Biodiversity Net Gain, guidance for developers and ecological consultants

What is required for validation?

• Biodiversity Net Gain Assessment and Report.
• A fully completed DEFRA Biodiversity Metric Calculation Tool (in Excel format). The statutory version of the tool must be used for the assessment.

Further information and guidance - minimum requirements for determination

A Biodiversity Net Gain Assessment must be provided outlining how the Biodiversity Gain Objective will be met. This must be prepared by a professional ecologist with suitable qualifications and experience and be in accordance with the British Standard BS8683 'Process for designing and implementing biodiversity net gain - specification' (opens new window). Biodiversity net gain must always follow the principles outlined in 'Biodiversity Net Gain - Good Practice Principles for Development'.

The assessment should include details of:

• Information required through Paragraph reference ID 74-009-2023 of the [Draft] Biodiversity Net Gain Planning Practice Guidance (opens new window);
• The proposed methods of delivery of the biodiversity gain objective including onsite gains, off-site gains and the use of statutory biodiversity credits; 
• How the biodiversity gain hierarchy has been considered and adhered to;
• Information about any potential planning obligations required to deliver the biodiversity gain objective connected to the planning application (for example: should a S106 agreement be required to secure significant areas of onsite habitat).

A draft version of the Statutory Biodiversity Metric Calculation Tool (in Excel format) must be submitted. This should be completed in accordance with the Biodiversity Metric Principles included in 'The Statutory Biodiversity Metric User Guide (opens new window)' published by DEFRA. As a minimum this should include completed sections for onsite pre-and post-development habitat delivery.

The following supporting information must be submitted alongside the metric:

• Completed statutory biodiversity metric condition assessments for baseline habitats, including supporting information i.e. species lists and quadrant locations;
• Predicted habitat condition assessments of created/enhanced post-development habitats and details of the realistic and appropriate interventions/management regimes which are being suggested to achieve the stated condition/s and secure the biodiversity enhancements for a minimum 30 years post enhancement/creation;
• Pre- and post- development site plans clearly showing polygons and areas for each habitat used to populate the statutory metric calculation tool using UK Habitat Classification symbology (shape files in GIS or AutoCAD may be requested). The plans must be drawn to an identified scale and show the direction of north. Plans using Phase 1 symbology are not acceptable.
• Polygons within pre- and post- development plans should be labelled with a Habitat Reference Number which should also be noted within the associated column within the Statutory Metric Tool.

Where it is suspected the baseline value of a site has been affected negatively prior to assessment the LPA may require an assessment of the site based on its condition before such an occurrence. This may need to be based on aerial photos and/or historic information held by the Council and if there is any doubt regarding the Distinctiveness or Condition of habitats/features it will be assumed that the highest likely value will apply.