Priority habitat and species in planning

 

A site does not have to contain a protected species or sit inside an SSSI to be important for biodiversity. England also has a statutory list of habitats and species of principal importance, usually called priority habitats and priority species.

These are important in planning because public authorities have biodiversity duties, national policy expects priority and threatened species to be conserved and recovered, and ecological appraisals need to look beyond the boundaries of designated sites.

This page explains what priority habitat means, how the Section 41 list works, why priority status is different from legal species protection, and where it fits alongside PEA, EcIA, Local Wildlife Sites, Local Nature Recovery Strategies and Biodiversity Net Gain.

 

What is a priority habitat?

 

Section 41 of the Natural Environment and Rural Communities Act 2006 requires the Secretary of State to publish a list of the living organisms and types of habitat which are of principal importance for conserving biodiversity in England.

Defra’s published Section 41 list identifies 56 habitats. These range from ancient and native woodland types to species-rich grasslands, heathland, wetlands, rivers, ponds, coastal habitats and open mosaic habitat on previously developed land.

The list is not a set of planning designations. A priority habitat can occur on ordinary-looking private land, outside a nature reserve, SSSI or Local Wildlife Site. That is exactly why an early ecological appraisal matters.

 

How many priority species are there?

 

The Defra Section 41 publication describes the list as containing 943 species. There is a small terminology trap in newer Government biodiversity statistics: the 2026 species-abundance indicator explains that the list comprises 940 species and three subspecies, and it therefore uses 940 species for that particular indicator.

So the familiar total of 943 has not simply turned into a new planning list of 940. The difference is about how the taxa are counted for the indicator. For planning purposes, the sensible starting point remains the current Section 41 list and the ecological evidence for the site.

 

What does Section 41 do?

 

The Section 41 list is closely connected to the public-authority biodiversity duty in section 40 of the 2006 Act, as strengthened by the Environment Act 2021. Public authorities must consider what they can properly do to conserve and enhance biodiversity and must then put appropriate policies and objectives into effect.

Section 41 helps identify the habitats and species that matter to that work. In planning, it provides an important statutory biodiversity reference point for plan-making, site assessment, development management and nature recovery.

It does not mean that every occurrence of a priority habitat is automatically undevelopable. Nor does it create one universal statutory offence of damaging every priority habitat. The planning response depends on the habitat, its condition and extent, the development impacts, other legal protections and the policy context.

 

Priority species are not the same as protected species

 

This distinction is important.

A priority species is on the Section 41 list because it is of principal importance for biodiversity conservation. A protected species has specific legal protection under legislation such as the Wildlife and Countryside Act 1981 or the Conservation of Habitats and Species Regulations 2017.

Some species fall into both categories. Others do not. A species can therefore be a material ecological consideration even where the particular criminal-offence and licensing regime associated with a protected species is not engaged.

For the separate legal framework covering bats, great crested newts, nesting birds and other protected wildlife, see our guide to protected species and planning.

 

Priority habitats in the 2026 NPPF

 

The August 2026 National Planning Policy Framework requires planning policies and decisions to protect and enhance biodiversity and geodiversity rather than looking only at statutory designated sites.

Policy N1 expects plans to identify opportunities for the conservation, enhancement and recovery of landscapes, sensitive waterbodies, habitats and priority or threatened species, including habitat restoration and stronger ecological networks. Policy N2 carries that through to development proposals: they should minimise adverse impacts on biodiversity, include features which support priority or threatened species, and take suitable opportunities to connect to and strengthen ecological networks.

That means an ecologist should not stop at asking, “Is there a protected species?” The relevant questions also include what habitats are present, whether they are priority habitat, what species they support, how they connect to the wider network and whether harm can be avoided in the layout.

 

How do you know whether land is priority habitat?

 

Natural England publishes a Priority Habitats Inventory for many terrestrial and freshwater priority habitats, and it is available through national mapping services. It is extremely useful for screening, but it should not be treated as a perfect site survey or a guarantee that every mapped polygon is unchanged.

Conversely, absence from the inventory does not prove that priority habitat is absent. Habitat can be newly identified, restored, too small or otherwise not reflected in a national dataset.

For a development site, the appropriate route is normally ecological survey and habitat classification by a competent ecologist. Our Preliminary Ecological Appraisal and EcIA guide explains how that evidence is normally assembled.

 

Priority habitat and Biodiversity Net Gain

 

Biodiversity Net Gain and priority-habitat policy overlap, but they are not the same exercise.

The statutory biodiversity metric records habitat type, condition, distinctiveness and strategic significance. Many priority habitats have high biodiversity value, so losing them can create a substantial metric consequence. But a 10% BNG calculation is not a licence to damage ecologically important habitat.

The planning authority still has to apply the mitigation hierarchy and relevant national and local biodiversity policy. Harm should first be avoided, then mitigated, with compensation as the last resort. Some particularly difficult-to-replace habitats are treated separately as irreplaceable habitat, where the BNG regime uses bespoke compensation rather than ordinary metric trading.

 

How does priority habitat relate to Local Wildlife Sites?

 

They often overlap, but neither status automatically creates the other.

Local Wildlife Sites are locally selected non-statutory sites. Current Government guidance recognises that many Local Sites contain priority habitats or species, which is unsurprising: those features often form part of the reason a site is locally important.

But priority habitat can exist outside a Local Wildlife Site, and a Local Wildlife Site may contain a wider mix of locally important features. A planning search should therefore check both mapped site designations and habitat evidence.

 

Priority habitat, LNRS and ecological networks

 

Local Nature Recovery Strategies provide a strategic spatial framework for recovering nature. Priority habitats and species are central to that wider picture because recovery is not just about protecting isolated sites; it is also about restoring, expanding and reconnecting habitat.

A development affecting a small piece of priority habitat may therefore matter for two reasons: the direct loss of biodiversity and the effect on a wider ecological corridor or recovery opportunity.

 

What should an applicant check?

 

1. Run an early constraints search for designated sites, priority-habitat mapping and local ecological data
2. Commission the right ecological appraisal before the layout is fixed
3. Ask whether any habitat on site is Section 41 priority habitat rather than relying only on protected-species records
4. Check the local plan and LNRS for local habitat networks and recovery priorities
5. Apply the mitigation hierarchy by avoiding important habitat before relying on mitigation or off-site compensation
6. Coordinate the ecology and BNG work so the habitat baseline, design and biodiversity metric tell the same story
7. Check for stronger overlapping controls including SSSI, Habitats Regulations, protected species and irreplaceable habitat

 

Key sources

 

• Defra: Habitats and species of principal importance in England
• Natural Environment and Rural Communities Act 2006, section 41
• Defra: Complying with the biodiversity duty
• National Planning Policy Framework, August 2026

Conservation, Heritage & Protected Sites

 

Priority Habitat Page Added: 28th August 2026