BNG planning alert: New guidance on irreplaceable habitats

Since irreplaceable habitats are, like the name says, quite difficult, if not impossible to replace, developers know to steer clear of them or risk massive difficulty.

The UK Government further defines irreplaceable habitats as habitats that are not just difficult but may also take a very significant amount of time to restore, recreate, or replace once destroyed. The challenge may be due to age, uniqueness, species diversity or rarity.

Defra provided initial guidance on how Biodiversity Net Gain applies to irreversible habitats shortly after the 10% BNG mandate of the Environment Act 2021 took effect in February 2024. In September, updates to those guidelines were issued, which we will examine below.

However, for those new to locating project development sites that do not infringe on irreplaceable habitats, or determining what to do if you run into them, the “Am I working with an irreplaceable habitat?” blog link below provides a quick look at what to watch out for, based on the full, initial set of guidelines.

Updates to initial guidance

In general, the policy around irreplaceable habitat and Biodiversity Net Gain remains unchanged: The guidance was updated to make it clearer how irreplaceable habitat is dealt with under Biodiversity Net Gain, and to explain what information is needed at planning application stage.

Development on an irreplaceable habitat

Because irreplaceable habitats include some of the country’s most valuable terrestrial and intertidal habitats it is going to take some pretty exceptional circumstances to earn permission to disturb them.

It won’t be as simple as compensating with 10% BNG. The government as the name suggests, considers the biodiversity value of these habitats irreplaceable.

Instead, if you may cause any loss of an irreplaceable habitat, plan to spend time with your Local Planning Authority to create a plan that will minimise adverse impacts and present a compensation strategy.

New: Compensation rules

As mentioned, getting permission to disrupt an irreplaceable habitat area will require time spent with your LPA to plan a strategy that ensures you adhere to new compensation rules:

• You must plan for compensation that is relative to your baseline habitat type.
• You must gain LPA agreement to irreplaceable habitat compensation in your planning application. (This is not guaranteed as LPAs will assess plans on a case-by-case basis.)

Project planning: Consider irreplaceable habitats from the start

Think about irreplaceable habitat at the design and planning stage of your project, and look at how to avoid any adverse impacts.

At the planning stage, you will need to satisfy the minimum information requirements, including providing a:

• Description of any irreplaceable habitat on site at the date of the planning application.
• Plan of existing irreplaceable habitat on site at the date of the planning application.

Your Local Planning Authority may ask you for more information related to Biodiversity Net Gain and wider planning policies designed to protect the environment.

Record irreplaceable habitat in your BNG calculation

• When you are expecting no impact: As you work with Defra Statutory Biodiversity Metric tool to design for BNG, be sure to record any irreplaceable habitats on your site. Report irreplaceable habitat even if you plan to build your proposed development around that habitat and avoid impacting the area.
• When you are expecting adverse impact: Impacts to irreplaceable habitats cannot be measured by the Statutory Biodiversity Metric and they will be automatically removed from your baseline calculation in the tool. Do not record any bespoke compensation action for losses of irreplaceable habitat within the enhancement or creation sheets of the biodiversity metric.
• Where you are expecting to make BNG enhancements: Where there are no losses or deterioration of irreplaceable habitat, you must record enhancements in the Statutory Biodiversity Metric calculation tool and include them in your baseline calculations. These enhancements:
• • May contribute towards the calculation of post-development biodiversity units.
  • Must be ecologically appropriate and not have any adverse impacts on irreplaceable habitats.
• When your project site includes irreplaceable and non-irreplaceable habitat: You must achieve at least 10% BNG on non-irreplaceable habitat on your development site. This is in addition to agreeing bespoke compensation for impacts on irreplaceable habitat, which cannot count towards your BNG requirement.

Record irreplaceable habitats in your biodiversity gain plan

If your LPA grants you permission for project development on a site that includes irreplaceable habitats, you will need to provide details in your biodiversity gain plan for your development. These details should include:

• Type, extent, and condition of any irreplaceable habitat on the site — before development.
• Any changes in irreplaceable habitat type, extent, and condition you expect as a result of development.
• Actions you have taken to minimise adverse impacts to irreplaceable habitat.
• A compensation plan.

Dive into the details

More supporting details regarding Irreplaceable Habitats and Biodiversity Net Gain, are available in government publications:

• For the definition and full list of Irreplaceable Habitats for BNG in the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024.
• For information concerning special arrangements that apply for the treatment of irreplaceable habitat for phased development and permissions granted under section 73 of the UK Environment Act 2021.
• For more about Biodiversity Net Gain — planning practice guidance.
• For more about BNG and the Statutory Biodiversity Metric — user guide.

Or learn how AiDash can help you accelerate your BNG planning application process.