The project evaluated five key research questions developed by the ORJIP steering group:

• RQ1: Are there suitable metrics to detect changes in benthic habitats for offshore wind assessments?
• RQ2: Is there measurable change in biodiversity and/or species composition?
• RQ3: Are there localised and regional ecological effects around infrastructure?
• RQ4: Is there change in ecological function as a result of biological changes?
• RQ5: Can recovery and/or enhancement be demonstrated and in what timeframe?

The project was delivered across five work packages: a literature review; collation of benthic monitoring datasets; an interim workshop with the steering group to identify which research questions should be investigated further through benthic data analysis and which analytical approaches should be prioritised; analyses using AMBI (AZTI Marine Biotic Index) and biological traits analysis; and final reporting.

The literature review found that existing metrics (e.g. diversity indices) are suitable for detecting changes (RQ1), though other approaches such as AMBI and biological traits analysis could offer additional ecological insight that compliments traditional approaches. Evidence of biodiversity and species changes (RQ2) was noted in OWF monitoring reports but attributed mainly to natural variability, contrary to scientific literature which attributed benthic habitat changes to the construction and presence of offshore wind farms. Localised effects near turbines were documented (RQ3), but regional-scale impacts remain poorly understood. Functional ecological changes (RQ4) are rarely assessed and poorly understood, and recovery timelines and enhancement (RQ5) vary by habitat, with more long-term monitoring required.

Further analysis using AMBI and biological traits analysis found no significant spatial differences between array areas and reference stations, supporting conclusions that natural variability was the primary driver of benthic habitat change at the analysed sites. Limitations of these analyses were highlighted however, it was considered that these metrics offer potential to characterise ecological responses and ecosystem functioning, complementing traditional analyses.

The project's findings informed several policy considerations, including improving environmental impact assessment processes, supporting licensing standards, informing compensation strategies, and contributing to marine net gain approaches. Key recommendations included further research; development of monitoring approaches incorporating functional ecology, longer-term studies, standardised monitoring protocols with adequate statistical power, and consideration of cumulative regional effects across multiple offshore wind farms.