Biodiversity Net Gain – What is it and are Wildflowers the Answer?

From January 2024 onwards, developers in England will be required to deliver a 10% ‘Biodiversity Net Gain’ (BNG) when building new housing and industrial or commercial developments. This is in an attempt by the government to make new infrastructure nature positive.

Developments will be required, by law, to deliver a positive net gain for the local environment, by creating or enhancing habitats and green spaces. Biodiversity Net Gain for smaller sites will be applicable from April 2024, and for Nationally Significant Infrastructure Projects from 2025.

Having already been pushed back and delayed, questions are still circling the new legislation. So, let us try and provide some insight.


Biodiversity Net Gain (BNG)

There are numerous aspects of understanding BNG, and far too much information to cover all in one place. The basic concept, as touched upon, is to ensure that new development projects result in a net increase, rather than a loss, in biodiversity.

Two of the key elements of the plan, and where many of the queries come from are:

The Biodiversity Metric – This is used to measure and quantify habitats into the form of biodiversity units, with the outcome being to achieve a net gain in these units. This provides a (reasonably) simple way to quantify the impact of a development on biodiversity.

The Biodiversity Metric consists of four key factors:

  • Habitat Size – How large or small is the habitat?
  • Habitat Condition – How well is the habitat functioning, compared to one in full working order?
  • Habitat Distinctiveness – Is the habitat of particular ecological importance?
  • Location – Is the habitat a local priority or located in a priority area for habitat creation/enhancement?

It should be noted that the Biodiversity Metric is a tool that should be used with somebody competent – such as an ecologist.


Mechanisms of BNG Delivery –

In order to achieve a biodiversity net gain within a development, a developer has three options. These are:

  • On-Site Units – These are delivered on the site of the development in question through habitat creation, enhancement via landscaping and green infrastructure. This method is to be prioritised where possible.
  • Off-Site Units – These are delivered by working with external public and private landowners, again through habitat creation and enhancement, in instances where onsite gains cannot be achieved. So, if there isn’t any opportunity to enhance biodiversity on the development site, developers will work with landowners to ensure the net gain is achieved. While it is preferred that this is undertaken on land within the same planning authority as the development site, it is not strictly limited to this.
  • Statutory Credits – Used only as a last resort, where on-site and off-site Biodiversity Net Gain cannot be achieved, developers can purchase BNG credits to off-set the habitat that is removed or destroyed in the building process. This is by far the most expensive route, with pricing higher to deter developers from taking this route.

To meet these criteria, there are several different habitat options for developers. Grasslands, heathland & shrub, woodland & forestry and lakes, with different habitats providing varying amounts of units.

Grasslands (wildflower meadows) are expected to be a key option.


How Can Wildflowers Help?

With 97% of the UK’s grasslands being destroyed since the 1930s, it comes as no surprise that wildflower meadows are an important option within BNG. With so many grassland habitats lost, creation or restoration provide a crucial opportunity for developers to return what there once was.

A key element on why wildflowers create an opening is the sheer number of species in a wildflower mix. With much of the BNG metric for grasslands being based on the number of species per square metre, wildflower meadows present a golden opportunity to integrate a high number of plant species into the area that they are planted. With more species meaning more gain!

Let’s say, for example, a developer looks to restore a grazing paddock off-site to a wildflower meadow. The current field will contain a limited number of, mostly, grass species with possibly a few legumes or flora. Once the restoration works have taken place, the grassland will be densely populated with a multitude of species, unlike the grazing paddock, and therefore significant gains will be made.

The increase in plant species will then see a direct link to an increase in pollinator species, helping to further increase the biodiversity on the site.

As well as rural areas, wildflowers are a great option for urban developments. It is fairly common in new housing to see parkland build into the infrastructure to provide a walking area for the new residents. This can quite easily include a meadow with paths running through.

A lot of the scheme is about utilising the baseline of what is already there. For example, if a landowner is looking to take a grazing or arable field out of production to put in a wildflower meadow for off-site Biodiversity Net Gain, the first choice would likely be the arable field because there is very little habitat as it currently stands – therefore creating a greater uplift for biodiversity net gains.

On the other hand, if a meadow was already in place, it would be a considerable challenge to increase the biodiversity, as the ecological baseline is already high. This presents the opportunity for a landowner to utilise unproductive land for alternative income streams to the benefit of our natural habitats.


Native vs Non-Native

One thing to take extra care of when wildflowers are concerned is the provenance of the seed. Does the buyer know where the seed originated?

Unfortunately, within the wildflower market, there is no regulation for seed production and distribution. This can have damaging effects on long-standing ecosystems.

It is thought that of 3,500 British plant species, non-native plants now outnumber native species by 51% to 49%, with more than half of Britain’s native plants in decline. Many of these non-native plants can become invasive, outcompeting the native species.

The majority of these native species have adapted to grow in a climate and environment over thousands of years, evolving alongside native wildlife. Many of the valuable pollinators that are so important for our own food production rely on these specific native species, so seeing them in decline is bad news for everybody.


How Bright Seeds can Help with Biodiversity Net Gain? 

At Bright Seeds, we have the skills and machinery to harvest existing grassland meadows, enabling us to provide native seed and accurate provenance information. Although it doesn’t impact the metric, it is likely to keep the ecologists and planning authorities on side to aid in approval of the application. Very few wildflower seed suppliers are able to provide this option to buyers.

It is often the case, when buying generic wildflower seed from a supplier, that the seed that has been purchased from abroad or hundreds of miles away in the UK, without consideration local provenance to your site.

So, speak to Bright Seeds about any upcoming projects that may require wildflower seeds, and we can look into providing seed from as nearby as possible.

You can also click here find out more information about our harvesting and processing of wildflowers.


For more in depth information on Biodiversity Net Gain, take a look at the Natural England brochure here