Publication - Publication

Offshore wind energy - draft sectoral marine plan: habitat regulations appraisal

Published: 18 Dec 2019
Directorate:
Marine Scotland Directorate
Part of:
Energy, Marine and fisheries
ISBN:
9781839603754

The habitats regulations appraisal is completed in accordance with the Habitats Regulations that implement the EC Habitats and Birds Directives in UK waters and has been completed for the sectoral marine plan for offshore wind.

Contents
Offshore wind energy - draft sectoral marine plan: habitat regulations appraisal
9 Potential for Adverse Effects on the Otter Feature

9 Potential for Adverse Effects on the Otter Feature

9.1 Introduction

9.1.1 Following the screening process, a total of 468 European/Ramsar sites were identified for which there is a LSE (or the potential for a LSE cannot be excluded) (Table C1).  Of these sites, 44 SACs were identified where it was not possible to conclude that there would be no LSE from the Sectoral Offshore Wind Plan for qualifying otter interest features.

9.1.2 Given the broad area covered by the Sectoral Offshore Wind Plan and the large number of sites screened into these assessments, the same method as agreed in previous plan-level HRAs [327] [328] [329] was used i.e. it is not necessary to individually review the full list of all sites and the qualifying otter interest features that they support within this report. The individual sites that were screened in for each of the 17 DPOs are shown in the schedules (Tables D1-D17) and on the maps (Figures E1-E17).  Locations of the SAC and Ramsar sites that are screened in for qualifying otter interest features are provided in Appendix F (Figure F9).

9.1.3 Some of the SAC and Ramsar sites also contained other interest features for which it could not be concluded that there is no LSE (e.g. supralittoral habitats) and these are reviewed separately under the relevant section(s) encompassing these other habitat/species groups.  Where there were interest features at these sites which have been ‘screened out’ because there will be no LSE then these were recorded (see Table C1).

9.1.4 In summary, the screening phase concluded that there is a possibility of a LSE (or that it was not possible to conclude no LSE) for otter Lutra lutra (1355). To assess whether there is any adverse effect on the integrity of the relevant European/Ramsar sites, the following sections review the sensitivities of the associated otter interest feature, identify the conservation objectives and assess, in tabular format, the effects arising in the context of the proposed plan-level mitigation measures.

9.2 Sensitivities of the Otter Interest Feature to Sectoral Offshore Wind Plan Activities

9.2.1 This section reviews the sensitivities that are relevant for the otter interest feature.  Initially a generic review of the sensitivities is presented under the impact pathways identified during the screening phase:

  • Physical Loss/Gain of Habitat (Loss of Foraging Habitat);
  • Physical Damage to Habitat (Damage to Foraging Habitat); and
  • Non-Physical Disturbance (Noise/Visual Disturbance causing Barrier and Exclusion effects).

9.2.2 Following this review, the general sensitivities for otter are identified and tabulated in addition to the impact pathways.

9.3 Physical Loss/Gain of Habitat (Loss of Foraging Habitat; Impact Pathway 2)

9.3.1 Based on SNH advice about the impacts of development on otter [330] as well as the relevant advice documents provided by SNH under Regulation 33(2) of the Conservation (Natural Habitats, &c.) Regulations 1994 (as amended), it is evident that otter are vulnerable to the loss of their shelters (including those on the shoreline) and to the loss of habitat which, in turn, can leave them more exposed to disturbance effects.  If shore development overlaps with otter habitat it may result in direct loss of foraging habitat, removal of holts and loss of resting places (couches).

9.4 Physical Damage to Habitat (Damage to Onshore Habitat; Impact Pathway 6)

9.4.1 Shore development, including cable alignments and landfall related to the Draft Plan have the potential to damage foraging areas either directly or indirectly.

9.4.2 When assessing the impacts of construction work, the sensitivities of otter to habitat damage are gauged by the presence or absence of otter activity (e.g. spraints) and, in particular, by evidence of otter shelters, as it is usually these which ultimately constrain a development in terms of licensing.  The scope of the proposal, allied to the level of otter activity, dictate the potential risks that exist.  However, even relatively small-scale developments, such as bridge repairs or bank works, have the potential to damage otter habitat and cause disturbance.

9.5 Non-Physical Disturbance (Noise/Visual Disturbance Causing Barrier and Exclusion Effects; Impact Pathways 10 and 11)

9.5.1 Otter are sensitive to visual and noise disturbance. They are intolerant of areas subject to intense human activity, such as recreational areas [331]. Noise and visual impacts associated with coastal engineering works may exclude otter from foraging habitat.

9.5.2 Otter move along established routes between open-water habitats, including freshwater sites near the coast, therefore they are sensitive to any proposals that could cause a barrier to their established pathways.

9.6 Otter Sensitivity Review

9.6.1 Table 19 shows the sensitivities of, and the activities that might affect the otter interest feature.  The impact pathway descriptions are taken directly from the generic descriptions in Table 2.

Table 20: Potential sensitivities of otter to the Sectoral Offshore Wind Plan

Sensitivity Category Sensitivities Pathway Ref. No. Leasing Activity as Identified in Sectoral Offshore Wind Plan HRA (Summary Impact Pathway Description) Survey Construction Operation Decommission
PLG Physical Loss/Gain of habitat 2 Loss of foraging areas from reduction in coastal and offshore habitat due to installation of devices and cable armouring both at the development footprint and outside these areas from associated scour and indirectly from changes to the hydrodynamic regime, as well as from chains anchoring devices disturbing seabed habitat during operation. No impact  No impact  MS No impact 
PD Physical Damage to habitat 6 Reduction in quality of foraging areas as result of damage to coastal and offshore habitat from baseline surveys (e.g. boreholes and trawls); from equipment use causing abrasion, damage or smothering during installation; from maintenance and removal of cables/devices or from scour, sediment transport and hydrodynamic change, and damage from chains anchoring devices during operation. No impact  LMS LS LMS
NPD Non-Physical Disturbance 10 Visual disturbance and exclusion from areas as a result of surveying, cable and device installation/operation and decommissioning activities and movements of vessels. LS LS LS LS
NPD Non-Physical Disturbance 11 Noise/vibration disturbance and exclusion from areas as a result of vessels and other activities during survey work (e.g. seismic exploration and geophysical surveys), construction (e.g. piling, drilling, cable laying), operation (e.g. device noise), maintenance or decommissioning. LS LS LS LS
In this table, only the estimated sensitivity levels are shown. The level of risk will be dependent upon exposure.  For instance, there would be a high degree of exposure for otter were a development to occur within or near to a European/Ramsar site.  However, at the present time, there is uncertainty regarding the degree of exposure and a worst-case assumption has been made.
LS: Low Sensitivity
LMS: Low to Medium Sensitivity
MS: Medium Sensitivity
HS: High Sensitivity

9.7 Potential Effects on European/Ramsar Sites of the Sectoral Marine Plan

9.7.1 The following sections review the conservation objectives for this feature and the potential effects arising for each of the European/Ramsar sites.

9.7.2 The conservation objectives for the qualifying otter interest features seek to avoid deterioration of the habitats and significant disturbance to otter, thus ensuring that the integrity of the site is maintained and the site makes an appropriate contribution to achieving favourable conservation status for this qualifying feature. The conservation objectives are to ensure for the qualifying species that the following are maintained in the long term:

  • Population of the species as a viable component of the site;
  • Distribution of the species within site;
  • Distribution and extent of habitats supporting the species;
  • Structure, function and supporting processes of habitats supporting the species; and
  • No significant disturbance of the species;

9.7.3 Taking account of the conservation objectives and the plan-level activities to which the otter interest feature is sensitive, this section reviews the effects of the Sectoral Offshore Wind Plan on the integrity of the European/Ramsar sites.  The results are presented in Table 20.

Table 21: Assessment of the potential effects of the Sectoral Offshore Wind Plan on the otter interest feature

Screened-in sites with these qualifying features are provided in Table C1 (Appendix C) Is There an Adverse Effect on Integrity of any European/Ramsar sites? Is There an Adverse Effect on Integrity
With Additional Mitigation Measures?
Qualifying and Supporting Feature Summary Impact Pathway  Pathway Ref. No.  Sensitivity Level(s) Commentary, and Relevant Conservation Objective
  • Otter

Physical Loss/Gain of Habitat

Loss of foraging areas from reduction in coastal and offshore habitat due to installation of devices and cable armouring both at the development footprint and outside these areas from associated scour and indirectly from changes to the hydrodynamic regime, as well as from chains anchoring devices disturbing seabed habitat during operation.

2 Sensitivity Level(s) considered to be medium (see Table 19 for detail and colour code) Possibility of an adverse effect on integrity Further work would be required at project-level to ascertain LSE. However, in advance of considering mitigation measures, it cannot be concluded that there will be no AEOI on any European/Ramsar sites. This is because of the inherent uncertainties such as:
  • the detail of the Plan implementation process;
  • future generation capacities;
  • the location, scale and densities of development;
  • the proposed technologies to be used and future advances in these technologies;
  • the scale of the effects arising via some of the defined impact pathways; and
  • the efficacy of some project-level mitigation options.  
No adverse effect on integrity With the application of appropriate and meaningful mitigation measures to accompany the Plan (see Section 11), there will be no AEOI.
Commentary/Risk Review
The potential effects to otter habitat arising from any coastal activities (i.e. cable routeing and landfall) will be highly dependent upon the locations selected, the scale of the work proposed and the proximity of the works to their holts and sheltering grounds.  In advance of a full understanding about the exposure levels, the sensitivity of this species to this effect is considered to be medium.
Relevant Conservation Objectives (see Section 9.7 Of the conservation objectives, the following are particularly relevant to this impact pathway:
  • Distribution and extent of habitats supporting the species; and
  • Structure, function and supporting processes of habitats supporting the species.
  • Otter

Physical Damage

Reduction in quality of foraging areas as result of damage to coastal and offshore habitat from baseline surveys (e.g. boreholes and trawls); from equipment use causing abrasion, damage or smothering during installation; from maintenance and removal of cables/devices or from scour, sediment transport and hydrodynamic change, and damage from chains anchoring devices during operation.

6 Sensitivity Level(s) considered to be low to medium (see Table 19 for detail and colour code) As above As above
Commentary/Risk Review
The extent to which habitat supporting otters will be damaged as a result of cable installation activities is largely dependent on the proximity of the works to their holts and sheltering grounds.  In advance of a full understanding about the exposure levels, the sensitivity of this species to this effect is considered to be low to medium.
Relevant Conservation Objectives (see Section 9.7 Of the objectives, the following are particularly relevant to this impact pathway:
  • Distribution and extent of habitats supporting the species; and
  • Structure, function and supporting processes of habitats supporting the species.
  • Otter

Non-physical Disturbance

Visual disturbance and exclusion from areas as a result of surveying, cable and device installation/operation and decommissioning activities and movements of vessels

10 Sensitivity Level(s) considered to be low (see Table 19 for detail and colour code) As above As above

Commentary/Risk Review
The degree to which otters from locations within a European/Ramsar site will be subject to visual disturbance from survey and construction activities will largely be a function of the proximity of such works to their holts and foraging grounds.  Most European/Ramsar sites which support otter are inland from the coast and, therefore, the likelihood of visual disturbance is considered to be low.

The guidance on undertaking surveys to assess impacts upon this species suggests that distances of 200-250m are appropriate.  It is noted [332] that for ‘small’ schemes such as individual bridges, pipeline crossings, local bank works and individual houses, a survey of 200-250m both upstream and downstream of the site is recommended, but with particular attention being paid to important riverine features such as in stream islands and reed beds.  Beyond about 250m, disturbance from the proposed activity is unlikely to be an issue.  It is expected that there are unlikely to be adverse disturbance on otter beyond these distances along the shoreline.

Relevant Conservation Objectives (see Section 9.7 Of the conservation objectives, the following are particularly relevant to this impact pathway:
  • Population of the species as a viable component of the site;
  • Distribution of the species within site; and
  • No significant disturbance of the species.
  • Otter

Non-Physical Disturbance

Noise/vibration disturbance and exclusion from areas as a result of vessels and other activities during survey work (e.g. seismic exploration and geophysical surveys), construction (e.g. piling, drilling, cable laying), operation (e.g. device noise), maintenance or decommissioning.

11 Sensitivity Level(s) considered to be low (see Table 19 for detail and colour code) As above
As above

Commentary/Risk Review
The degree to which otters from locations within a European/Ramsar site will be subject to noise disturbance from survey and construction activities will largely be a function of the proximity of such works to their holts and foraging grounds.  Most European/Ramsar sites which support otter are inland from the coast and, therefore, the likelihood of noise/vibration disturbance is considered to be low.

The guidance on undertaking surveys to assess impacts upon this species suggests that distances of 200-250m are appropriate.  It is expected that there are unlikely to be adverse disturbance on otter beyond these distances along the shoreline.  

Relevant Conservation Objectives (see Section 9.7 Of the conservation objectives, the following are particularly relevant to this impact pathway:
  • Population of the species as a viable component of the site;
  • Distribution of the species within site; and
  • No significant disturbance of the species.

Contact

Email: drew.milne@gov.scot