Ecology for planning

Ecological surveys for planning applications

If your planning application involves land, trees, hedgerows, ponds or older buildings, your council will usually want ecology evidence: a preliminary ecological appraisal, and in England a biodiversity net gain assessment. Here's what each survey involves, when it can be done and what it typically costs. We can also introduce you to one vetted ecologist who covers your site.

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Beatrice Vasey is a horticulturist, not an ecological consultancy. We introduce you to one vetted ecologist and are paid a referral fee by that business.

Which survey do you need?

Most sites start with a preliminary ecological appraisal. It decides whether you also need species surveys, and in England it usually feeds straight into the biodiversity net gain assessment.

Survey	What it involves	When it can be done	Typical cost
Preliminary ecological appraisal (PEA)	A rapid assessment of the ecological features on a site: a desk study of local wildlife records plus a walkover habitat survey. It maps the habitats, flags protected species that could be present and says which further surveys, if any, are needed.	Any time of year; the habitat survey is most reliable from April to September	About £500 (small sites) to £2,000 (large sites), plus VAT
Biodiversity net gain assessment (England)	A habitat condition survey and a statutory biodiversity metric calculation, showing the site's biodiversity value before and after development and how the 10% gain will be met, on site or off site.	Best April to September, when habitats can be assessed properly	From about £490 plus VAT on small sites
Habitat management and monitoring plan (England)	Sets out how the habitats created or enhanced for biodiversity net gain will be managed and monitored. Significant on-site gains and all off-site gains are secured for at least 30 years.	A draft with the planning application; the full plan with the biodiversity gain plan	From about £495 on small sites
Ecological impact assessment (EcIA)	A full report on how the development will affect important habitats and species, and the mitigation, compensation and enhancement needed. It usually follows a PEA and any species surveys.	Once the surveys it relies on are complete	From about £750 for a straightforward site
Protected species surveys	Targeted surveys for species the PEA flags, such as bats, great crested newts, reptiles, badgers or nesting birds. Each has its own season.	Depends on the species (see the seasons table)	Quoted per species and site; great crested newt eDNA is about £250 to £500 per pond

Typical prices from published consultancy cost guides (see sources below). Your ecologist quotes for your site.

Biodiversity rules in England, Scotland and Wales

Each nation handles biodiversity in planning differently, so the evidence your council expects depends on where the site is.

England

Mandatory biodiversity net gain

Most planning applications must deliver at least a 10% biodiversity net gain, measured with the statutory biodiversity metric. Householder applications, very small habitat impacts and, since 6 August 2026, sites of 0.2 hectares or less are exempt, unless a priority habitat is affected.

Scotland

Biodiversity enhancement under NPF4

Policy 3 of National Planning Framework 4 requires all development to contribute to enhancing biodiversity, with significant enhancements on national, major and EIA development. There is no percentage target and no mandatory metric yet; a Scottish planning biodiversity metric is in development.

Wales

Net benefit for biodiversity

Planning Policy Wales requires development to deliver a net benefit for biodiversity using a step-wise approach, shown in a green infrastructure statement with every application. Wales does not use a biodiversity metric.

Protected species survey seasons

If the appraisal finds a site could support protected species, follow-up surveys have to fall in that species' season. Missing a window can delay an application by months.

Species	Survey season
Bats	May to September for emergence surveys, with some visits needed May to August
Great crested newts	Mid-April to end of June for eDNA pond sampling; mid-March to mid-June for population surveys
Reptiles	April to September; April, May and September are best
Nesting birds	March to August is the main nesting season
Badgers	Year-round; February to April is the optimum time
Otters	Any time of year, avoiding the days after heavy rain
Water voles	March to October
Hazel dormice	April to November, using nest tubes checked monthly

How long survey results stay valid

Councils want recent evidence. CIEEM's advice on the lifespan of ecological reports gives a rough guide:

Under 12 months old: likely to be valid in most cases.
12 to 18 months old: likely to be valid, though surveys for mobile species such as bats or badgers may need updating.
18 months to 3 years old: an ecologist will need to visit the site to check it, and some surveys may need repeating.
Over 3 years old: unlikely to still be valid; surveys will usually need doing again.

How the introduction works

Tell us about the site and the planning application, using the form below.
We email you the name of one vetted ecologist who covers your site, then pass your enquiry to them. Your details go to one business only.
They quote you directly and carry out the surveys.

We are paid a referral fee by the ecologist. If you'd only like advice, leave the consent box unticked and Beatrice will reply herself.

Ecological surveys by city

Each city page covers the local council, the biodiversity rules that apply there, the local nature recovery strategy in England, and where ecologists get local wildlife records.

Questions about ecological surveys

Does every planning application need an ecological survey?

No. Councils ask for one when a site could affect protected species or valuable habitats: undeveloped land, mature trees, hedgerows, ponds, rivers, or older buildings. A preliminary ecological appraisal is the usual first step, and it tells you whether anything more is needed.

Does a house extension need biodiversity net gain?

Not in England: householder applications are exempt from mandatory biodiversity net gain. Protected species law still applies, so an extension that affects a roof space or a pond may still need a bat or newt survey.

Is a small site exempt from biodiversity net gain?

In England, since 6 August 2026, applications for sites of 0.2 hectares or less (measured on the red line boundary, hardstanding included) are exempt, unless they affect a priority habitat. Self-build homes applied for on or after that date are no longer exempt. Sites just above the threshold can often use the Small Sites Metric, which doesn't have to be completed by an ecologist.

What is great crested newt district level licensing?

An alternative to standard newt licensing, run by Natural England or NatureSpace in some council areas in England. The developer pays a conservation payment that funds new ponds, so newt surveys aren't needed for the application. Each city page says whether its area is covered.

Can ecological surveys be done in winter?

The desk study and an initial site visit can, but habitats are hard to assess outside the growing season and most protected species surveys only run in spring and summer. Booking early in the year avoids a wait of up to twelve months.

Is Beatrice Vasey an ecologist?

No. Beatrice is a horticulturist and botanical surveyor. For ecological surveys we introduce you to one vetted ecologist who covers your site, and we are paid a referral fee by that business.

Get an ecological survey quote

Tell us where the site is and what's planned. Beatrice reads every enquiry.

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