Baker Consultants

New water vole mitigation guidelines for development and construction

The Mammal Society has just published new water vole mitigation guidelines for development and construction projects.

Here we provide an overview of the background to the guidelines as well as the key recommendations within them. The full guideline PDF can be viewed below.

Water voles

Water voles (Arvicola amphibius) are one of the UK’s fastest declining wild mammals and listed as a species of principal importance for the conservation of biodiversity in England, Scotland and Wales. As such, they are protected under UK wildlife conservation legislation, making them of material consideration in the determining of planning applications.


New water vole mitigation guidelines

The Mammal Society’s new publication aims to promote best practice amongst ecological consultants in undertaking surveys and designing and implementing water vole mitigation measures. It also aims to enable decision makers to ensure the appropriateness of survey information provided and mitigation measures proposed.

The guidance relates to development projects and other construction activities, including those requiring other environmental permits, such as flood defence consent. It supersedes the Water Vole Conservation Handbook in all aspects relating to development.

The below flow chart shows the different elements involved in considering water voles as part of a planning application.

New water vole mitigation guidelines for development and construction | Baker Consultants

Flow chart for considering water voles as part of a planning application. From The Water Vole Mitigation Handbook


Key recommendations

  1. Licensing for displacement: Activities aimed at displacing water voles in the context of a development project require a licence and are not covered by the ‘incidental result’ defence. Different types of licence are required for England, Wales and Scotland (see the full guidelines for details). In both England and Wales, the projects must deliver a net benefit for water voles.
  2. Relocation of water voles (trapping versus displacement): Although further research is needed on the effectiveness of displacement, displacement is currently considered a potentially useful technique, particularly for small-scale works where trapping would be disproportionately expensive and could impact other animals due to individuals moving into vacant territories. As a rule, displacement is recommended where the working area is a maximum of 50m long, where works are carried out between 15th Feb and 15th April and where sufficient available alternative habitat exists. In England, displacement that meets these criteria can be conducted under a Class Licence by a registered person, whereas displacement under other circumstances requires a site-specific licence. In Scotland and Wales, a site-specific licence is always required.
  3. Appropriate timing for trapping and relocation operations: Water voles should ideally be trapped during early spring (1st March – 15th April). As a last resort, water voles can also be trapped during autumn (15th September – 30th November). Trapping should be timed to avoid periods of heavy rain or snow, fluctuating water levels and periods when overnight temperatures fall below freezing. Some seasonal variation in appropriate dates for trapping is acceptable in certain parts of the UK.
  4. Water vole surveys that support planning applications and other construction activities: There are specific suggested protocols for field surveys that will support planning applications or other construction activities. Typically, the baseline information used to inform an assessment of the effects of a development on water voles should be based on a combination of desk study, habitat assessment and field sign survey. Field sign surveys should ideally include searches for field signs undertaken over at least two separate visits, conducted at least two months apart to account for variations in habitat suitability across the season. One survey should be in the first half of the season (mid-April – June) and one in the second (July – September). However, there are some circumstances in which only a single visit is likely to be necessary (see page 15 of the guidelines).


Find out more

Contact us today to discuss any aspect of these guidelines or any upcoming projects for which you may need water vole surveys or advice

Read the full guidelines here.