Local planning authorities have a statutory duty to review all planning applications and permitted developments regarding the potential ecological impact of a development and to ensure proposals will promote ecological enhancement. An ecological assessment is an appraisal of the likely impacts to wildlife (flora and fauna) of a development project and is undertaken by a suitably qualified professional ecologist .

An ecologist may decide to conduct a Preliminary Ecological Appraisal (PEA) to understand the potential ecological impacts that might be incurred by a proposed development. The PEA can involve a desk study and / or onsite surveys. The findings of the PEA will indicate to the ecologist whether more detailed Ecological Impact Assessment (EcIA) surveys are necessary:

  • Desk study: Also known as a background data search, a desk study involves an professional ecologist who will review the development proposal alongside maps, aerial photographs, photographs of the site and local statutory designated sites for nature conservation. The consultant will also obtain local data from a variety of sources, including Local Environmental Record Centres and local wildlife groups.
  • On-site survey: Also known as a site walkover, site assessment, constraints survey or scoping survey, this appraisal involves a visit conducted by a professional ecologist to a development site to assess the species, habitats and features present.

The PEA is used to: clarify relevant statutory obligations regarding biodiversity; identify potential ecological constraints or impacts regarding protected and priority species and habitats; determine the requirement for further EcIA surveys that will need to be submitted in a planning application; outline likely impacts and opportunities for mitigation, compensation and enhancement; consider necessary consultations with statutory bodies; and the need for consents (BS42020:para 6.1.9).

PEAs should be conducted in accordance with the CIEEM Guidance for Preliminary Ecological Appraisals (BS42020: para 6.4.1). The PEA may indicate that it is necessary to undertake further ecological surveys, in the form of an Ecological Impact Assessment (EcIA):

    Ecological Impact Assessment (EcIA) is a more detailed process of identifying, quantifying and evaluating the potential effects of a development, regarding impacts on species, habitats, and / or ecosystems for submission with a planning application. The assessment considers impacts within the development site, the surrounding locality and, where appropriate, on regional or national ecological resources. An EcIA is usually the main assessment that is submitted with a planning application, unless the planning authority agrees that a PEA report is sufficient. The results of an EcIA should also be shared with Local Environmental Records Centre.

If the development is subject to the Town & Country Planning (Environmental Impact Assessment) Regulations 2011, then a broader Environmental Impact Assessment (EIA), which includes an EcIA, will be required.

Note: Regardless of which assessment is applied, all planning applications should outline opportunities to promote wildlife gains through ecological enhancement in accordance with the National Planning Policy Framework.

Further guidance:

BS40202 Biodiversity – Code of practice for planning and development: The British Standard for Biodiversity (BS42020) provides recommendations on how to ensure a professional, consistent and scientific approach to gathering ecological information at each of the key stages of the planning and development process.

CIEEM Technical Guidance Series Guidance for Preliminary Ecological Appraisals: provides best practice guidance for those undertaking preliminary ecological appraisals, setting out the minimum standards required. It provides key steps involved in an appraisal and recommends consistency in terminology across baseline appraisals to aid developers and planning authorities.


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