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What is a Preliminary Ecological Appraisal?

A Preliminary Ecological Appraisal, or PEA, is the initial scoping assessment of an area of land to record the habitats present and its potential to support protected species. PEA’s are required to inform the mitigation hierarchy (avoidance, mitigation, enhancement and compensation) and requirements for further ecological surveys for protected species, as part of the planning process. The aim of a PEA is to gather as much information about the site and the surrounding area as possible, so that the potential impacts of the proposed development on designated sites for nature conservation, protected habitats and protected species can be assessed. This is achieved through a three-part process: a desk study, a field survey, and evaluation/impact assessment.


A desk study involves obtaining historical ecological records from the local biodiversity records centre, so that the ecologist can assess the likelihood of protected species being present on site and assess the potential impacts of the development on ecologically important sites and habitats in the surrounding area.


A field survey involves visiting the site to map the habitats present to provide a ‘snapshot’ of the current conditions of the site, in accordance with the up-to-date CIEEM guidelines for PEAs. Additionally, all the flora and fauna are recorded, including any signs of protected species, if present, to serve as a baseline for further survey work. Permission from the landowner and a full risk assessment are required prior to the field survey.

At aLyne Ecology Ltd., we now use the UK Habitat Classification system when conducting field surveys. This is an updated and more technical approach to classifying UK habitats. This approach is a hierarchical system designed to incorporate assessment of the condition, origin and management of each habitat on site.

With the information from the desk study and the field survey, the ecologist can then carry out an assessment of the site for its potential to support protected species and whether the proposed development will have an impact on them. This assessment is presented in a report and includes an evaluation of the potential impacts of development, the mitigation hierarchy and whether any further survey work is required. The reports we write are in accordance with the up-to-date CIEEM guidelines for ecological report writing. The results of any further surveys and final assessment are required to inform the planning application. The ecological reports are valid for 12 months so must be submitted to inform a planning application within a year of the report being issued. An updated survey may be required if the report is not submitted in time.


For example, the desk study may include records of multiple bat roosts being present close to the site, and during the site visit the ecologist has recorded a tree in a woodland that has a woodpecker hole in it, and therefore, could be used by roosting bats.

The records of bat roosts being present in the area, the presence of the suitable habitat (woodland) for bats present on site and the ecologist recording a tree in the woodland that has a potential roosting feature for bats (woodpecker hole) will lead the ecologist to assess the site has having potential to supporting bats. In this case, further survey for bats would be required, if the development is likely to result in an impact on bats. Further survey for bats is necessary because all bats and their roosts are fully protected Schedule 5 of the Wildlife & Countryside Act 1981 (as amended) and the Conservation of Habitats and Species (Amendment) (EU Exit) Regulations 2019.


Another example would be if there are ponds within 500 m of a site and the site has a pond that could potentially support great crested newts (Triturus cristatus), which are also fully protected Schedule 5 of the Wildlife & Countryside Act 1981 (as amended) and the Conservation of Habitats and Species (Amendment) (EU Exit) Regulations 2019, meaning the great crested newt and their habitats are protected.

Great crested newt surveys would be recommended by the ecologist because the pond on site could potentially be part of a network of ponds in the surrounding area that great crested newts would be using. Removing or altering the pond would therefore be classed as an offence. The surveys would involve surveying the pond on site and all the ponds within 500 m.


Further information on PEA’s and protected species surveys can be found on our website: https://www.alyneecology.co.uk/services.

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