What is Biodiversity Net Gain?

Biodiversity Net Gain (BNG) is defined by Baker (2016) in a CIRIA, CIEEM and IEMA 2019 publication as “development that leaves biodiversity in a better state than before” and an “approach where developers work with local governments, wildlife groups, landowners and other stakeholders to support their priorities for nature conservation”.

In practice, this means that all developments must have an overall positive impact on biodiversity. BNG is not intended as a barrier to development, but an integral part of the planning process.

Critically, it must go beyond mitigation, aiming to create extra habitat for wildlife, thus achieving a measurable net gain in biodiversity. Alongside this, it must also contribute to nature conservation and environmental priorities such as achieving net zero emissions by 2050.

It follows the government’s pledge to ‘leave the environment in a better state than we found it and pass on to the next generation a natural environment protected and enhanced for the future’, as set out in the 2018 DEFRA 25 Year Environment Plan.

BNG will transform how we plan, design, build and maintain developments. It has the potential to bring benefits to both people and wildlife such as giving our communities beautiful natural spaces and bringing back wildlife.

But it is also vital for reversing the effects of years of habitat destruction which have left our environment less resilient and natural resources depleted.

When should BNG be implemented?

With government assurances that the Environment Bill will pass into law by the end of this year, BNG will become mandatory for most developments in England.

It must be achieved for all developments except those that are of national significance (examples of this include large infrastructure projects such as the OxCam road network and HS2). These projects will, however, still have to undertake sufficient surveys and implement appropriate mitigation measures to comply with current legislation and guidance.

The Mitigation Hierarchy will be central to the BNG process. This hierarchy prioritises avoiding damage to habitat, then if that’s not an option, mitigation by reducing the impact where possible and, finally, if there is loss of habitat it must be compensated for.

It will be compulsory for developers to engage with and demonstrate to planning authorities that compensation options have been considered and evaluated.

In Wales and Scotland, BNG is not yet being put forward as a legal requirement. The Welsh government aims to publish its BNG strategy by 2023 as part of its Nature Recovery Action Plan. Scotland will consider how to secure positive benefits for biodiversity in its National Planning Framework 4 (NPF4) which is scheduled for September 2021.

BNG requirements

The Environment Bill, as well as mandating BNG, sets out specific requirements that need to be met to achieve it.

Any BNG measures implemented within the development site boundary will have to be registered by the developer. This will include showing how many conservation credits it is delivering.

These credits must incorporate a 10% increase in biodiversity for the site. The government will manage a national register where this data is recorded and available for review.

Applying BNG in practice

BNG must be considered from the outset of a project. When submitting the planning application for development, a biodiversity net gain plan must be included so it is critical to consider your BNG requirements as early in the development process as possible.

The first step is to carry out an assessment of the site of the proposed development and this is where APEM can help. Our highly experienced ecology team will work with you to identify how habitats may be impacted by a proposed development.

We create a baseline with existing data and undertake a site survey which is mapped using UK Habitat Classification methodology. For inaccessible or large-scale areas, we offer aerial surveys, such as H2OVER®.

H2OVER®’s ultra high-resolution imagery identifies habitat types and is used to model potential effects and options to inform the scope of any further survey requirements. It provides a baseline for habitat mapping which can be presented on a 3D visualisation, to aid communication and wider stakeholder engagement such as public consultations

In the field, data is then applied to the DEFRA Biodiversity Metric 2.0 which assesses the quality of the site based on habitat distinctiveness, condition, strategic significance and connectivity. The Metric 2.0 also takes into consideration rare or declining habitats and assesses the difficulty in restoring or creating new ones. This information is then translated into quantifiable biodiversity ‘units’ which are then used to inform the scope and nature of mitigation design.

On completion of the Metric 2.0 calculations, APEM’s knowledgeable team of ecologists and GIS specialists can further support your development through the BNG process to design habitat creation schemes.

We will make recommendations to ensure your BNG obligations are met and are aligned with the Mitigation Hierarchy. Our assessment will state the impact of the planned development and we will work with you to agree to pragmatic ways forward to achieve these obligations.

Our experience in habitat restoration projects and mitigation design ranges from rewilding rivers to building artificial badger setts and more. Our consultancy and field teams can enable you to deliver BNG projects in practice, ensuring that your development not only meets the statutory requirements, but also makes a measurable contribution to giving back to nature and our communities.

We have specialists located throughout the UK and Ireland, ensuring that we can support clients locally and quickly. If you have any questions or want to chat about the BNG process in more detail, please get in touch.

Further reading

25 Year Environment Plan

Biodiversity Net Gain: Good practice principles for development. A practical guide. 2019 (CIEEM)

Environment Bill 2020 (GOV.UK)