What is biodiversity net gain and how can you achieve it on your development?

The ongoing need to make the built environment more sustainable is at the top of the agenda in the property development and construction sector. An important way to do this is improving the biodiversity of our developments to regenerate habitat and leave the environment in a measurably better state than it was in before development.

Biodiversity underpins ecosystem services which provide everything that we need to survive. The more pressure we put on those systems, the higher the risk of upsetting the balance and worsening the climate crisis. By working to ensure biodiversity net gain (BNG) is achieved on all building and development projects, the property sector can do its part to minimise the impact of new developments. Now, with new legislation coming into force, improving biodiversity is not just a preference or a possibility – it is a legal requirement.

Read on to learn more about what BNG involves, what the legislation means for you and what steps you can take to fulfil the requirements from January 2024.

Biodiversity net gain is a way of delivering measurable improvements to the environment through habitat creation and enhancement that help nature recover. In the past, many developments would negatively affect the surrounding biodiversity, but the process of achieving a net gain in biodiversity means that a site’s completion can enhance ecological value rather than detract from it.

While achieving biodiversity net gain is possible through both on-site and off-site measures, the Mitigation Hierarchy should be adhered to. The Mitigation Hierarchy details the steps needed to be completed before off-site mitigation can be utilised:

• Avoid – Areas with high ecological value should be avoided and protected within the design wherever possible.
• Minimise – Any impact on on-site biodiversity should be minimised through protection measures.
• Restore – Losses of biodiversity should be compensated for on-site through habitat creation and enhancement.
• Mitigate – Any further biodiversity losses that cannot be compensated for on-site should be mitigated through off-site mitigation. 

The National Planning Policy Framework was updated in 2021 to say that “opportunities to incorporate biodiversity improvements in and around developments should be integrated as part of their design, especially where this can secure measurable net gains for biodiversity.”

This was followed by the Environment Act 2021 which mandates a legally binding biodiversity net gain of at least 10% on or near new developments, and targets to halt species decline by 2030. This gain is measured using the Biodiversity Metric 4.0.

Most importantly for architects, housebuilders and developers, it should be noted that this minimum 10% requirement comes into force in January 2024 across England (originally scheduled November 2023 but delayed by two months). The initial transitionary period that allowed developers to get up to speed is coming to an end, and all involved must soon incorporate BNG measures into their projects to meet their legal responsibilities.

As of January 2024, the requirement for a 10% biodiversity net gain on all developments means that architects, housebuilders and developers will need to change their approach and plan for nature right from the outset. Without it, your development will not receive planning permission and you will have to go back to the drawing board – a process which comes with a large financial and time cost.

Getting it right from the start relies on making informed, data-driven decisions on your project to measure the existing biodiversity and develop a credible plan to increase it over the course of the development. You will have to identify constraints and know how to work around them to increase the biodiversity of the site. Your plan will also need to outline how the 10% gain will be managed and maintained for a minimum of 30 years after development. This will then be secured via a planning condition.

Different habitats need different solutions to offset the loss during development. High-value habitats such as wetland or woodland can require a huge amount of work to replace and expand. This is especially the case in built up areas of sites with little room to manoeuvre which may present a real challenge and limit your options.

However, there are some measures which can be applied to every site which can help you achieve the necessary biodiversity gains. 

Within the British Standard for BNG (BS8683:2021 – Process for designing and implementing Biodiversity Net Gain – Specification) species enhancements such as eco-habitats are listed as a way to ensure a holistic design that provides space for various species. 

Our eco-habitat range was created in partnership with Habibat – a leading manufacturer of species enhancements including bird and bat boxes – to provide the most comprehensive range of wildlife products available on the market, produced in the UK to standard brick sizing for ease of installation and optimised to increase biodiversity by attracting a number of different species.

Our wildlife boxes are durable, discrete and can be produced as a bespoke solution for your development. Our boxes can be faced in any brick type, regardless of manufacturer, or created with stone finish or made suitable for render.