The construction industry in the UK is undergoing a significant transformation. Introduced under the Environment Act 2021, the 10% Biodiversity Net Gain mandates that major development (including housing, industrial, and commercial projects) must result in a measurable net-gain to biodiversity.

What Is Biodiversity Net Gain?

Biodiversity Net Gain is an approach to development that ensures that habitats for wildlife are left in a measurably better state than they were before the development.

Developers must use the DEFRA biodiversity metric to calculate habitat value before and after development, ensuring a measurable improvement. Additionally, Biodiversity Net Gain must be maintained for at least 30 years, either on-site or via registered off-site units.

Why does it matter?

The UK is one of the most nature-depleted countries in the world. Since 1970, species diversity across the UK has declined by 19% and nearly one in six species are at risk of extinction. Construction and the Built Environment is estimated to be responsible for 30% of Biodiversity loss. As such, the sector has a responsibility to implement initiatives that aim to reduce or even reverse this loss.

For developers, this represents a significant change in how projects are planned, costed, and delivered. But it also offers opportunities such as improved community relations, enhanced green infrastructure, and future-proofed designs.

Measuring Biodiversity

Biodiversity is measured using Standardised Biodiversity Units to assess the Biodiversity Value of a given area. This metric accounts for the size, quality, location, and type of a given habitat.

When beginning a new project, organisations must first perform a baseline assessment to determine the biodiversity of an area. Organisations must clearly demonstrate how many habitats are contained before the development takes place, and the Biodiversity Net Gain following the project.

Design & Development

Once a baseline has been established, organisations may approach BNG in a variety of ways. On-site biodiversity development through the introduction of features such as species-rich grasslands, native hedgerows, woodland planting, ponds, or green roofs can be integrated directly into the design of the site.

Collaboration between ecologists, landscape architects, and planners is essential to ensure that proposed enhancements are achievable within the site’s constraints while aligning with planning policy and the DEFRA biodiversity metric.

For instances where on-site biodiversity enhancement has been deemed insufficient or unfeasible, organisations may pursue off-site solutions to meet their BNG requirements. Off-site BNG involves securing biodiversity gains on land separate from the development site, either through land owned by the developer, partnerships with third-party landowners, or by purchasing biodiversity units from a habitat bank.

Site selection is critical and must be guided by local ecological priorities, spatial strategies, and the DEFRA metric’s location-based multipliers, which favour proximity to the development.

Early engagement with landowners, conservation bodies, and local planning authorities helps ensure that off-site projects are appropriately designed, ecologically sound, and aligned with broader nature recovery objectives.

Demonstrating 10% Net Gain

The same metrics used to establish a baseline, are also used to assess and demonstrate 10% Net Gain. By applying a consistent methodology before and after development, organisations can transparently demonstrate how biodiversity losses are mitigated, and gains are achieved.

Accurate use of the metric is essential throughout the design and delivery phases, and all calculations must be evidenced and submitted within a formal Biodiversity Gain Plan for planning approval.

Long-term Management

Long-term management is a critical component of any BNG project, ensuring that biodiversity gains are sustained and habitats continue to deliver ecological value for a minimum of 30 years.

This requires a comprehensive Habitat Management and Monitoring Plan, which sets out how habitats will be maintained, enhanced, and monitored over time. Management activities may include controlling invasive species, maintaining structural diversity, replanting where necessary, and adjusting practices in response to monitoring outcomes.

What Counts Towards the 10%?

• Creation of new habitats
• Enhancement of existing degraded habitats
• Off-site improvements on nearby land (if on-site gains are not feasible)
• Purchase of government biodiversity credits as a last resort

Learn More

To learn more about how SustainIQ can help your organisation respond to 10% Biodiversity Net Gain requirements, arrange a demo here.

About SustainIQ

SustainIQ is an integrated ESG reporting platform that unifies all aspects of an organisation’s sustainability activities within a single environment. Businesses use SustainIQ to measure, monitor, and report on their social, economic, and environmental performance in real time.

Our software saves sustainability professionals from wasting time chasing teams, sites, and regions for reporting information. No more unreadable spreadsheets, awkward (and incorrect) calculations, and endless report building. With SustainIQ, simply pull, input or bulk upload data and get access to your custom-built report at touch of a button.