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Biodiversity Net Gain and ecology

Biodiversity Net Gain (BNG) is an approach to development, that aims to leave the natural environment in a measurably better state than beforehand. This means protecting and enhancing important existing habitats and ensuring that environmental features which are lost or degraded are compensated for by restoring or creating new habitats; it is a necessary approach to help enable the recovery of nature across England

We have been requiring a minimum of 10% biodiversity net gain as a requirement of planning permission for 'major' new build development net gain from development for some years now, but new legislation has now come into force that makes it a statutory obligation.

On 12 February 2024, mandatory biodiversity net gain commenced for major development under Schedule 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021).

Small site development includes residential development where the number of dwellings is between 1 and 9, or if unknown the site area is less than 0.5 hectares, and commercial development where floor space created is less than 1,000 square metres or the total site area is less than 1 hectare. For small sites, mandatory BNG will commence from 2 April 2024.

For small sites, the council's interim advice note still applies until the mandatory requirement commences on 2 April 2024.

Ecology and Biodiversity Net Gain – Interim Advice and Information Note (PDF) [1MB]


Biodiversity Duty Report

We have published a report to identify the work we do that contributes towards the conservation and enhancement of biodiversity. The report highlights the main areas of NFDC's work that help us to deliver the 'biodiversity duty'.  You can read below or download a copy

Biodiversity Duty Status Summary (PDF) [1MB]


Ecology surveys for planning applications

Before you seek planning permission for many potential new land developments or building work at a residential property, for example an extension or rebuild, various site surveys must be done.  This includes an ecological survey.  



There are some types of exempted development, and certain types of permission where the legal BNG requirement does not currently apply:

  • Permissions relating to applications made before the date of commencement for mandatory BNG i.e., 12 February 2024 (or for small sites, 2 April 2024) (however please note these will still be subject to the Council's requirement for BNG set out in local policy).
  • Section 73 permissions where the original permission which the Section 73 relates to was either granted before 12 February 2024 or the application for the original permission was made before 12 February 2024 (or for small sites, 2 April 2024).
  • 'De minimis' development that does not impact a priority habitat and impacts an area of non-priority onsite habitat less than 25m2, or 5m for linear habitats i.e., hedgerows and watercourses.
  • Householder applications as defined within article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015.
  • Self-build and custom-build development where these consist of no more than 9 dwellings, occur on a site area no larger than 0.5ha and it consists only of self build and custom housing as defined in section 1(A1) of the Self-build and Custom Housebuilding Act 2015.
  • Biodiversity gain sites - developments undertaken for the purpose of fulfilling the BNG planning condition for another development are exempt.
  • Permissions granted through a development order under section 59 (includes permitted development rights).
  • Urgent Crown development (granted under 293A of the Town and Country Planning Act 1990).

Other types of permission that are not subject to the BNG requirement include reserved matters approvals (these are not applications for permission, the BNG requirement is attached to the original outline permission), and permissions in principle (but the subsequent technical details consent would be subject to the general biodiversity gain condition).

Mandatory biodiversity net gain has not been commenced yet for planning permissions granted through other routes, including local development orders, neighbourhood development orders, successful enforcement appeals and deemed planning permission.

Please refer to the Defra blog for further information on exemptions and transitional arrangements.


What is required for mandatory BNG?

The approach to BNG delivery will need to meet various statutory minimum requirements as set out in the primary and secondary legislation, including the need to achieve a minimum 10% BNG and maintenance of these assets for at least 30 years. Every grant of planning permission will be subject to a pre-commencement condition that requires the approval of a Biodiversity Gain Plan before construction commences.

Developers should refer to draft planning practice guidance and Defra BNG statutory guidance for further detail on all statutory requirements.


What information do developers need to include with their planning application?

Applications should be supported by information to enable us to make a full consideration as to whether the general condition is capable of being successfully discharged. For developments subject to BNG, the Planning Practice Guidance stipulates a statutory minimum level of information, set out below:

  • a statement as to whether the applicant believes that planning permission, if granted, would be subject to the biodiversity gain condition
  • the pre-development biodiversity value of the onsite habitat on the date of application (or an earlier date) including the completed metric calculation tool used showing the calculations, the publication date and version of the biodiversity metric used to calculate that value
  • where the applicant wishes to use an earlier date, the proposed earlier date and the reasons for proposing that date
  • a statement confirming whether the biodiversity value of the onsite habitat is lower on the date of application (or an earlier date) because of the carrying on of activities ('degradation') in which case the value is to be taken as immediately before the carrying on of the activities, and if degradation has taken place supporting evidence of this
  • a description of any irreplaceable habitat (as set out in column 1 of the Schedule to the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations [2024]) on the land to which the application relates, that exists on the date of application, (or an earlier date)
  • a plan, drawn to an identified scale which must show the direction of North, showing onsite habitat existing on the date of application (or an earlier date), including any irreplaceable habitat

In line with Planning Practice Guidance, the council may request further information at validation stage where necessary to help assist the council in its assessment of BNG proposals in light of existing local policy requirements, and to provide confidence that the BNG objective can be satisfactorily discharged.

We encourage applicants to engage with our pre-application service to ensure any potential issues are identified, understood and resolved early on in the process, to reduce any future delay and improve the quality of a proposal.

Call for Projects - Biodiversity Net Gain and Nutrient Mitigation

New Forest District Council is inviting landowners and other interested parties to put forward proposals for projects within the district that will enhance local biodiversity and improve the condition of the River Avon and water quality in the Solent and Southampton Water.

Ecology and Biodiversity Net Gain Advice

From 7th July 2020 New Forest District Council has sought a minimum of 10% biodiversity net gain as a requirement of planning permission for 'major' new build development

Biodiversity Duty Status Summary

This report highlights the main areas of NFDC's work that help to deliver the 'biodiversity duty'.

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