67% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
Table 11.103: Gannet 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank on an Annual Basis
PVA Assessment Excluding Berwick Bank
- When considering the impact during the post-breeding season on the regional population defined for the post-breeding season, using the most extreme NatureScot scenario (0.993 avoidance, 70% displacement and 3% mortality) and with Berwick Bank excluded, the PVA predicted that the CPS was 0.814 ( Table 11.104 Open ▸ ). The median population size was therefore projected to be 18.58% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 20.56. In terms of the population size, this means that the median of the impacted population fell within the 20th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.994 ( Table 11.104 Open ▸ ) which translates to a median reduction of 0.57% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
Table 11.104: Gannet 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Excluding Berwick Bank during the Post-breeding Season
- When considering the annual impact on the annual regional population, using the Applicant’s Approach (0.993 avoidance, 70% displacement and 1% mortality) and with Berwick Bank excluded, the PVA predicted that the CPS was between 0.804 to 0.739 ( Table 11.105 Open ▸ ). The median population size was therefore projected to be between 19.56% to 26.08% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 18.56 to 11.08. In terms of the population size, this means that the median of the impacted population fell within the 18th and 11th percentile of the unimpacted population (a value of 50 would indicate that they are the same). Notably, the median of the impacted population fell close to the lower boundary, between the 18th and 11th percentiles of the unimpacted population. Whilst this is within the margin of error, this proximity suggests there could be an adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was between 0.994 to 0.992 ( Table 11.105 Open ▸ ) which translates to a median reduction of 0.60% to 0.84% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
- When considering the annual impact on the annual regional population, using the Applicant’s displacement rate and the NatureScot avoidance rates (0.993 avoidance, 70% displacement and 1% mortality) and with Berwick Bank excluded, the PVA predicted that the CPS was 0.804 ( Table 11.105 Open ▸ ). The median population size was therefore projected to be 19.57% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 18.44. In terms of the population size, this means that the median of the impacted population fell within the 18th percentile of the unimpacted population (a value of 50 would indicate that they are the same). Notably, the median of the impacted population fell close to the lower boundary of the 18th percentile of the unimpacted population. Whilst this is within the margin of error, this proximity suggests there could be an adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.994 ( Table 11.105 Open ▸ ) which translates to a median reduction of 0.60% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
Table 11.105: Gannet 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank on an Annual Basis
Magnitude of impact
- When considering both displacement and collision impacts in line with NatureScot guidance, there's a potential for double counting as a bird that is displaced cannot simultaneously experience collision. Therefore, it is likely that impacts provided within Table 11.99 Open ▸ to Table 11.100 Open ▸ are overestimates. As gannet experience around 70% displacement, collision numbers should be reduced by around 70%.
- Based on the combined displacement and collision assessment for the pre-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude
- Based on the combined displacement and collision assessment for the pre-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the pre-breeding season with Berwick Bank included and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results for the breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the breeding season with Berwick Bank included and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results for the post-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the post-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the post-breeding season with Berwick Bank included and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results, on an annual basis with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results, on an annual basis with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results, on an annual basis with Berwick Bank included and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the pre-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude
- Based on the combined displacement and collision assessment for the pre-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the pre-breeding season with Berwick Bank excluded and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on combined displacement and collision assessment results for the breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the breeding season with Berwick Bank excluded and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results for the post-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the post-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the combined displacement and collision assessment for the post-breeding season with Berwick Bank excluded and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results, on an annual basis with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 3% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results, on an annual basis with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate and a 70% displacement and 1% mortality rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Based on the PVA results, on an annual basis with Berwick Bank excluded and following the Applicant Approach using a 70% displacement and 1% mortality rate and using the NatureScot avoidance rate of 0.993, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude.
- Results from the PVA for the breeding, post-breeding season and annually concluded that the impact from the cumulative assessment with Berwick Bank included and excluded and following both the NatureScot and Applicant’s Approach was perceived as low.
- The cumulative effect is predicted to be of national spatial extent, long-term duration, continuous and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.
Sensitivity of the receptor
- Gannet were assessed as having low vulnerability to displacement impacts but higher vulnerability to collision impacts, and therefore considered to have medium vulnerability to the combined impact of displacement and collision.
- Gannet is a qualifying interest for several SPAs likely to be connected to the Array (within the mean-max + SD foraging range), with several non-SPA colonies also within range and so the species is considered to be of international value. Refer to Table 6.30 of volume 3, appendix 11.1 for details of SPAs with connectivity to the Array with regards to gannet.
- Gannet have low reproductive potential given a typical age of first breeding of five years and typically laying only a single egg per breeding season. However, although gannet has a low reproductive potential, the species has demonstrated a consistent increasing trend in abundance since the 1990’s (JNCC, 2020). It is of note that the species has suffered from the outbreak of HPAI during the 2022 breeding season (Pearce-Higgins et al., 2023), with declines of 25% recorded at certain sites in Britain in 2023 when compared against a pre-HPAI baseline (Tremlett et al., 2024). Therefore, whilst the overall population has shown steady growth, HPAI has led to some short-term declines. Therefore, overall gannet is deemed to have low recoverability.
- Gannet is deemed to be of medium vulnerability, medium recoverability and international value. The sensitivity of the receptor is therefore considered to be high.
Significance of the effect
- Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be high. The effect will, therefore, be of minor to moderate adverse significance. However, considering the pre-breeding, season mortality rates fell below 1%, along with the PVA results concluding there to be a low impact both with and without Berwick Bank and following both the NatureScot and Applicant’s Approach, it is considered that minor adverse significance is appropriate, which is not significant in EIA terms.
Further mitigation and residual effect
- No offshore ornithology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 11.10) is not significant in EIA terms.
11.13. Proposed Monitoring
- It is not appropriate to propose specific monitoring measures at this stage. Instead, the Applicant will engage with MD-LOT, NatureScot, and other relevant key stakeholders to identify and contribute to targeted and proportionate regional or strategic monitoring to better understand the environmental effects of offshore wind taking account of known evidence gaps. This may involve engaging and contributing to ongoing strategic initiatives from ScotMER forum (Scottish Government, 2024b). These measures will be agreed with key stakeholders and will be set out in a Project Environmental Monitoring Programme (PEMP).
11.14. Transboundary Effects
- A screening of transboundary impacts has been carried out and any potential for significant transboundary effects with regard to offshore ornithology from the Array upon the interests of European Economic Area (EEA) states has been assessed as part of the EIA. The potential transboundary impacts are summarised below:
- Disturbance and displacement from the physical presence of wind turbines and maintenance activities.
- Collision with wind turbines.
Disturbance and displacement from the physical presence of wind turbines and maintenance activities
- For all other species, disturbance and displacement was determined to result in minor adverse effect at worst case. As such, transboundary impacts, which encompass wider populations and those more distant from the Array, are not expected to occur. Therefore, transboundary impacts from disturbance and displacement from the physical presence of wind turbines and maintenance activities are determined to be negligible, which is not significant in EIA terms.
Collision with Wind Turbines
- For all species, collision with wind turbines was determined to result in minor adverse effect at worst case. As such, transboundary impacts, which encompass wider populations and those more distant from the Array, are not expected to occur. Therefore, transboundary impacts from collision with wind turbines are determined to be negligible, which is not significant in EIA terms.
Combined Impacts – Displacement and Collision with Wind Turbines
- For kittiwake, a potentially significant effect was identified as a result of the combined impact of displacement and collision. This potentially significant effect occurred during the breeding season when most birds found within the Array would be expected to be UK-breeding birds associated with colonies on the Scottish coast and Scottish islands. The impact caused to the annual population under the NatureScot extreme scenario is a direct result of breeding season impacts. However, it is important to note that there is likely doubling up of impacts, as displaced birds will not suffer collisions. Therefore, the impacts on kittiwake populations are overestimated. On that basis, this potentially significant impact has no potential to lead to a significant transboundary effect. For gannet, the combined impact was deemed to be minor at worst case. Therefore, transboundary impacts from combined impacts from displacement and collision with wind turbines are determined to be negligible, which is not significant in EIA terms.
11.15. Inter-Related Effects (and Ecosystem Assessment)
- A description of the likely inter-related effects arising from the Array on offshore ornithology is provided in volume 2, chapter 20.
- For offshore ornithology, the following potential impacts have been considered within the inter-related assessment:
- temporary habitat loss and disturbance;
- indirect impacts from construction/decommissioning noise;
- indirect impacts from UXO clearance;
- disturbance and displacement from the physical presence of wind turbines and maintenance activities;
- barrier to movement;
- collision with wind turbines;
- changes to prey availability; and
- entanglement.
- Table 11.106 Open ▸ lists the inter-related effects (project lifetime effects) that are predicted to arise during the construction, operation and maintenance, and decommissioning phases of the Array and also the inter-related effects (receptor-led effects) that are predicted to arise for offshore ornithology receptors.
- Effects on offshore ornithology are not expected to have secondary effects on other receptors.
Table 11.106: Summary of Potential Impacts for Offshore Ornithology from Individual Effects Occurring Across the Construction, Operation and Maintenance and Decommissioning Phases of the Array (Array Lifetime Effects) and From Multiple Effects Interacting Across all Phases (Receptor-led Effects)
11.16. Summary of Impacts, Mitigation, Likely Significant Effects and Monitoring
- Information on offshore ornithology within the offshore ornithology study area was collected through a desktop study and site-specific DAS. An assessment of the impacts resulting from the Array has been carried out using the methodology set out in section 11.9, in line with the guidance policy and legislation set out in section 11.4 and informed through the consultation process as described in section 11.5. This information is summarised in Table 11.107 Open ▸ and Table 11.108 Open ▸
- Table 11.107 Open ▸ presents a summary of the potential impacts, designed in measures and the conclusion of the magnitude of impacts in EIA terms in respect to offshore ornithology. The impacts assessed include:
- temporary habitat loss and disturbance;
- indirect impacts from construction/decommissioning noise;
- indirect impacts from UXO clearance;
- disturbance and displacement from the physical presence of wind turbines and maintenance activities;
- barrier to movement;
- collision with wind turbines;
- changes to prey availability; and
- entanglement.
- Overall, it is concluded that there will be no significant effects arising from the Array alone during the construction, operation and maintenance or decommissioning phase.
- Table 11.107 Open ▸ presents a summary of the potential impacts for the Array alone, designed in measures and the conclusion of LSE1 on offshore ornithology in EIA terms.
- The cumulative effects assessed include:
- disturbance and displacement from the physical presence of wind turbines and maintenance activities; and
- collision with wind turbines
- Overall, it is concluded that there will be the following significant cumulative effects from the Array alongside other projects/plans.
- significant adverse effect on kittiwake resulting from the combined displacement and collision with wind turbines impact when Berwick Bank is included.
- Table 11.108 Open ▸ presents a summary of the potential impacts from the Array cumulatively with other plans and projects, designed in measures and the conclusion of LSE1 on offshore ornithology in EIA terms.
- No likely significant transboundary effects have been identified in regard to effects of the Array.
Table 11.107: Summary of Likely Significant Environmental Effects, Secondary Mitigation and Monitoring of the Array Alone
Table 11.108: Summary of Likely Significant Cumulative Environment Effects, Mitigation and Monitoring