What is biodiversity net gain?

Biodiversity net gain is a new requirement to deliver biodiversity enhancements linked to development proposals. It was introduced in legislation – the Environment Act 2021 - to counter the loss of wildlife habitats across England and provide increased amounts of biodiversity.

For qualifying development proposals from 12 February 2024 onwards it is unlawful to issue a planning approval for any scheme that does not secure 10% biodiversity net gain, with 30-year management and monitoring.

How is biodiversity net gain assessed?

It will apply to development proposals of a specified type and scale. Where proposals meet these criteria, applications for planning permission will need to show the level of biodiversity habitat at the date of planning submission and how the scheme will provide the 10% uplift.

The requirement to provide for biodiversity net gain (or not if exempt) does not exclude the need to protect existing nature conservation habitats or enhance these under separate local or national planning policies.

Qualifying sites

Not all development proposals requiring planning permission have to provide for biodiversity net gain. The following schemes however do:

Large sites/major development

• erection of 10 or more dwellings or housing development on a site 0.5 hectare or more

• erection of a building or buildings where the floor space to be created is 1,000 m2 or more

• development on a site 1 hectare or more

• minerals and waste development

Small Sites/Minor development

Residential developments with 1-9 dwellings on a site measuring less than one hectare

Non-residential sites with floor space created less than 1,000 square meters or site area less than one hectare

Sites/development proposals that are exempt from meeting BNG requirements:-

These include: Text to be updated as the Government have changed the Guidance as of Dec 2024

• biodiversity net gain sites, developments undertaken for the purpose of fulfilling the biodiversity net gain planning condition for another development

• householder applications

• self-build and custom build application for fewer than 10 houses on a site no larger than 0.5 hectare

• HS2 applications, Crown development, Development Consent Orders

• temporary use of which any habitat lost will be fully reinstated within two years of impact

Statutory biodiversity metric

Biodiversity net gain is calculated using a statutory biodiversity metric. It measures the biodiversity value of habitats to assign a numerical value, measured in 'biodiversity units'.

The metric is used to calculate how a development might change the biodiversity value of a site. It can help developers design, plan and make land management decisions that better support biodiversity. The metric considers:

• habitat size

• habitat quality

• habitat location

• habitat type

Details of the statutory biodiversity metric can be downloaded from the Gov.UK website.

Competant person

When using the metric to determine the biodiversity net gain position on an application, this should be undertaken by a competent person. Competent person is defined in the statutory metric guidance. This should be an Ecologist or Landscape Architect.

For developments in Staffordshire the LA will consult Staffordshire Wildlife Trust to verify the informaiton submitted and commnet on compliance with legislation and guidance.

The LA would prefer net gain to be achieved on site. Some developments where it would be impossible to achieve net gain on site would be allowed to buy credits via a s106 agreement for provision off site.

Small Sites Metric

Published Nov 2023

For small sites the SSM tool can be used. The calculation can be carried out by an Architect, Landscape Architect or Ecologist.

The tool can be used for:-

• residential development where the number of dwellings is between 1 and 9 on a site of an area 1 hectare or less, or if the number of dwellings is unknown, the site area is less than 0.5 hectares
• commercial development where floor space created is less than 1,000 square metres or total site area is less than 1 hectare
• development that is not the winning and working of minerals or the use of land for mineral-working deposits
• development that is not waste developments

The SSM tool cannot be used where:

• There are Prority Habitats within 500m of the site
• sites containing riparian zones
• where no statutory protected sites or habitats are present
• where no European protected species are present
• Ancient or veteran trees are prresent

Where statutory protected sites or habitats are located within 500m of the development site boundary. We need to considere whether an ecologist should be contacted and the SBMCT tool used.

Losses /Trading Rules

Med: nust be replaced by an area of babitat units within the same borad habitat type

Low: Losses must be replaced with an area of habitat units of the same or higher band

Very low: Area Trading rules do not apply. For hedgerwo these must be replaced with the same or higher band .

Supporting Information

Supporting infirmation must be submitted with teh Tool calculation spreadsheet in the form of:-

• A site plan as exisitng shwoing areas calculated
• A site plan as proposed showing areas calculated
• Record photographs - up to 40
• Description of the habitats
• The areas must add up to the site area, so you will need to enter values for Built Form and Fencing and Walling as well as other haitats
• If net gain cannot be delivered on site, it can be delivered off site as part of a S106 agreement