Practical techniques: Reptiles
England, Scotland and Wales (Norther Ireland and Ireland – common lizard only)
Four of the six British species of reptile are commonly encountered on development sites in England Scotland and Wales: adder (Vipera berus), grass snake (Natrix natrix), common lizard (Lacerta zootoca) and slow worm (Anguis fragilis). The other two species, smooth snake (Coronella austriaca) and sand lizard (Lacerta agilis), have specialised habitat requirements and are very rare, with many populations lying within protected sites and so are not considered further. The only reptile native to Northern Ireland and Ireland is the common lizard.
Protection and its implications
In England, Scotland and Wales, grass snake, common lizard, slow worm and adder are all protected by the Wildlife and Countryside Act 1981 (as amended) from intentional killing, injury and selling. Mitigation for these species is, however, not subject to the European Protect Species licensing process. Common lizard receives similar protection in Ireland.
Reptiles are priority species in England, Wales, Scotland and Northern Ireland. Government policy is that local planning authorities should consider reptiles when determining planning applications. In common with most protected species, the presence of reptiles can lead to planning permission being refused unless the applicant can clearly demonstrate that the species will be adequately protected during the development process, and adequate alternative habitat is provided to sustain at least the existing population. Consideration of priority species would also be expected in the UK as part of the legal Biodiversity Duty.
The planning authority may impose a planning condition or obligation for the provision of reptile mitigation. Even when they do not, and it is known that reptiles are present on the site, it is prudent to prepare a method statement describing the proposed reptile mitigation and agree this with either the relevant local authority ecologist or the local statutory conservation officer.
The habitat of common reptiles is not specifically protected in the same way as fully protected species, such as great crested newts, and there is no licensing system to compel the provision of replacement habitats to compensate for losses associated with a development. However, an obligation to replace reptile habitat may still come through the planning system and animals captured from a development site have to be released somewhere. Releasing reptiles into unsuitable habitat could constitute an offence under the Animal Welfare Act 2006 (UK) or the Animal Health and Welfare Act 2013 (Ireland).
Reptile mitigation is seasonally constrained, relatively time consuming and may encompass a lengthy lead-in period. It is therefore advisable to have any reptile mitigation scheduled into the construction programme at the earliest opportunity.
Protecting individual reptiles
Ideally, key features within the development site which provide habitat for reptiles should be retained. Such features include ponds (used by grass snakes), coarse grassland and open scrub. This will not only provide reptiles with habitat following the development, but should also limit the numbers that need to be captured and may reduce the time taken to remove the reptiles from the works area.
If only very small areas of suitable reptile habitat will be affected by the development, it may be possible to progressively make the habitat unsuitable and encourage the reptiles to move out of the works area of their own accord. This can be achieved by cutting the vegetation in stages down to ground level in the season when reptiles are active, working towards an adjoining area of suitable reptile habitat. Provided that vegetation is kept short, the reptiles should not return. However, this could be ensured by the erection of reptile proof fencing around the works area. This process may only take a few days to complete.
If larger areas of suitable habitat are affected, then it is likely that a programme of capture and removal will be required. Typically, reptile-proof fencing is erected around the perimeter of the works area and squares of roofing felt are used as artificial refugia to attract reptiles. Daily checks of the refugia are then made and any reptiles found using them are caught and removed from the works area. The process may be hastened by modifying the habitat as described above and concentrating the reptiles into ‘islands’ of suitable habitat to facilitate capture. The time of day as well as the season in which this work is undertaken will influence capture rates. Current guidelines indicate that the trapping programme should last for a minimum of between 2 months and 2 years depending on the species and the size of the population.
Following either habitat manipulation or a programme of capture and removal, it is common practice to undertake a destructive search. This involves carefully and systematically excavating the top layers of soil and searching for reptiles as the work progresses. This approach carries a risk of killing and injuring reptiles and should only be carried out when reasonably confident that at least the majority of reptiles have been removed or there are otherwise very few reptiles present.
Maintaining reptile habitat
As with great crested newts, individual reptiles captured during a trapping programme should either be accommodated within an on-site receptor area or translocated off-site. Finding an appropriate receptor site is often the biggest hurdle to overcome when embarking on a translocation exercise as there are a number of criteria which should be met in order for a site to be suitable. These criteria usually include the presence of suitable habitat and the absence of an existing reptile population. This is an unlikely scenario in some parts of the country. Therefore, a receptor site with presently unsuitable habitat may be needed, so that it can be made suitable for reptiles before any trapping can begin. Ideally, the receptor site would be connected with other areas of suitable reptile habitat.
Some examples of habitat enhancements and/or creation that are suitable for reptiles include:
- Creating mixed patchy vegetation with areas of bare ground, coarse grasses, scattered and dense scrub, either by cutting back existing vegetation or relaxation of existing management of grassland and supplementary planting of native shrubs
- Creating free-draining, south-facing slopes with piles of rocks exposed to the sun for basking sites
- Creating new ponds as breeding habitat for frogs – the favoured prey of grass snakes
- Creating piles of rotting vegetation which can be used as egg laying sites by grass snakes
- Creating artificial hibernacula and refugia from a combination of logs, stone and turf
As always, care should be taken not to damage other habitats of ecological value when new features are created for reptiles. It is perhaps less likely that post-development management of common reptile habitats will be required by the local planning authority than for fully protected species. However, it is good practice to manage newly created or enhanced reptile habitat to ensure that it remains suitable for reptiles in years to come. Habitat management is likely to involve the occasional cutting back of vegetation to maintain mosaics of varied vegetation and open areas for basking.
Timing of works
Work with reptiles can be undertaken from spring through to late autumn, although artificial refugia are much less effective at attracting reptiles when temperatures are high, as may occur in high summer (July and August) and so this would need to be allowed for in any programme of capture and removal. Habitat creation and enhancements can potentially be undertaken at any time of the year.
English Nature (2004) Reptiles: guidelines for developers. English Nature, Peterborough.
Langton, T. (1989) Snakes and lizards. Whittet Books, London.
Edgar, P., Foster, J. and Baker, J. (2010). Reptile Management Handbook. Amphibian and Reptile Conservation, Bournemouth.
Herpetofauna Groups of Britain & Ireland (HGBI). 1998. Evaluating Local Mitigation/translocation Programmes: Maintaining Best Practice and Lawful Standards. HGBI advisory notes for Amphibian and Reptile Groups (ARGs).
Natural England (2015) Reptile surveys and mitigation for development projects. https://www.gov.uk/guidance/reptiles-protection-surveys-and-licences