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Preliminary Ecological Appraisal

The starting point for almost every planning ecology project. A PEA combines a desk study with a walkover survey to assess what's on your site, flag protected-species risks and identify the further surveys you'll need before your application can be validated.

Survey seasonYear-round
Report turnaround7–10 working days
StandardBS 42020:2013
Also known asExtended Phase 1

Overview

A Preliminary Ecological Appraisal is the foundation of any planning ecology submission in England and Wales. It tells you — and the local planning authority — what habitats are present on your site, whether protected species could be affected, and what further survey work is needed before a decision can be made.

The appraisal has two parts. First, a desk study drawing on biological records, aerial photography, designated-site data and planning history within an appropriate radius of the site. Second, an extended Phase 1 habitat survey — a systematic walkover by a suitably qualified ecologist recording habitat types, boundary features, buildings, waterbodies and any field signs of protected or notable species.

The output is a standalone report that classifies habitats, maps ecological constraints and sets out clear recommendations. If no further surveys are needed, the PEA alone may be sufficient to support your planning application. If follow-up work is required — bat surveys, newt eDNA, reptile presence/absence — the PEA tells you exactly what, when and why.

When you need this

  • You're submitting a planning application and the LPA requires ecological information at validation
  • Demolishing, converting or extending buildings that could support roosting bats or nesting birds
  • Developing land with scrub, grassland, woodland, hedgerows or waterbodies
  • Changing the use of agricultural land or brownfield sites
  • Removing or managing trees, particularly mature specimens with bat-roost potential

Our approach

  1. 01
    Desk study

    We search biological records, designated-site databases, aerial imagery and planning history to build a picture of known ecological interest within and around your site.

  2. 02
    Extended Phase 1 walkover

    A qualified ecologist visits the site to classify habitats, map features, record field signs and assess the potential for protected species. Buildings, trees and waterbodies are individually assessed.

  3. 03
    Constraint mapping

    Desk study and field data are combined into a constraints map showing ecological sensitivities, designated sites, habitat connectivity and any features requiring further survey.

  4. 04
    Reporting

    A clear, planning-ready report is produced to BS 42020 standard, with habitat maps, species assessments, survey recommendations and indicative timelines for any follow-up work.

Frequently asked questions

01Can a PEA be done in winter?+
Yes. PEAs can be carried out year-round. A winter survey may miss some botanical indicators, but it will still correctly classify habitats and assess protected-species potential. If seasonal follow-up surveys are needed, the PEA will flag the earliest available window.
02Is a PEA the same as a Phase 1 habitat survey?+
They're closely related. A Phase 1 habitat survey maps and classifies habitat types. A PEA extends this by also assessing protected-species potential and making recommendations for further survey. Most LPAs now expect a PEA rather than a standalone Phase 1.
03Will my planning application be rejected without a PEA?+
Most LPAs will not validate a planning application on a site with ecological potential unless an appropriate ecological assessment has been submitted. Submitting without one risks delays, requests for further information, or outright refusal.
04What area does the desk study cover?+
Typically a 1 km radius for protected species records and a 2 km radius for designated sites, though this varies depending on the species and features involved. Bat records may be searched over a wider area due to the distances bats travel between roosts and foraging habitat.
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