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Assessing the impacts of developments

Water voles and the planning system

Planning authorities are required to take account of protected species and habitat conservation when they consider planning applications, see Scottish Planning Policy external site . Where water voles are present or likely to be present, the planning authority may require a survey to be undertaken, paid for by the developer. If water voles are likely to be affected, the planning authority may introduce planning conditions and/or agreements when determining individual applications.

Water vole surveys

There are two ways to find out whether there are water voles on site:-

  • desk-based collation of known records
  • site-based survey

Desk study 

The desk-based study should review records of water voles from sources such as Local Record Centres external site or the NBN Gateway external site .  Note that the dramatic decline in water voles means that many older records (i.e anything much older than the Year 2000) must be treated with caution as they are unlikely to reflect the present situation, especially in lowland areas.

Site survey

A field survey should be based on the presence of characteristic field signs such as burrows, feeding stations, runs, tracks, droppings and latrines. Site-specific searches, by an appropriately experienced surveyor, should involve a close examination of all waterway and pond banks up to two metres from the water's edge. The presence of signs should be recorded on a detailed map. Although they do not hibernate, water voles are not very active above ground during the winter, so surveys are best carried out between April and October. In upland areas, surveys are not recommended before May or after September, the optimum months being June-August inclusive. See the Water Vole Conservation Handbook (3rd edition) for further details of field signs and survey methods. 

Note that because of the water vole's meta-population structure, sites may not be occupied in every year. Therefore, it cannot be assumed that the presence of burrows but no other field signs indicates that a site has been permanently abandoned - if there are extant colonies nearby, such sites may easily be re-occupied. 

With the exception of those areas initially eliminated as unsuitable for water voles, the whole of the development site should be surveyed. For small sites, an extra 50m upstream and downstream of the development should be surveyed. For larger schemes affecting several 100 metres (or kilometres) of riparian habitat that result in noticeable water level fluctuations and may lead to population fragmentation and habitat loss, it would be appropriate to survey for 500m both upstream and downstream of the site.

IMPORTANT NOTE: water vole surveys in the Glasgow area

Glasgow contains some of the best water vole populations in lowland Scotland. Many of these colonies are in areas of rough (but managed), urban grasslands but with no open water anywhere nearby (see Glasgow's water voles). The water voles at these sites create extensive burrow systems, but also forage extensively above ground in a manner similar to field voles (Microtus agrestis), creating latrines, earth mounds and runs through the vegetation. On the face of it, most of these sites might easily be immediately discarded as potential water vole habitat due to the complete absence of open water and the apparently poor quality habitat. It is important therefore, that developers, planners and, in particular, ecological consultants, are aware of this unusual fossorial behaviour in the area, because many of the areas occupied are zoned for development, notably new housing. Appropriate surveys of such areas are therefore needed to inform the mitigation plans required for planning permission and in support of a licence application at each site.

Hydro-electric schemes

Guidance on water vole surveys in relation to proposals for hydro-electric development is given in Annex C of Guidance for applicants on supporting information requirements for hydropower applications. external site  This approach may be adapted for other forms of development affecting upland catchments, as appropriate.

Last updated on Monday 1st August 2016 at 14:57 PM. Click here to comment on this page