A biodiversity net gain assessment relates the habitat baseline to the proposed development and the applicable statutory requirements in England. We prepare the habitat evidence and metric work while keeping BNG aligned with the wider ecological design.
Biodiversity Net Gain Assessment
Habitat baseline, statutory metric and delivery requirements considered with the development design and wider ecology.
Biodiversity Net Gain Assessment enquiry
The habitat baseline
Existing habitat type, extent and condition provide the starting information for the applicable biodiversity metric.
Proposed habitat changes
The assessment compares the development's habitat losses and gains using the relevant metric rules.
Habitat baseline and proposed losses
Habitat type, extent and condition provide the baseline for the metric. The current layout then determines which habitats are retained, lost, created or enhanced, so design changes can alter the calculation.
For development subject to statutory BNG in England, the current metric and biodiversity gain plan process apply. Eligibility, exemptions and transitional rules depend on the application and should be checked against the live guidance rather than inferred from site size alone.
Discuss biodiversity net gain assessment
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Delivering biodiversity gains
Proposed habitat creation or enhancement needs a deliverable location, management and long-term responsibility. Off-site gains and significant on-site habitat enhancements relied on for statutory BNG must be secured and maintained for at least 30 years. Other on-site changes are not automatically subject to that same requirement.
BNG does not replace protected-species duties and should not be used to justify avoidable impacts on important habitats. The metric and the wider ecological assessment need to respond to the same design.
Biodiversity units and long-term management
The statutory metric treats area habitat, hedgerow and watercourse units separately and applies trading rules to losses and gains. Current England guidance also contains exemptions and specific rules for non-major development, so the applicable hierarchy and delivery requirements are checked for the application rather than repeated as a universal checklist.
Biodiversity Net Gain Assessment: common questions
Does BNG replace protected-species surveys?
No. Habitat gain requirements and protected-species obligations need separate consideration.
Can the metric be completed without reliable habitat information?
The calculation needs an appropriate and current baseline. Unverified assumptions can undermine the result.
Can a layout change affect the gain calculation?
Yes. Changes to retained, lost or proposed habitat can require recalculation and a revised delivery plan.
Can extra grassland units offset a hedgerow shortfall?
Not directly. The metric treats different unit types separately and includes trading requirements that the proposal must meet.