Reptile surveys are often required as a planning condition when a site provides suitable habitats for reptiles. There are six species of reptile which are legally protected in the UK. These includes three species of snake: adder, smooth snake and grass snake, and three species of lizard: common lizard, sand lizard and slow worm. Of these, adders, grass snakes, common lizards and slow worms are relatively common, while smooth snakes and sand lizards are very rare, found only in localised populations in the south of the UK.
The suitability of a site for reptiles is initially assessed by a walkover survey. This is often carried out as part of a Preliminary Ecological Appraisal. If a site is deemed to provide suitable habitat for reptiles, a reptile presence/absence survey is recommended.
A reptile presence/absence survey consists of two main techniques: the use of artificial refugia and a visual search. The optimal time to survey for reptiles is in spring and autumn. Reptile surveys cannot be carried out between November and February, when reptiles are hibernating.
The use of artificial refugia consists of the placement of corrugated metal sheets and bitumastic roofing felt mats, usually 70cm x 70cm in size, on suitable locations within the site. These warm up in the sun, providing favourable conditions for reptiles. These refuges are then periodically checked for the presence of reptiles. The use of artificial refugia is particularly useful for detecting slow worms and smooth snakes, which can be difficult to detect by eye, and can also be useful in detecting grass snakes and adders, although these can also be observed in a visual search.
The visual search is particularly useful in identifying the presence of common and sand lizards, which are rarely found under artificial refugia. The visual search is usually carried out in conjunction with the use of artificial refugia, and involves a slow walkover of the site, visually searching for reptiles in locations such as sun traps, tall vegetation and ecotones. Pre-existing objects acting as refugia, such as discarded tyres and scrap are also searched.
The reptile survey is accompanied by a desk based study, whereby local record centres, reptile groups and web based sources are consulted as to any pre-existing records regarding reptile activity.
If reptiles are found to be present on a site, our ecologists are able to suggest appropriate mitigation recommendations to ensure that a proposed development has no negative impact upon reptile populations, ensuring that the required planning consent is achieved.
For more information regarding reptiles, their habitat requirements and legal status, we recommend viewing the Amphibian and Reptile Conservation Trust's website. If you have any further questions regarding reptiles and reptile surveys, please contact us.