When Preliminary Ecological Appraisals (PEAs) are done late, done cheaply, or done without clear scope or proportionate judgement, things can and do go wrong.
Although PEAs are intended to be straightforward baseline surveys, the way they are commissioned and delivered can dramatically influence the overall cost, programme and complexity of a planning application. A well-managed, proportionate PEA keeps the project on track. A poorly handled one can trigger:
- unnecessary specialist surveys
- missed survey windows
- rework
- duplication of cost
- planning delays (sometimes measured in months, not days)
Below are seven real-world scenario types showing how things can escalate unnecessarily — and how a properly scoped, timely PEA avoids them.
1. Problem: The “Cheap PEA” That Triggered £5,000+ of Extra Surveys
A developer began with a low-cost PEA that flagged both bat potential and great crested newt risk. Because the ecologist took a highly precautionary view, this triggered:
- 4× bat emergence/re-entry surveys
- 4× GCN surveys
- Several months’ delay waiting for survey windows
Total ecological spend: £800 → £5,000+.
What went wrong:
Over-cautious scoping and lack of proportionate judgement turned a simple baseline job into an expensive specialist programme.
2. Problem: A Late PEA Missed the Bat Survey Window — Causing a Year-Long Delay
An architect submitted a planning application with no ecology. The LPA requested a PEA. By the time it was completed, it was too late in the season to undertake the required bat surveys.
The project had to wait until the next summer to complete the full set of surveys.
What went wrong:
The PEA was done too late in the year. Missing seasonal windows can cause an almost 12-month delay.
3. Problem: An Over-Precautionary PEA Triggered an Unnecessary EcIA
A PEA on a modest semi-natural site over-interpreted habitat value and recommended:
- Full Ecological Impact Assessment
- Multiple protected species surveys
- Additional mitigation and enhancement design
The LPA had not asked for any of this, but once included, the process snowballed.
What went wrong:
A disproportionate PEA created work that neither the client nor the LPA initially required — adding several thousand pounds and months of extra work.
4. Problem: A Weak PEA That Had to Be Done Twice
A planning application included a PEA that looked neat but:
- didn’t follow CIEEM methodology
- lacked justification
- had incomplete mapping
The LPA ecologist pushed back. The client had to commission a second PEA and some additional targeted surveys.
What went wrong:
The first PEA was not robust enough to satisfy the LPA. The client paid twice and lost 2–3 months.
5. Problem: A PEA That Triggered Bat Surveys Mid-Application
A PEA said “potential bat roosts – further surveys recommended.”
The application proceeded without completing those surveys. The LPA then invalidated the application until the surveys were done.
Specialist bat surveys (£1,500–£2,500) had to be carried out in the next available window.
What went wrong:
Once a PEA identifies a need for further surveys, most LPAs cannot progress the application until they are completed.
6. Problem: No PEA at All — Leading to Refusal and Redesign
A small development was submitted with no ecological information.
Because the site contained hedgerows, rough grassland and a nearby pond, the LPA refused the application outright due to insufficient ecological evidence.
The applicant had to:
- commission a PEA
- undertake multiple species surveys
- redesign the site layout
- resubmit and pay a second planning fee
What went wrong:
Skipping the PEA created the most expensive outcome of all — refusal, redesign and months of delay.
7. Problem: A Winter PEA That Had to Be Repeated
A developer rushed a PEA in winter. The report correctly noted that habitat and botanical indicators could not be reliably assessed at that time of year.
The LPA insisted on a spring/summer update survey, leading to two site visits, two reports and additional fees.
What went wrong:
The PEA was undertaken outside the optimal survey period without agreement on its limitations — resulting in duplicated cost.
What This Means for Your Project
Across all seven scenarios, the pattern is the same:
- Badly timed PEAs cause missed survey windows and long delays
- Over-defensive PEAs escalate small schemes into expensive multi-survey programmes
- Weak PEAs get challenged by LPAs and must be repeated
- Cheap PEAs are often the most expensive once the follow-on effects appear
- No PEA is, by far, the most costly error
The solution is simple:
A well-timed, proportionate, correctly scoped PEA delivered through the right expertise keeps costs low, avoids unnecessary specialist surveys, prevents rework, and keeps the planning process moving.