Information about biodiversity net gain for ecologists
This page has been created to provide additional information to Ecologists undertaking Biodiversity Net Gain Assessments within Kings Lynn and West Norfolk.
Planning Applications
To validate a planning application, the following documents must be submitted:
- Statutory Metric
- Statutory Metric Condition Assessments
- Baseline Habitat Map
Where an application is classed as a Major, and/or has a high baseline ecological value, a draft HMMP and post development values may be required during determination to understand how 10% will be delivered. Any grant of consent for an application subject to the General Biodiversity Net Gain condition will include a condition on the decision notice that requires the Biodiversity Gain Plan (BGP) to be submitted prior to commencement. Any application delivering onsite significant net gain and/or net gain within a blue line boundary will also be assigned a condition requiring submission of a Habitat Mitigation and Monitoring Plan (HMMP).
Supplementary Biodiversity Gain Assessment Reports are welcome and should outline which method of delivery will be relied on to deliver 10% net gain. Where not clear or where this information is not provided the applicant will be asked to confirm which delivery method, they intent to rely on (onsite/offsite/Habitat Bank Units) in order to inform which planning obligations the LPA must use to secure the 10%. This can be in the form of a simple email or may be included in any supplementary reports.
Discharging of condition applications
To discharge the General Biodiversity Net Gain condition, an application must be submitted with:
- The Statutory Metric (with no red boxes showing)
- The Biodiversity Gain Plan
- Baseline and post development Habitat Maps
- Habitat Mitigation and Monitoring Plan (where also conditioned)
Government Templates for BGP and HMMP should be used.
A Habitat Mitigation and Monitoring Plan cannot be discharged without the Biodiversity Net Gain Plan being approved and visa versa. This is because the LPA must be sure of how the BNG will be delivered over 30 years and the Habitat Mitigation and Monitoring Plan must be in accordance with the approved Biodiversity Net Gain Plan.
Where Units have been purchased this is slightly different. The following would need to be submitted:
- The final Metric (with no red boxes showing - the Unit provider usually completes the offsite tabs and will need to update the front page of the Metric)
- The Biodiversity Gain Plan
- Proof of Purchase of Units
The Habitat Bank reference number of the provider you have used must be included in your Biodiversity Net Gain Plan. The Habitat Bank must show as registered on the Natural England offsite register at validation. To discharge the condition, the Units must be shown as allocated to your development on that register. Where offsite blue land is used, this must be shown as registered and allocated in the same way.
To find local Habitat Banks please view our information for developers page.
General
The following general points should be given consideration when undertaking Biodiversity Net Gain assessments:
- Damage to irreplaceable habitats must be avoided. Where damage to irreplaceable habitats cannot avoided early discussions must be had with the local planning authority.
- Species enhancements should not be overlooked but should be incorporated in tandem with Biodiversity Net Gain to maximise benefits and opportunities of the development. This should include integrated bird, bat or insect box provision, hedgehog-friendly fencing.
- Condition assessments must be provided and comments included within the Biodiversity Metric to justify habitat type, condition, or strategic significance allocation. Provision of further information within the comments section of any part of the Metric is welcomed and encouraged.
- Strategic Significance for each habitat type must be fully justified within the comment’s column of the Biodiversity Metric and align with the Norfolk LNRS.
- All Biodiversity Net Gain documents must be consistent with all final versions of project documents that are submitted in support of an application. Any changes to the masterplan must be reflected in the final Metric calculation.
- Software used to measure areas and length included within the Metric should be identified. Measurements should be made using GIS or similar software and follow Natural England guidance to ensure accuracy where possible.
- Where templates are available from DEFRA / CIEEM / Natural England for HMMP and Net Gain Plans these must be used when submitting documents in support of an application. This will aid the review process and avoid delays.
- Where habitats are created inside of residential gardens this is likely to be classified as vegetated garden or un vegetated rather than individual habitat types. This includes any hedgerows, trees, grassland and shrubs within the garden. Any deviation from this must be fully justified within the comments section of the Metric.
- The size of created trees correlates with the DBH of a tree at the time of planting. Trees created post development are likely to be small. Medium sized trees are not commonly found in standard plant nurseries and are difficult to move and plant. Anything larger than small will therefor need to be fully justified. Appropriate evidence of competency to undertake Biodiversity Net Gain calculation and design mitigation, management and monitoring schemes must be provided. This will include, but is not limited to, experience with Biodiversity Net Gain schemes and Metric calculations, relevant professional membership and botanical qualifications (FISC).
- Where watercourses are present within the baseline, evidence of Modular River Survey Training (MoRPh) must be provided with the submission of the Metric. This does not include ditches.
Local Nature Recovery Strategy
The Norfolk Local Nature Recovery Strategy (LNRS) was published on 31 October 2025. The LNRS and mapping tool can be found on the Norfolk County Council website.
The LNRS is now a material planning consideration. This will primarily affect the post development values of any future planning applications or those currently under consideration. This will not affect the baseline of any applications which already have consent but where applications are currently being determined all baseline habitats should be recorded in accordance with the Metric User guidance (i.e. Low).
Page 27 of the Statutory Metric User Guidance includes a link to more detailed advice hosted by the Planning Advisory Service.