SANGs and recreational disturbance around heathland

Where a new home sits within the zone of influence of a heathland Special Protection Area, the council cannot grant permission until it is satisfied that the extra walking, running and dog exercising will not harm the birds the site was designated for. That is the sang recreational disturbance problem in one sentence. The answer is Suitable Alternative Natural Greenspace, provided at a set quantity per resident, plus a contribution to access management and monitoring, both secured before permission.

Why recreational pressure triggers a habitats assessment

The Conservation of Habitats and Species Regulations 2017 require the competent authority, normally the local planning authority, to consider whether a plan or project is likely to have a significant effect on a European site, alone or in combination with other plans and projects. Where that cannot be ruled out, an appropriate assessment follows, and permission can only be granted if the authority is certain beyond reasonable scientific doubt that the integrity of the site will not be adversely affected.

Lowland heaths are designated for ground-nesting birds such as nightjar, woodlark and Dartford warbler. Ground nests fail when they are disturbed, and dogs off leads in the breeding season are the mechanism. Cat predation from housing close to the boundary is a second pathway, urban fire risk a third, and fly-tipping and trampling complete the list.

Housing generates that pressure permanently. A hundred new homes within walking distance of a heath produce dog walks every day for the life of the development, which is why mitigation has to be permanent too.

Mitigation cannot be used to screen a project out. Following the judgment in People Over Wind, the effect of avoidance and mitigation measures is considered at the appropriate assessment stage rather than at screening, so expect a shadow appropriate assessment to be needed even where the mitigation package is standard.

Zones of influence and how they are drawn

Zones are set locally, based on visitor survey evidence about how far people travel to a site. The Thames Basin Heaths approach is the most developed: net new dwellings within 400 metres of the boundary are not acceptable at all, and those between 400 metres and 5 kilometres need avoidance and mitigation. Other areas, including the Dorset heaths, Ashdown Forest, Epping Forest and the Solent coastal sites, have their own distances and their own strategies.

Do not assume one area's numbers apply to another. Find the authority's adopted avoidance and mitigation strategy or supplementary planning document, and read the zone definitions and the tariffs from that document.

The trigger is usually net new dwellings, which means a replacement dwelling with no net increase often escapes, while a barn conversion creating one unit does not. Tourist accommodation, care accommodation and student housing are treated differently in different strategies, so check rather than assume.

What a SANG has to provide to count

A Suitable Alternative Natural Greenspace is not a park and it is not amenity open space. It has to be somewhere a dog walker chooses instead of the heath, which sets the design brief.

The features that make one work are a circular walking route of a length comparable to a heathland walk, space where dogs can be let off the lead safely, natural and semi-natural character rather than mown grass and formal planting, car parking where people would drive to it, safe access that does not cross a fast road, clear signage from the new housing, and no features that attract a different audience such as formal play equipment or sports pitches.

Quantity matters as much as quality. The Thames Basin Heaths standard of eight hectares per 1,000 new residents is the benchmark most strategies work from, calculated on the net increase in population using occupancy assumptions set out in the local strategy. Confirm the figure and the occupancy assumptions from the authority's own document, because they differ.

Land alone is not enough. The SANG needs a management plan, a funding stream for management in perpetuity, and a body willing to hold it.

Access management and monitoring contributions

The second half of the package is a strategic contribution, usually called strategic access management and monitoring, which funds wardens on the protected site, visitor surveys, bird monitoring, fire prevention and education work.

It is charged per dwelling on a published tariff, often varying by bedroom count, and it runs for a long period rather than as a one-off. Treat it as a fixed development cost at appraisal stage in the same way as the levy, because it is not negotiable in the way a section 106 contribution to a local school sometimes is.

Where a strategy exists, both elements are effectively standardised. That is helpful, because it means the habitats question becomes a checklist rather than an argument, provided you are inside the strategy's scope.

Securing mitigation through a legal agreement

A section 106 agreement is the usual instrument. It will typically require the SANG land to be laid out and open before first occupation, transfer it or secure it by covenant, set up the management funding, and pay the access management contribution on a defined trigger.

Three drafting points repay attention. Make the SANG trigger occupation rather than commencement, so the greenspace exists when the residents arrive. Deal with what happens if the SANG cannot be delivered, with a fallback of purchasing capacity in a strategic SANG. And check whether the authority requires the land to be transferred freehold or will accept a long lease with a management company, because that decision affects the funding structure.

Unilateral undertakings are accepted by some authorities for small schemes buying into a strategic SANG, and they are faster. Ask early.

Schemes too small to deliver their own SANG

A scheme of eight houses cannot deliver eight hectares of greenspace, and nobody expects it to. Councils inside the main affected areas run strategic SANGs and sell capacity by the dwelling, so a small developer pays a per-unit figure covering both the SANG and the access management contribution.

Capacity is finite. A strategic SANG with no remaining capacity blocks applications until the next one is delivered, and that has happened in several districts. Check availability before you buy the site, not after, and get the position in writing from the authority.

Where no capacity exists, the alternatives are delivering bespoke greenspace, which needs land you control within a sensible distance, or waiting. Neither is attractive, which is why capacity checks belong in site due diligence alongside the flood and highway searches. A Green Infrastructure Plan showing how on-site open space connects to the strategic provision helps, though it does not substitute for the SANG itself.

Evidence the competent authority needs

The authority writes the appropriate assessment, but the applicant supplies the material. Provide a plan showing the distance from the site to the protected site boundary measured accurately, the net increase in dwellings and the resulting population using the strategy's occupancy figures, the SANG solution with its capacity confirmation or the bespoke SANG design and management plan, the access management contribution calculation, and the draft heads of terms.

Add a Preliminary Ecological Appraisal covering the site itself, because the habitats question is separate from the biodiversity net gain and protected species work and the authority will want all three to agree. Where the site adjoins land notified for its own features, consent inside an SSSI boundary is a further and distinct requirement, and many heathland SPAs are underpinned by SSSI notification.

An Open Space Assessment is worth preparing alongside, because policy-compliant on-site open space and SANG provision are different requirements that authorities sometimes conflate. Do not let a scheme lose amenity space by presenting the SANG as though it satisfies both.

One caveat on timing. Ecological consultants are heavily booked in these areas, and bespoke SANG design involves land assembly, so start six months before you want to submit.

PlanScope drafts the Preliminary Ecological Appraisal, Biodiversity Net Gain Assessment and supporting statements around applications like these, structured to UK planning policy, with the facts it cannot verify flagged for a licensed ecologist. Enter your postcode on PlanScope to see which reports your site is likely to need.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. Ecological survey work and habitats assessment require a suitably licensed and competent ecologist. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.