Biodiversity Net Gain

Glossary

Biodiversity Net Gain (BNG): A mandatory approach requiring developments to enhance biodiversity by at least 10% compared to the pre-development baseline.

Environment Act 2021 – The UK legislation that made BNG a mandatory requirement for most developments in England.

UKHab: The UK Habitat Classification system used to assess existing and proposed habitats on a site.

Defra Biodiversity Metric: A tool used (Excel spreadsheet) to measure habitat quality and value pre- and post-development to calculate net biodiversity gain or loss.

Mitigation Hierarchy: A planning principle requiring developers to avoid harm to biodiversity first, then minimise it, and finally compensate for residual impacts.

Habitat Bank: A registered area of land managed to generate biodiversity units that can be sold to developers who need to offset biodiversity loss elsewhere.

BNG Units: Quantified measures of biodiversity created or lost, as calculated using the Defra metric.

Natural England: The statutory body responsible for the BNG metric, guidance, and accreditation of biodiversity gain sites.

Planning Authority: The local authority responsible for assessing and approving BNG plans submitted as part of planning applications.

Statutory Credits: Biodiversity compensation credits sold by the UK government when BNG cannot be delivered through on-site or off-site units.

Spatial Risk Multiplier: A factor applied in the BNG metric that increases unit requirements if offsetting is delivered far from the impact site.

Irreplaceable Habitat: Natural areas like ancient woodland or veteran trees that cannot be recreated and are exempt from the BNG requirement.

Section 106 (s106) Agreement: A legal planning obligation used to secure long-term delivery of biodiversity outcomes post-development.

Responsible Body

Conservation Covenant

National Planning Policy Framework (NPPF) : The overarching policy document that embeds biodiversity enhancement within planning decisions.

Local Nature Recovery Strategy (LNRS): A spatial strategy identifying priorities and opportunities for nature recovery in each local area.

Biodiversity Gain Plan (BGP): A mandatory document that demonstrates how a development will meet the minimum 10% biodiversity gain requirement.

Habitat Management and Monitoring Plan (HMMP): A document detailing how habitats will be created, managed, and monitored over at least 30 years.

Baseline Survey: An ecological survey identifying and classifying habitats on a site prior to development using UKHab methodology.

Monitoring Report: A periodic report submitted to the planning authority or responsible body to demonstrate delivery and ongoing compliance.

Time-to-Target Risk Multiplier – A risk factor applied when habitat creation takes years to reach its target condition.

Difficulty-of-Creation Risk Multiplier – A metric adjustment accounting for uncertainty in successfully creating certain habitat types.

Trading Rules – Rules within the Defra Metric preventing replacement of high-distinctiveness habitats with lower-distinctiveness ones.

Habitat Distinctiveness – A measure of how rare or important a habitat type is in biodiversity terms.

Habitat Condition – A qualitative assessment of how well a habitat functions to support biodiversity.

Connectivity – The degree to which habitats are linked, enabling wildlife movement and ecological function.

Strategic Significance – A multiplier rewarding habitat creation in priority locations identified in strategies such as LNRS.

Off-Site Units – Biodiversity units delivered on land outside the development site to achieve BNG targets.

Biodiversity Gain Site Register – The national register maintained by Natural England, listing land legally secured for BNG delivery.

Biodiversity Units Market – The emerging marketplace allowing developers to purchase off-site biodiversity units to meet their obligations.

Private Market Credits – Units generated by private landowners or habitat banks, as distinct from statutory credits sold by government.

Additionality – The principle that biodiversity gains must be above and beyond what would have occurred without the intervention.

Permanence – The requirement that biodiversity enhancements must be secured and maintained for a minimum of 30 years.

Monitoring and Adaptive Management – The process of checking habitat performance and adjusting management to achieve intended outcomes.

Stacking and Bundling – Terms used where multiple environmental markets (e.g., carbon, nutrient neutrality, BNG) apply to the same land parcel.