This service has a wide range of other names, such as ‘Extended Phase-1 Survey’ or ‘Ecological Appraisal’, we’ve even had requests for ‘Endangered species surveys’. It is typically the first phase of a more detailed baseline study, but for a small project on a simple site, it can provide sufficient information as is to inform a planning submission. At ESL we consider this assessment to include three stages:

Our preliminary desk studies may include, as relevant to the project:

  • identifying nearby sites of biodiversity importance in a local, county, national or international context;
  • sourcing and collating existing records of rare, scarce, protected and other valued species on or close to the site;
  • checking OS maps and aerial photographs of the site and locality, to identify waterbodies and other significant habitats close to, but not necessarily visible from, the site, and to consider its interconnectivity with such habitats;
  • examining geological and/or soil maps to understand the plant communities likely to be native to the area;
  • examining historical maps to identify factors which may have influenced the development of existing communities; and
  • consulting national and local atlases, floras, avifaunas, local bird or natural history reports, and the county Biodiversity Action Plan or audit.

Our walk-over surveys, carried out by one or more experienced ecologists, will include the following:

  • identification and mapping of habitats, both on the site and within a buffer area around it;
  • characterisation of plant communities by identifying the dominant, typical and other significant species;
  • assessing all hedges against the criteria for Importance for Wildlife and Landscape in the Hedgerow Regulations;
  • assessing all waterbodies and surrounding land as habitat for amphibians, specifically great crested newts, including scoring to obtain a Habitat Suitability Index;
  • assessing all habitats for their suitability for use by reptiles, and undertaking refuge searches and ‘direct observation’ transects if the survey falls within the species’ active period;
  • assessing all trees and buildings for features suitable for use by roosting bats, and the whole site, including its connectivity within the landscape, as potential bat foraging habitat;
  • assessing all ponds, streams and ditches as habitat for water voles, and searching for indications of presence such as burrows, paths, latrines and feeding signs;
  • searching the site and a buffer of adjacent land for badger setts, paths, prints, dungpits or latrines and feeding signs, and assessing the probable level of use of the site in this context;
  • recording all birds seen or heard and noting their activity, and assessing the site for habitats used by breeding Schedule 1 (specially protected) bird species; and
  • listing all other species found on the site.

Before the walkover, the project manager or field team leader will have carried out a preliminary risk assessment. This will be updated by the team on arrival, to identify specific risks and ensure that mitigation measures are in place to deal with them.

Our report will always be directly relevant to your project. In addition to describing the methods used and the results obtained it is likely to:

  • assess the biodiversity importance of the habitats, communities and species present;
  • identify potential constraints to development, and the level of mitigation likely to be required;
  • make suggestions for habitat creation or other enhancements to provide biodiversity gain; or
  • provide recommendations, and costs, for any more detailed or specialist surveys necessary to give a full ecological baseline.


All our in-house ecologists are trained to carry out such assessments, and at least one member of every field team visiting any site will have the necessary Natural England survey licences for any species likely to be found.

Why carry out Ecological Site Assessments

This type of study is likely to be required on every site for which planning permission is to be sought, with the level of detail necessary depending on the size of the application and the complexity of the site, but may also be carried out for other reasons. Typical reasons for requesting this type of study may include:

  • pre-purchase, in order to identify potential constraints to development;
  • as a stand-alone report to accompany a small application for which an EIA is not required;
  • as part of a scoping survey, together with discussions with statutory and other consultees;
  • as the first stage of the baseline investigations for an EIA;
  • to update existing information on a ‘banked’ site;
  • to assist a Local Planning Authority with the identification/selection of sites for particular
  • purposes in the LDF process; and
  • to provide the current baseline for production of a management plan for a nature reserve.

In each case, senior staff will advise on how the basic survey would be adjusted to provide exactly the type and level of information required for the project.

Timing of surveys

This level of assessment can be carried out at any time of year, but more detailed surveys may be required in the relevant season as specified by Best Practice guidance. Senior staff will always explain any seasonal concerns in advance, and will advise on survey timing for particular projects and habitats.