Biodiversity metric
A biodiversity metric is a rules-based calculation method that converts selected habitat characteristics into standardized biodiversity units or scores. Depending on the method, inputs can include habitat type, area, condition, strategic significance, location, difficulty, and the time required to create or restore habitat.
In simple terms
Metrics simplify selected ecological information so plans or outcomes can be compared consistently under one method. England's statutory metric calculates baseline and post-development habitat units for applicable Biodiversity net gain decisions, with separate calculations for habitat categories and adjustments for delivery risk. A biodiversity metric is not a complete inventory of Biodiversity: it reflects the variables, condition assessments, spatial rules, multipliers, and exclusions chosen by its methodology. Results from different metrics are therefore not automatically comparable.
Why it matters
A shared method can make habitat losses and proposed gains visible, support consistent planning decisions, and discourage vague claims. Yet a single score can hide irreplaceable habitat, species needs, connectivity, or uncertainty. Decision-makers should read the calculation alongside ecological evidence and the mitigation hierarchy, not treat units as proof that every impact on an Ecosystem is interchangeable.
Example
A developer maps habitats before work, records each area's type, size, condition, and strategic significance, then models retained, enhanced, and newly created habitat with the statutory tool. The calculation indicates whether the plan reaches its required Biodiversity net gain, while field surveys and the biodiversity-gain plan address evidence the score alone cannot capture.
References
Current status
- As of
- Issuer
- Department for Environment, Food & Rural Affairs
- Jurisdiction
- England
- Instrument or version
- Current statutory biodiversity metric and calculation tools
- Status
- The statutory biodiversity metric is the prescribed biodiversity-gain calculation method for applicable development in England.
Applicability: Use the current tool and guidance for the relevant planning route. Exemptions, small-site treatment, habitat rules, competent-person requirements, and commencement dates can change; a metric result does not replace the full biodiversity-gain plan or other planning duties.