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Defining Irreplaceable Marine Habitats (NECR474)

Understanding which habitats should be considered irreplaceable in the marine environment is important for Natural England’s marine casework and evolving policy. Knowing which habitats are irreplaceable will assist developers, planners and regulators to avoid habitats that cannot be replaced or recreated elsewhere in compensation for their loss.

The Marine Biological Association of the UK (MBA) was commissioned by Natural England to define marine habitat irreplaceability and coastal and marine irreplaceable habitats. The commissioned project consisted of three stages:
Stage 1: A literature review on definitions of marine habitat irreplaceability. nno specific definition of marine habitat irreplaceability was sourced that had been previously developed and applied.

Stage 2: Interviews with experts to further discuss and refine criteria for marine habitat irreplaceability. Key discussion points focussed on: i) criteria that should be included or excluded, ii) terminology and iii) applicability of a national generic definition of marine habitat irreplaceability based on the UK Marine Habitat Classification versus regional and local assessments. Following the interviews, the definition of irreplaceable marine habitats was refined.

Stage 3: A systematic assessment of the irreplaceability of marine and coastal habitats was undertaken based on: natural recovery potential (years to recover), rarity (based on number of records and regional distribution), and the environmental context (physical habitat, hydrodynamics) and rarity/distinctiveness of the biological assemblage. Categories were created to assess each criterion with weighted scores assigned to each category. Scores were summed to provide an overall score for irreplaceability for each habitat.

No threshold for scoring was identified at which a habitat is considered irreplaceable. Any habitat that scored highly for any of the assessed criteria may pose challenges for recovery, restoration or recreation. However, habitats that score above 40 were may be a combination of slow recovering, unfeasible to recreate, rare or unique. An assessment showed that most habitats that score highly against irreplaceability criteria are recognised through Marine Protected Area (MPA) designations, conservation targets and lists of conservation interest habitats and features.

The project outputs include this technical report and a workbook (Excel spreadsheet), which provides an audit trail of the evidence and decisions made and summary scores.

Downloads available for this record

File Uploaded
NECR474 Edition 1 Defining Marine Irreplaceable Habitats, PDF, 1.4 MB 2023/02/24
NECR474_Workbook_Defining Marine Irreplaceable Habitats, XLSX, 672.3 kB 2023/02/23

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