Biodiversity Net Gain: A Diverse New Era for Development and Nature

Developers and landowners have been grappling with the intricacies of biodiversity net gain (BNG) legislation for the last year – and while significant challenges remain, there has been considerable progress.

This groundbreaking mandate has represented a significant shift in how development interacts with the natural world since it was firmly embedded in the fabric of UK planning regulations.

While the policy was introduced with bold intentions – to halt biodiversity loss and embed ecological thinking into development – is it working? At CSX, we have found its implementation has revealed a landscape as uneven as the one its creators hope to restore.

But there are plenty of positives, too. Here, our expert team examines the law’s implementation, the successes and challenges – and what the future holds…

What is BNG and how is it measured?

Since February 2024, developers have been legally required to deliver at least a 10% improvement in biodiversity – the ‘net gain’ – as part of each building project.

The aim is to ensure the land is left in a measurably better state for nature than before construction. Used in the right way, the BNG regulation should provide and safeguard natural places and green landscaping that can shape and enhance wildlife habitats, hedgerows and rivers and streams.

According to the Department for Environment, Food and Rural Affairs, an official biodiversity metric must measure how many units a habitat contains before development.

This metric is crucial to determine the biodiversity units needed to achieve the statutory 10% BNG. This data is then incorporated directly into planning applications, hopefully streamlining the approval process and ensuring valuable natural habitats are accounted for in development proposals.

Making a positive impact

The legislation’s introduction has marked a pivotal change for conservation, and we have seen many successful instances where biodiversity is at the forefront of development planning.

While it has presented new complexities for developers, BNG has also created opportunities for landowners to generate income by establishing and managing habitat banks. Crucially, all BNG commitments must be maintained and monitored for at least 30 years, a long-term vision for embedding nature recovery in the heart of our built environment.

As BNG experts, CSX has helped clients to maximise the financial value of their sustainable land management techniques with advanced data tools that create and deliver BNG units and carbon offsets.

Advanced data analysis

At CSX, we have pioneered advanced data analysis systems that empower landowners to gain fair returns and to independently verify and track their climate actions, ensuring transparency and accountability as they strive to achieve net zero.

Our innovative platform allows the efficient planning, monitoring and tracking of ecological interventions while bringing BNG offsets to market. These measures are essential in supporting BNG projects and ensuring an efficient process for local planning authorities (LPAs).

Our team harnesses drone technology to create a high-resolution digital twin model of each project’s baseline habitats, ensuring highly detailed and accurate imagery for our in-house biodiversity team to assess and report effectively.

We collect very high-resolution quadrat imagery to help identify the individual species on a project site and also generate canopy height models (CHP) to assess vegetation structure.

The ongoing challenges

It has been an unsettling time for developers and local authority planners alike as they get to grips with the BNG regulatory minefield.

The challenges have included a shortage of relevant legal and ecological expertise within local authorities, leading to planning delays. There is also a lack of accurate and reliable habitat mapping to inform decision-making.

While there are ongoing concerns over local authority fees and the cost and availability of off-site biodiversity units, we have also seen a growing confidence in the policy and more harmonised processes coming to fruition in our work across the country.

BNG might have had a difficult start but the legislation is here to stay – and its long-term commitment to habitat enhancement promises a positive impact on biodiversity for generations to come.

Say hello

Come and join us at the ReGeneration Earth UK Conference 2025 where you’ll find us at stand 34 – or find out more about our BNG work at CSX.