What is biodiversity net gain (BNG) and why is it important?

1 million species are at risk of becoming extinct within our lifetime. That’s 10% of life on Earth.

There’s been a 60% reduction in wildlife since the 1970s alone.

But for some reason, land sustainability and biodiversity don’t get the attention they deserve when compared to climate change and carbon emissions.

The truth is, biodiversity is as important as climate change. Maybe more so.

Life on earth is all connected. If one species dies it has a domino effect, and if the wrong species dies, that can get dangerous quickly. Loss of pollinators means loss of food sources.

In a report from the UN on biodiversity, PBES Chair, Sir Robert Watson said, “The health of ecosystems on which we and all other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide”.

Regulators, local governments, and entire nations are now implementing legal requirements and other frameworks to help reverse this trend.

COP 15 for example, the UN’s biodiversity conference, the UK’s Environmental Bill where they introduce biodiversity net gain (BNG) and regulations around it, and the EU’s 2030 biodiversity plan.

What is biodiversity net gain (BNG)?

Biodiversity is defined as the variety of life on earth or a given habitat.

BNG takes that and puts a good land steward spin on it. According to local government UK, “Biodiversity net gain (BNG) is an approach to development, and/or land management, that aims to leave the natural environment in a measurably better state than it was beforehand.”

This is important because it promotes a sustainable way to ensure long-term food production and natural resource production for years to come. BNG guards against over optimization of land.

For example, if everything was farmland, we wouldn’t have pollinators which means no crops.

If several housing developments go up in a region and it destroys the natural habitat, it can break the food chain causing a cascade of issues.

In other words, be a sustainable land steward and leave your land holdings better than you found them.

From late 2023 onwards in the UK, this will become a requirement for any new projects to consider biodiversity of their plot, leave it better than they found it, or improve by at least 10% elsewhere.

Very simple concept, but it’s difficult to achieve because the world lacks a unified metric for biodiversity.

How to measure biodiversity net gain (BNG)

Unlike carbon, which is easily quantified (if not easily measured), how do you measure life in a specific habitat, short of counting individual species?

Not only that, but biodiversity improvements can take years to fully take hold. Just think about how long it can take a forest to fully mature. That means constantly going out and assessing a plot, looking for small changes in order to report progress.

With the BNG efforts out of the UK, they’ve developed a biodiversity metric, based on a scorecard approach to assessing, measuring and improving your biodiversity net gain They cleverly call it biodiversity units.

But even that isn’t a perfect solution, it’s more progress over perfection.

We did a deep dive into this measurement system and how to use it, but the basics are:

• Instead of a species-based approach, it’s a habitat-based approach, for example modified grassland or meadow. Much more pragmatic to assess, and balances micro vs macro trends.
• Focuses on the condition of that habitat, not just the type. A habitat in excellent condition is going to have a better biodiversity score than the same habitat in poor condition.
• Certain habitats are ranked higher than others because of the diverse ecosystems they promote or strategic significance according to the local government.
• How surrounding ecosystems connect to one another plays a factor as well.

Habitats, condition, and connectivity all get a score. If you want to improve the biodiversity net gain of that plot you have to adjust one of those three variables.

Either change the habitat (while also keeping in mind connectivity) or improve the condition of a habitat. And of course, size matters. A 1,000-hectare plot will naturally shift your overall biodiversity net gain score more than a 10-hectare plot.

5 tips to improve your biodiversity net gain (BNG)

1. It can take a very long time for an ecosystem to develop. It’s usually better to maintain and improve a habitat rather than trying to completely start from scratch.
2. Look for quick wins. For example, adding a pond or wetland to a housing development. These don’t take long to mature and have a relatively high BNG score. Or changing a monoculture grassland to a natural grassland, simply adding new species of grass, or changing pastoral grassland to a meadow. These are all relatively quick changes that can make a big impact.
3. Always try and restore biodiversity within the same region as any disruptions. If construction completely destroys a habitat, it’s important to try and make up for it nearby to keep the regional ecosystem chain intact.
4. Don’t just look at the score. Biodiversity is about managing land in a more sustainable way. This means maintaining pollinator habitats and sustainably maximized resource production like food or timber.
5. Don’t over optimize. Climate change and greenhouse gases (GHGs) tend to steal the spotlight, and for good reason, they are a major threat. But you shouldn’t optimize only for the habitats that absorb the most carbon. While that should be part of the equation, landowners have to strike the balance between biodiversity, sustainable ecosystems and carbon absorption for the best long-term results.

There are technologies available to help you better assess, measure, track, and report on your biodiversity net gain. Check out our guide to help you pick the best option for you.