Biodiversity Net Gain (BNG)

Biodiversity Net Gain is an approach to development that leaves biodiversity in a measurably better state than before.

Instead of simply avoiding or reducing ecological harm, BNG requires you to quantify the habitats on a site, assess how a development will change them and then demonstrate that the finished scheme delivers an overall increase in biodiversity compared with the baseline.

This is usually measured using an official biodiversity metric that converts habitats into numerical “units”. By comparing the baseline units with the post-development units, and factoring in habitat condition, distinctiveness and strategic importance, it is possible to show whether the project achieves the required net gain.

BNG has moved from being good practice to a firm expectation in planning policy and, for many developments, a legal requirement.

Biodiversity Net Gain is increasingly required by local planning authorities as part of planning applications, especially for residential, commercial and infrastructure developments that result in habitat loss or change.

Many councils now expect applications to include a completed biodiversity metric calculation, a clear strategy for delivering net gain on-site or off-site, and long-term management proposals. In practice, BNG often comes into play when greenfield land, semi-improved grassland, hedgerows, trees, ponds, or other semi-natural habitats are affected.

It can also be relevant on previously developed land where pockets of valuable habitat have developed over time. If your planning officer, validation team or policy documents refer to BNG, biodiversity metric, net gain units or habitat creation targets, you will almost certainly need a structured BNG assessment and plan to support your application.

Our BNG service begins with establishing a robust baseline for your site. Using field survey data and habitat mapping, we classify habitats in line with the relevant biodiversity metric and assess their condition, distinctiveness and area or length. This baseline is then entered into the metric to generate a clear, numerical picture of the existing biodiversity value.

We review your development proposals, work with your design team to understand layout and infrastructure, and translate the proposed habitat losses, changes and creations into the same metric. This allows us to calculate the net change in biodiversity units and see whether the project delivers the required level of gain.

Where there is a shortfall, we explore options to adjust the layout, improve the quality of retained habitats, introduce new habitat areas, or incorporate features such as wildflower grassland, native planting, hedgerow creation, ponds and other enhancements, always in a proportionate and realistic way for the site.

If on-site options are limited, we can advise on off-site or unit-based solutions in line with policy. The outcome is a clear BNG strategy and metric calculation that can be submitted to the planning authority, often supported by an accompanying Habitat Management and Monitoring Plan that shows how created and enhanced habitats will be established and maintained over the long term.

We approach Biodiversity Net Gain as a design opportunity rather than simply a constraint. By getting involved early, we can help shape layouts, open space, landscaping and drainage features so they work for both biodiversity and the wider scheme objectives.

We focus on measures that are deliverable on the ground, manageable over the required time period and aligned with the character and context of the site. Throughout the process we keep communication clear and accessible, explaining the metric results, the implications of different design options, and the most efficient ways to achieve the target net gain.

Our aim is always to produce a BNG solution that satisfies policy and legal requirements, supports the planning case and adds genuine ecological value, without imposing unnecessary complexity or cost.

If you have been asked for a BNG assessment, we can help.

When you contact us, please include the site address and postcode, a brief description of your proposal, any planning reference or ecology-related comments from your local authority and an idea of your timescales or key deadlines.

We will review the information and provide clear advice and a fixed-fee quote for your BNG ecology survey.