This policy briefing, published on the 4 September 2025, analyses the likely impacts of England’s mandatory nature-offset markets – Biodiversity Net Gain and Nutrient Neutrality.
It finds that the current approach to valuing and monitoring habitats created under the biodiversity net gain framework risks delivering habitats that are smaller, less diverse and in worse ecological condition than the habitats that have been destroyed for development. Whether this risk is borne out in practice should be a focus of future evaluation.
Key recommendations include:
- Prioritise Local Nature Recovery Strategies (LNRS): Give greater weight to LNRS in the statutory biodiversity metric to improve habitat valuation and restoration outcomes.
- Monitor habitat outcomes: Track whether current biodiversity metrics result in reductions in habitat size, variety, or declines in ‘at risk’ species.
- Refine habitat valuation: Adjust universal difficulty multipliers to better account for context, connectivity, and species-level diversity.
- Develop robust registries: Ensure transparency and accountability in nature offsetting markets, agri-environment schemes, and other conservation funding mechanisms.
- Increase Local Planning Authority ecological expertise: Strengthen the capacity of local planning authorities to approve, monitor, and manage Biodiversity Net Gain commitments effectively.
The briefing recommends that the approach to habitat valuation increases the incentive to create habitats that are aligned with the Lawton principles and contribute to Local Nature Recovery Strategies.
The Review Group members included Professor David Baulcombe FRS, Sir Ian Boyd FRS, Dr Sophus zu Ermgassen, Professor Yadvinder Malhi CBE FRS, Professor Pete Smith FRS, and Dr Jonathan Wentworth.