Preliminary Ecological Appraisal (PEA) for Planning in West Sussex
A preliminary ecological appraisal is often the first ecology document a West Sussex council asks for. This page explains what it is, when it is asked for, what it covers, and what can follow. We are a referral service for independent ecologists, not an ecology firm.
What a preliminary ecological appraisal is
A preliminary ecological appraisal (PEA) is an early assessment of a site's ecology by an ecologist. Council lists describe it as setting the ecological baseline and informing whether further surveys are needed. Many West Sussex councils ask for one with an application.
Arun asks for a PEA, or similar, to inform the site's ecological baseline, including a desktop data search of the Sussex Biodiversity Records Centre, with the results used to decide on additional surveys. Chichester and Crawley also ask for a data search.
When councils ask for a PEA
Councils such as Arun, Chichester, Horsham and Worthing ask for a PEA where development could affect protected species or habitats, such as roof works, conversions, demolition, tree or hedgerow loss, or sites near ponds. Others ask for a fuller report. Check your council's list.
- Worthing: a PEA where development is within or close to ecologically important areas or could affect protected or notable species, with examples including works to or demolition of a building or roofs, removal of trees, scrub or hedgerows, and sites within 500m of a pond.
- Chichester: a PEA with a data search and a Protected Species Survey Checklist for conversions, demolition where bats may be present, and sites within or within 400m of local wildlife sites or SSSIs.
- Horsham: a biodiversity survey report or PEA where development is likely to affect habitats or species.
The home page table covers every authority, including those asking for a fuller ecological impact assessment.
What a PEA covers
Chichester's list says the ecological report should record which protected species are present, map habitat on and around the site, state any limits on the survey, identify further surveys, propose mitigation where needed and provide biodiversity enhancements. Your ecologist sets the scope.
Arun adds that a PEA informs the baseline and that results from the records centre search guide the need for further surveys for protected species or sites. Worthing says some surveys are seasonal, and that a species-specific survey follows where protected species are identified.
Possible outcomes of a PEA
Outcomes can include no further surveys, further species surveys such as bat emergence surveys, or habitat information for biodiversity net gain. Which applies depends on the site and the council, and the ecologist's report sets out what is recommended for your site.
- No further surveys. Some councils accept a PEA alone: Mid Sussex where no further surveys are needed and significant impacts can be ruled out, Crawley where negligible potential for protected species is shown.
- Further surveys. Chichester's list gives a bat emergence survey as an example and says the secondary surveys must be submitted with the PEA. See the bat survey page for visits and season.
- Biodiversity net gain. Where BNG applies, Horsham's list asks for a habitat survey report with map and photos evidencing the baseline habitat assessment. Check the BNG exemptions summary first.
How long a PEA stays valid
There is no fixed period. CIEEM's advice note says a report under 12 months old is likely to be valid in most cases, and one over 3 years old is unlikely to be valid. In between, it depends. Councils may apply their own limits, so check with yours.
For 12 to 18 months, CIEEM says likely valid with exceptions such as mobile species or new features. For 18 months to 3 years, a professional ecologist needs to visit the site and provide a validity statement. Chichester's 2018 guidance says surveys should be up to date.
What a PEA costs
One UK firm publishes a preliminary ecological appraisal price from £450, with VAT not stated. No Sussex-area firm we checked publishes prices, so local costs are by quote. The cost page sets out the published figures, where each firm is based and when we looked.
Compare the published ecology survey prices, then request quotes for your site.
Frequently asked questions
Short answers on whether a householder extension needs a PEA, how a PEA differs from an ecological impact assessment, and whether an existing appraisal can be reused. They summarise the sources below and are not planning advice. Councils may apply their own rules.
Do I need a PEA for a householder extension?
It depends on the council and the site. Arun's householder list asks for a survey for modification, conversion or demolition of buildings, especially roof voids, where protected species are likely, and for buildings near open land or water. Chichester's 2018 guidance mentions householder applications involving demolition or conversion of agricultural or derelict buildings in a rural setting. Check your council's list or ask an ecologist.
Is a PEA the same as an ecological impact assessment?
Not always. Mid Sussex says a PEA alone is enough only if no further surveys are needed and significant impacts can be ruled out. Crawley accepts a PEA only if negligible potential for protected species is shown, and otherwise asks for a full ecological impact assessment. Your council's list says which it expects.
Can I use a PEA I already have?
Possibly. CIEEM's advice note says a report under 12 months old is likely to be valid in most cases, 12 to 18 months likely valid with exceptions, and 18 months to 3 years needs an ecologist's site visit and validity statement. Chichester's 2018 guidance says surveys should be up to date, ideally from the most recent survey season. Councils may apply their own limits.
Sources and dates
Council wording comes from each council's own validation document, and report validity from CIEEM's advice note. The one price quoted is from a UK firm's website. All were accessed on the dates shown; check current versions before relying on them.
- Arun District Council, Planning application validation requirements (effective 17 October 2024), accessed 9 November 2026.
- Chichester District Council, Local Validation List, November 2023 (Word document linked from the council's apply page), accessed 9 November 2026.
- Chichester District Council, Guidance on Ecological Surveys and Planning Applications (March 2018), accessed 9 November 2026.
- Horsham District Council, Development Management Local Information Requirements for Validation (no date shown), accessed 9 November 2026.
- Adur & Worthing Councils, Worthing planning application validation requirements (effective 1 April 2026), accessed 8 November 2026.
- Crawley Borough Council, National and local list of validation requirements (file dated March 2025), accessed 8 November 2026.
- Mid Sussex District Council, Validation Criteria (Local List) (council page last updated 15 September 2026), accessed 8 November 2026.
- CIEEM, Advice Note on the Lifespan of Ecological Reports and Surveys (April 2019), accessed 8 November 2026.
- Elton Ecology, Preliminary ecological appraisal (no date shown), accessed 8 November 2026.