What is biodiversity net gain?

Biodiversity net gain, or BNG for short, is a new statutory mechanism for ensuring developers provide overall improvements for biodiversity as part of their developments. In effect, it is a way to create or improve natural habitats as mitigation for building schemes.

Although some Local Authorities have been operating a voluntary BNG scheme for a while, it became mandatory this week (12^th February) for major developments across England. That means that all major developments now must provide at least a 10% uplift in biodiversity for 30 years as part of their scheme. Mandates for other types of developments are expected later this year, or by the end of 2025.

How do we measure biodiversity?

Biodiversity is measured using a metric produced by Defra. This tool is best left to trained ecologists as it is quite complicated, but it essentially uses habitats as a proxy for overall biodiversity. By feeding the metric information on habitat size, condition, distinctiveness and location, you will be able to get a figure for how many biodiversity ‘units’ that area of habitat is worth.

Before a development, developers will usually hire an ecologist to do a baseline survey of their site to determine how many biodiversity units are currently offered, and they’ll also work out how many biodiversity units will be offered after development.

Where do landowners fit in?

The number of credits on a development site is known as ‘on-site’ credits. Often, even with the creation of new habitat features, development schemes will result in a reduced number of on-site credits. When this happens, developers then have to look elsewhere to deliver ‘off-site’ credits. Some developers will have their own land on which to do this, but often we are seeing them coming to agreements with other landowners to deliver their 10% uplift for 30 years.

As a result, a market in selling biodiversity credits to developers has appeared. It’s hard to pin down exactly how much a biodiversity credit will be worth in Northumberland, as there has been no voluntary market here and it depends on the specific habitats and demand, but we’ve heard figures of between £15,000 - £30,000 per credit. Given these figures, BNG is potentially a very good source of green finance for land managers to use to fund nature’s recovery on their land holdings.

NWT is already developing a bank of sites to offer this. If you’d like to find out what we offer, you can find more information on our website.

How do I get involved?

If you are a land manager, and you think you’d like to sell some biodiversity credits, the first thing you need to do is get a baseline survey done. EcoNorth, NWT’s ecological consultancy, offer this service, as do many other consultants.

Your chosen consultant should provide you with a baseline metric assessment, and help you to design a scheme that delivers increased units. The number of increased units is what you can sell on the market. For example, if your site offers 100 credits before any improvements are made, and it’s expected that after improvements that will increase to 120 credits, you can then sell the uplift of 20 credits.

You’ll also need to find a developer to sell your credits to, or you can make use of one of the many intermediary services that aim to link up developers and land managers. Once you’ve found one, you will need to agree to a sale price that covers management costs of the habitat for 30 years, and sign a legal agreement with the developer and the responsible body. You may wish to take some legal advice on this, as conservation covenants will bind you and any other future landowners to the agreement.

Some land managers may take a deposit from developers up front to reserve credits, as land for BNG is usually identified early in the planning process and it can take years for planning to be approved. You would then take the remainder of the payment once planning has been approved. At this point, you’ll be ready to deliver your habitat creation/improvement plan!

Where can I find more information?

There is lots of information available online for land managers on BNG. For example, Defra have written guidance for developers and land managers, available here. Natural England has also produced a brochure.

If you’re considering BNG as an option, an ecological consultant will also be able to give you initial advice.