Bat Survey Guidelines

Bat Survey Guidelines

The second edition of Bat Surveys: Good Practice Guidelines has recently been published by the Bat Conservation Trust, and this builds upon the guidance set out in the first edition and draws upon a range of new information.  It is likely that this document will quickly become established as the new standard for bat survey work, and for this reason it is important that developers and others understand the implications for their projects.  Some of the key points are summarised below, and further advice is available from BSG Ecology.

It is important to note that this document only sets out ‘guidance’ and consequently there is scope to deviate from the recommended survey work if this can be justified.  This approach is a fundamental part of the guidance, which states: “The guidance should be interpreted and adapted on a case-by-case basis, according to the expert judgement of those involved”.  Despite this, it is likely that some bodies will choose to apply the guidance verbatim, as happened with the first edition, which makes early liaison with ecology stakeholders a worthwhile exercise to ensure that their interpretation of the guidance is understood.

The guidance has now been updated to include additional information on the legislative protection afforded to bats, the skills required by surveyors, and the planning and scoping of bat surveys.  This includes useful tabulated information to help with the initial screening of a site to determine if it is has low or high value for bats, or if it falls somewhere in-between. Such an assessment has a bearing on the survey effort appropriate to given situation.

Importantly the guidance introduces the concept of proportionality when defining the scope of survey work, stating that “greater survey effort should be expended at sites where high numbers of bats are likely to be present and where they are likely to be adversely affected”.  In other words, the scale and size of a development alone should not be used to decide what bat surveys are required, and the guidance and advice of experienced ecologists should be brought into play.

This latest version of the guidance includes updated advice on the minimum level of survey work that will be required for a range of development scenarios, i.e. small, medium or large sites with habitat that is of low, medium or high quality.  In the majority of cases it will be necessary to carry out multiple surveys at a site at an appropriate time of the year: data will need to be collected using personnel as well as automated (unattended) monitoring equipment.  In some situations the required scope of bat survey work has increased from that specified in the previous edition.

Whilst it is possible that lower levels of survey effort than those specified in the guidance may be acceptable in some circumstances, any decision to deviate from the guidance will need to be robustly justified.  Failure to do this will leave the results of those surveys and any subsequent conclusions open to challenge, potentially delaying the planning process.

The latest edition of the guidance now includes a chapter that provides specific advice on surveying wind farm sites.  A two-stage process is described, whereby the site is initially assessed to determine the risk posed to bats (low, medium or high).  Once this is known, the minimum scope of the baseline survey work is determined based on the site risk rather than the size of the development.  A draft version of this chapter was published in 2011, but it should be noted that the recently published guidance has evolved further since the publication of this earlier document.

The new guidance provides greater clarity about the scope of survey work required for different development scenarios, but necessarily steps back from being overly prescriptive.  It therefore places a certain amount of responsibility on the consultant bat ecologist to carefully evaluate a site, determine an appropriate scope of survey work, and to provide robust justification.  BSG Ecology has considerable experience in scoping and carrying out bat surveys, and if you would like any advice please get in touch.

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