Biodiversity Net Gain now mandatory: What developers need to know

Biodiversity Net Gain (BNG) refers to the policy and practice of ensuring that development projects have a positive impact on biodiversity, meaning they leave the natural environment in a better state than before.

From 12^th February, it became mandatory under the Environment Act for developments to deliver a BNG of at least 10%, but the reality is that many local authorities are requiring significantly more than this.

Now that the requirements are starting to be embedded, what do developers need to know and what are our top tips to ensure BNG compliance? David Ramsay, Head of Planning at Vail Williams, explores.

Do your homework

Before acquiring development land, it is important to undertake pre-acquisition due diligence to establish what the requirements of the local authority in question are, so that you can undertake a viability assessment in line with this.

Bear in mind that some authorities already require in excess of 10% biodiversity net gain. For example, Guildford Borough Council requires at least 20% BNG.

Utilise biodiversity metrics and tools to measure and evaluate the biodiversity value of a site.

This may include tools like the Biodiversity Metric 4.1, which helps quantify the biodiversity units for different habitat types.

Get a site assessment

The best way to undertake an early assessment of the baseline biodiversity rates onsite, is with a professional ecologist, so that you and your planning partners will know early on what level of BNG you will need to deliver.

The will identify existing habitats, species, and ecological features and use this information to inform the development plan, designing effective mitigation and biodiversity enhancement measures.

From there, you can work out what types of habitat will get you to that requirement without undermining the commercial viability of your scheme.

There will be certain types of habitat that can deliver more BNG than others, such as trees and woodland, for example. All of which an ecologist can advise you on.

Understand the mitigation hierarchy

Follow the mitigation hierarchy, which typically involves avoiding impacts where possible, minimising unavoidable impacts, restoring or enhancing affected ecosystems, and only as a last resort, offsetting any remaining biodiversity losses.

If it becomes clear that it won’t be possible to deliver BNG onsite, there are a range of mitigation options, which are in their infancy, and will need to be agreed alongside the local planning authority. This can involve a commitment to plant offsite or obtaining credits for planting off-site, for example.

Stakeholder Engagement, Long-Term Monitoring and Management

Engage with local communities, environmental organisations, and other stakeholders to ensure that their perspectives and concerns regarding biodiversity are considered in the development and planning stages.

Think about developing and implementing a long-term biodiversity monitoring and management plan. This involves ongoing efforts to ensure that the intended biodiversity gains are achieved and maintained over the life of the development.

Integrate BNG with your wider sustainability goals

Integrate biodiversity net gain requirements with other sustainability goals. Consider how the development aligns with broader environmental, social, and economic sustainability objectives.

Document and evaluate progress

Keep detailed records of biodiversity assessments, mitigation measures, and outcomes. Be prepared to report on biodiversity net gain achievements as required by regulatory or local authorities.

Non-compliance with biodiversity net gain requirements could result in penalties, delays in project approval, or even the rejection of planning permission, so developers need to demonstrate how they will achieve the required BNG for their proposed development, if it is to achieve planning permission.

Not only this, as a relatively new additional requirement, many local councils aren’t yet upskilled or resourced enough to process BNG, which has the potential to add further delays to the planning determination process whilst they get up to speed.

The best thing you can do to ensure the success of your proposed development, is to seek biodiversity net gain advice early on from ecologist and planning professionals, who will work with you to ensure that your develop remains commercially viable.

For more information on the BNG requirements in a specific local authority boundary, or for help and advice on mitigation measures, our planning team can help.