Abstract
Large-scale offshore wind farm (OWF) developments have the potential to interact with benthic species and habitats of conservation importance. The expansion of offshore wind in English waters will increase the cumulative risk of adverse effects on the integrity of protected sites and species populations in the UK. It may also not be possible to avoid or mitigate against adverse effects on designated sites. Under these circumstances, the provision of compensatory measures will be required, where a project is consented in the knowledge that the overall coherence of the Marine Protected Area (MPA) network is maintained.
This project aims to identify benthic habitats that, whilst not classified as the same, have a similar or identical ecological function and ecosystem service provision to one another. Should it not be possible to rule out an adverse effect on one designated site/feature, it may be possible to consider habitats identified as similar for the delivery of compensatory measures. This work is intended to aid Natural England in providing advice to developers and regulatory authorities on potential compensation measures for benthic habitats; noting that specific measures would need to be developed on a case-by-case basis.
A list of 13 Annex I, Broad-Scale Habitat (BSH) and Features of Conservation Interest (FOCI) protected habitats identified as being at greatest risk of adverse effect as a result of future OWF development was provided by Natural England. From this, a further 38 habitats were identified as having the potential to provide similar or identical ecosystem service provision to the original 13 key habitats. Following an evidence review, scores for a range of ecosystem services and sensitivities were determined for each of the 51 habitats. Benthic habitat clusters were identified through multivariate analysis of the assigned ecosystem service scores.
A total of 16 benthic habitat clusters were determined, comprising habitats of similar or identical ecological function and ecosystem service provision. Broad and fine scale spatial habitat data were considered, including datasets relating to Annex I ‘Sandbanks’ and ‘Reef’, BSH (EUNIS Level 3) habitats and FOCI. The spatial extent of each habitat cluster within English waters was determined based on a wide range of publicly available datasets. Confidence was also assessed based on the number of datasets representing a given cluster present within any one area, combined with the specificity of the component datasets themselves. A series of interactive maps were produced that demonstrate both a habitat cluster’s spatial extent, and its potential confidence within a given area to provide same feature compensation.
Following review of the spatial output, findings indicate that whilst some habitats have a wider range of similar habitats available in English waters for compensatory measures should they be required, others have only limited equivalent, or close equivalent substitutes. Results highlight habitats with limited equivalent ecosystem service habitat availability, those that currently have limited spatial data availability, and those limited in both respects.
This evidence review and spatial assessment was undertaken at both a high-level and across a broad geographical scale. It was intended that this would provide Natural England with a baseline approach for identifying and assessing potential same feature compensation in English waters, for use as compensatory measures. Throughout this document, a number of constraints are identified, and recommendations made for the refinement of this present method as part of a case-by-case basis assessment. The results from this study has at this preliminary stage, indicated those potential regions to be explored should habitat compensation be required through the consenting of future OFW developments.