On February 12th 2024 it became a legal obligation for all developments in England to demonstrate a 10% net gain in biodiversity.  This requires developers to show  how they will deliver an increase in natural habitats and ecological features over time, which goes above the habitat originally on site.

In this guide, we take a closer look at some of the definitions and what this means for developers.

What is Biodiversity?

Biodiversity is a measurement of the variety of life within a particular habitat or ecosystem. Biodiverse systems are rich in life, supporting a wide variety of species. Not only do they showcase environmental health, but they also contribute towards it in a positive feedback loop.

What is Biodiversity Net Gain (BNG) 

Biodiversity net gain is the term used to describe the process of increasing the overall biodiversity value of a development site. In simple terms, it means leaving nature in a better state than when you started the project.

 As of February 2024, legislation now means that all qualifying developments in England  need to achieve a demonstrable Biodiversity Net Gain of at least 10%. There are limited exceptions detailed here: https://www.gov.uk/guidance/biodiversity-net-gain-exempt-developments

How is BNG measured

 BNG is measured using the Statutory Biodiversity Metric. This metric must be completed by a qualified and experienced ecologist and will need a site visit. For many habitats, this site visit will need to take place during the growing season (April - August)  to be robust and accurate – so plan accordingly and speak to ecologists early on in the process.

What is a biodiversity metric?

A biodiversity metric is a tool used by ecologists to measure changes in biodiversity. Several such tools have been developed, most recently the Defra Statutory Biodiversity Metric as above.  This provides a benchmark for all developers to follow to understand the key components of an area’s biodiversity value.

These metrics currently are only concerned with habitats and do not take protected species into consideration.

Metrics assign every habitat on a site a ‘unit value’ according to its relative value for biodiversity. This enables a comparison between the existing value of a site and what will be delivered through development or management.

Biodiversity metrics can help to determine the value of an area of land. This is sometimes referred to as biodiversity banking.

What does a biodiversity metric represent?

The basic aim of completing a metric is to ensure your development plans increase the overall value of a site. This can be achieved through onsite measures, offsite measures or a combination of the two.  If a net gain still isn’t secured it’s still possible to offset the loss away from the site.

The value of a habitat will be measured considering the following factors:

• A habitat’s size

• A habitat’s distinctiveness

• The diversity or rarity of the habitat and species found

• The strategic significance of a site and its ecological importance locally

• The condition and quality of the habitat

• The connectivity of the site and how the habitat is connected to other areas

• The local importance of the habitat site

What are the Three Types of Biodiversity Unit?

Biodiversity (measured in ‘Biodiversity Units’ by the Statutory Biodiversity Metric) is split into three types:

·      Area habitats (measured in hectares and depicted as polygons: habitats like grassland, woodland, lakes and ponds);

·      Linear habitats (measured in km, terrestrial linear features like hedgerows and treelines); and

·      Watercourse habitats (measured in km, aquatic linear features like rivers and their associated 10m riparian corridors).

 Each of the three types of biodiversity are measured separately by the Statutory Metric. To achieve a 10% net gain on a development site, a 10% net gain needs to be achieved in each of the above separately. A significant net gain in hedgerows cannot be used to offset a net loss of area habitats for instance.

How Can BNG be Achieved on Development Sites?

Biodiversity net gain is demonstrated by presenting findings in a metric.

Biodiversity metrics allow local planning authorities (LPA) to interpret the baseline and proposed biodiversity value of a site and ensure the correct percentage of biodiversity net gain is achieved.

 BNG metrics allow for a universal way to measure biodiversity that can be used across the board.

 BNG can be achieved in a number of ways including:

·      Creating new habitats alongside your development;

·      Protecting and improving existing habitats within a development site;

·      Creating/improving habitats near the development site as part of a wider project;

·      Financing third party creation/improvement of habitats near the development site (e.g. through a biodiversity unit broker. An Ecology by Design partner company, Civity can help with this.

·      Buying  Statutory Biodiversity Credits.

Where habitats are created or improved away from a development site, this is called ‘Biodiversity Offsetting’.

 Avoiding impacts in the first place will always be the preferred option, followed by on-site compensation, then off-site compensation, then the buying of Statutory Credits.

Early involvement of an ecologist or consultancy should determine what’s possible on your site and identify any constraints regarding improving the biodiversity value. It should be considered as early as possible as your development will not pass planning permission if net gain is not built in to your development plans.

How Ecology by Design can help

As biodiversity net gain experts, we can help you to understand the baseline value of your site by conducting a preliminary ecological appraisal. This will help you to identify any constraints and opportunities within the site. We can also identify suitable sites for biodiversity offsetting if net gain isn’t entirely achievable onsite. We’ll work to find you the most efficient solution and liaise with planning authorities, estate owners and other stakeholders to ensure the best possible outcome.

Summary

Biodiversity Net Gain (BNG) is now a legal requirement for almost all developments. Involving the services of an ecology consultancy at the earliest opportunity can save time and ultimately money. Ecology by Design can offer practical and pragmatic solutions to companies and organisations progressing any kind of planning application. For an informal chat, get in touch here: hello@ecologybydesign.co.uk