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, compared to climate change and carbon emissions.

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

All life on earth is connected. If one species dies, it has a domino effect, and if the wrong species dies, that can get dangerous quickly. For example, the loss of pollinators means the 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. For example, there’s COP 15, the UN’s biodiversity conference; the UK’s Environmental Bill, which introduced 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 the Local Government Association, “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. BNG guards against over optimization of land. For example, if everything was farmland, we wouldn’t have pollinators, which means we would have no crops.

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

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

In the UK, any new projects are now required to consider the biodiversity of their plot and leave it at least 10% better than they found it (or, depending on offsets, leave a different plot elsewhere 10% better).

It’s a 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 and looking for small changes in order to report progress.

With the BNG efforts in the UK, they’ve developed a biodiversity metric. It’s based on a scorecard approach to assessing, measuring, and improving your biodiversity net gain. These are called “biodiversity units.”

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

• Instead of a species-based approach, it’s a habitat-based approach. Examples of habitats include modified grassland or meadow. That’s much more pragmatic to assess, and it balances micro versus macro trends.
• This system focuses on the condition of the 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, as defined by the local government.
• The way surrounding ecosystems connect to one another is 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.

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, like adding a pond or wetland to a housing development. These don’t take long to mature and have a relatively high BNG score. You could also change a monoculture grassland to a natural grassland, or simply add a new species of grass, or change a 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. 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.