Irreplaceable habitats
How biodiversity net gain (BNG) applies to irreplaceable habitats.
Applies to England
Biodiversity net gain (BNG) is mandatory from 12 February 2024.
What irreplaceable habitats are
Irreplaceable habitats are habitats which are very difficult (or take a very significant time) to restore, recreate or replace once destroyed, due to their:
- age
- uniqueness
- species diversity
- rarity
They include some of England’s most ecologically valuable terrestrial and intertidal habitats.
The definition and list of irreplaceable habitats for BNG are set out in the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024. The list includes:
- ancient woodland
- ancient and veteran trees
- blanket bog
- limestone pavements
- coastal sand dunes
- spartina saltmarsh swards
- mediterranean saltmarsh scrub
- lowland fens
How BNG applies to development on irreplaceable habitats
Developers should record all on-site irreplaceable habitat in the metric calculation tool.
However, the 10% BNG requirement does not apply when irreplaceable habitats are lost. This is because they are so difficult to recreate and have such a high biodiversity value that it would be impossible to achieve the requirement to increase biodiversity on top of no net loss.
BNG does not change the existing protections and compensation requirements for irreplaceable habitat in planning policy. The national planning policy framework on irreplaceable habitat applies. This means that planning permission for development resulting in the loss or deterioration of irreplaceable habitat will only be granted in wholly exceptional circumstances and where a suitable compensation strategy exists.
What developers need to do
1. Consider irreplaceable habitats at the design and planning application stage
Development affecting irreplaceable habitats requires special consideration at the design and planning application stage. Developers should make sure that:
- they minimise impacts on irreplaceable habitats
- they agree suitable compensation for loss or deterioration of irreplaceable habitats
Provide BNG information
Developers must satisfy the BNG minimum information requirements at the planning application stage. They will need to provide 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
The local planning authority (LPA) will not accept the application without this information.
Follow compensation rules
Special compensation rules apply to these habitats.
Compensation for irreplaceable habitat needs to be relative to the baseline habitat type. The LPA will agree compensation with developers as part of the determination of the planning application, on a case by case basis.
More information is available in the planning practice guidance.
2. Calculate BNG when there are irreplaceable habitats
You must record all irreplaceable habitats on site in the metric calculation tool, regardless of whether or not they will be impacted by the proposed development.
When there are impacts to irreplaceable habitats
Impacts to irreplaceable habitats cannot be measured by the biodiversity metric and they are automatically removed from the baseline calculation when you use the biodiversity metric.
You must not record any bespoke compensation action for these losses of irreplaceable habitat within the enhancement or creation sheets of the biodiversity metric.
There is more information in the statutory biodiversity metric user guide.
When making enhancements to irreplaceable habitats
Where there are no losses or deterioration of irreplaceable habitat, their enhancements must be recorded in the metric calculation tool and will be included in the baseline calculations.
Enhancement works may contribute towards the calculation of post-development biodiversity units.
Enhancement works must be ecologically appropriate and not have any adverse impacts on irreplaceable habitats.
When development sites contain irreplaceable and non-irreplaceable habitat
You will need to achieve at least 10% BNG on any non-irreplaceable habitat present on your development site. This can include through enhancing irreplaceable habitat.
This is in addition to agreeing bespoke compensation for impacts on irreplaceable habitat, which cannot count towards your BNG requirement.
3. Record irreplaceable habitats in the biodiversity gain plan
If planning permission has been granted for development on a site which includes irreplaceable habitats, developers will need to provide details of the irreplaceable habitats in the biodiversity gain plan for the development. This should include:
- the type, extent and condition of any irreplaceable habitat there is before development
- any expected changes in irreplaceable habitat type, extent and condition as a result of development
- a compensation plan
Special arrangements apply for the treatment of irreplaceable habitat for phased development and permissions granted under section 73. There is more information in the planning practice guidance.
Give feedback on this guidance by completing a short survey.