Biodiversity Net Gain
Biodiversity Net Gain (BNG) is an approach to development and land management that aims to leave nature in a measurably better state than beforehand. It became a mandatory requirement for major developments across England in February 2024 under Schedule 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021). The purpose of this is to ensure that new developments contribute positively to nature’s recovery by aiming to create ‘additional’ (or ‘net gain’) biodiversity on a site, essentially leaving nature in a better state post-development.
Biodiversity Net Gain is important because:
The natural environment provides benefits to us all, and is essential for the processes that support life on this planet, also known as Ecosystem Services.
Many habitats are lost or degraded by development, and there are limited measures in place to value, maintain, enhance and create wildlife habitats.
It delivers measurable improvements for biodiversity by enhancing or creating new habitats in association with development.
What is involved with Biodiversity Net Gain?
Biodiversity Net Gain encourages developers to consider site selection based on the existing ecological value of a site and to integrate this into the development layout, retaining habitats for wildlife while also maintaining the ecosystem services they provide for people. Opportunities to enhance biodiversity should be discussed during the designing, constructing, operating, and maintenance stages of a development. It demands thoughtful design, stakeholder inclusion and collaboration with ecology experts to minimise biodiversity loss from the outset, which can also reduce development costs.
Overall, there is no objective ‘best’ way to achieve BNG; it will look different across different developments. It’s about finding the best solution based on the existing habitats and local landscape context, considering regional and national nature priorities to bring about long-term, meaningful benefits.
Who does it apply to?
All sizes of development, whether a single home to a large-scale project such as housing estates.
Building, infrastructure, and sites used by developers, such as construction compounds.
Developments requiring consents such as planning permission, and those not requiring consent such as projects under permitted development rights.
Developments that are new, underway or routine maintenance activities.
Who is exempt?
Development sites below the threshold, which means anything less than 25m2 of habitat, or less than 5m of liner habitat, such as a hedgerow.
Householder applications, such as home extensions, conservatories, or loft conversions.
Self-build/custom-build applications.
Anything forming part of the high-speed railway transport network (HS2).
Ask Pioneer about providing BNG exemption letters for your development application.
How is Biodiversity Net Gain Achieved?
Biodiversity Net Gain requires developments to demonstrate a 10% net gain on the existing biodiversity of a Site. To enable this, BNG places a standardised numerical value (or unit) onto habitats allowing gains or losses to be measurable. This approach helps justify ecological design or mitigation and reassures developers of a practical service.
A baseline habitat survey is required for Pioneer to determine the types of habitats present at the site, assessing their condition against a standardised criterion. A BNG calculator - The Statutory Biodiversity Metric Tool - is then used which takes the habitat data and allocates biodiversity units to calculate the baseline biodiversity value of the site. The output will break the site up into habitat, hedgerow and watercourse units which are each calculated separately. Note that this calculator does not factor non-habitat features such as species presence or artificial wildlife boxes.
The baseline biodiversity result can then be used to aid the design stage of a project by indicating any high-value habitats that should be retained, lower value habitats which could be enhanced, or which habitat-type could be created on-site to benefit biodiversity. By avoiding or minimizing losses to sensitive habitats and incorporating intelligent design early on, Pioneer can help to achieve a 10% net gain at minimal cost, saving your development money.
The Mitigation Hierarchy
Any development must demonstrate that it has applied the mitigation hierarchy through thoughtful design that prioritises habitat retention above all else where possible.
Avoid habitat loss by prioritising retention
Minimise loss through design considerations
Restore (or enhance) any degraded habitats post-development
Compensate for lost habitat through re-creation elsewhere
on-site or through off-site options
In cases where it is absolutely not possible to achieve a net gain within the development site, there are two further provisions to meet the mandatory 10% requirement. These involve utilising ‘off-site’ BNG which includes any land that falls outside the development or red-line boundary.
‘Off-site’ Units – This involves using additional land which is considered ‘off-site’ from the development to meet BNG through further habitat creation/enhancements. This land must fall within the same ownership as the development, and any additional units created will go towards the final net gain result. Pioneer can survey and help identify potential ‘off-site’ areas to ensure it meets the BNG requirements.
If a developer has no suitable land for this, then off-site biodiversity units equating to the amount required can be purchased on the BNG market from a local habitat bank. The habitat bank then uses the funds for a range of habitat management or restoration schemes, ensuring biodiversity is still benefitted.
If the development can still not meet the biodiversity unit requirement, and have evidenced that there is no alternative, then Statutory Biodiversity Credits must be bought from the government to be invested into national biodiversity projects.
Utilising these options are viewed as a last resort and developments should exhaust all possibilities to achieve a net-gain on-site first, as outlined in the BNG mitigation hierarchy.
Biodiversity Net Gain Assessment
A development must be able to demonstrate that they can achieve a net gain by outlining the specific habitat enhancement or creation they will carry out. It is therefore essential that a biodiversity net gain is planned early in the development.
A BNG report produced by Pioneer Environment will include:
An assessment, taking every aspect of the project into account at the project feasibility stage, as to whether the project can deliver BNG or not.
Concise, easy to follow advice for the project to maximise its ability to deliver BNG, considering factors such as location, design, construction methods and programme.
Consideration of the potential for on-site or off-site delivery of BNG. This can include securing land in close proximity to the project site, more distant land under direct control, a brokered agreement or through the purchase of statutory biodiversity credits.
Where the delivery of project-wide BNG is not considered possible (e.g., as a result of impacts to irreplaceable habitats or other site constraints), Pioneer will provide a record of the reasons and a clear commitment to delivering biodiversity gains elsewhere through the project.