Reptile Presence/Absence Surveys are an assessment of whether reptiles are present on site and, if so, which species. This is usually recommended as a further survey after a Preliminary Ecological Assessment, where habitats suited to support reptiles have been identified on site. Reptile Presence/Absence Surveys are needed to inform the requirements for avoidance, mitigation, compensation, and enhancements for reptiles, usually where reptile habitat has been previously identified, as part of the planning process. The aim of Reptile Presence/Absence Surveys is to gather as much information about the number and species of reptiles using the site and surrounding area as possible, so that the potential impacts of the proposed development on reptiles can be assessed. This is achieved through a three-part process: a desk study, field surveys, and an evaluation/impact assessment, all of which is usually presented in a report.
A desk study involves obtaining details of the landscape surrounding the site, so that the ecologist can assess both the likelihood of reptiles being present on site and the potential impacts of the develop on ecologically important sites and habitats for reptiles in the surrounding area. This study includes identifying Priority Habitats and Statutory Designated Sites within one kilometre of the site.
Field surveys involve an ecologist visiting the site to gain information on the presence or absence of reptiles within the existing habitats. This involves at least eight visits to site, the first comprising the deployment of at least fifty reptile refugia (bitumen roofing felt squares measuring 0.5x0.5m) within habitats where reptiles are likely to be present on site (in accordance with best practice guidance; Froglife, 1999). For large sites with extensive areas of habitats suited to supporting reptiles, it may be necessary to deploy over fifty reptile refugia. Refugia must be left in place for a period of at least ten days before the other seven (or more) field surveys can commence. Subsequent visits can be made on consecutive days (schedule allowing). During each subsequent visit, the ecologist inspects under the refugia for reptiles warming and sheltering under the square, and signs of their presence on site, such as reptile slough. This is done by lifting up the refugia in an appropriate manner, and replacing it once observation has finished. Care is also taken to carry out direct observation surveys for reptiles basking in the open, away from refugia. Where reptiles (and signs thereof) are found, species, gender, and life-stage are recorded where possible. It is worth noting that field surveys are only able to be conducted in April, May, and September, and between 8.30am and 11am, or 4pm and 6:30pm. Air temperature on each visit must be between 9°C and 18°C, and periods of moderate to high winds will be avoided. Permission from the landowner and a full risk assessment are required prior to field surveys.
With the information from the desk study and the field surveys, the ecologist can then carry out the evaluation assessment for the presence/absence of reptiles on site and whether the proposed development will have an impact on reptiles. Here, the ecologist will calculate the peak count of each species of reptile found on site which, in turn, enables the ecologist to assess the estimated population size for those reptile species. For adders, grass snakes, common lizards and slow worms, the population scores are as follows: peak count <5 individuals indicates a low population; peak count of 5-10 individuals indicates a good population; and >10 individuals indicates an exceptional population (Froglife, 1999). The assessment made is presented in a report and includes an evaluation of the potential impacts of development and details the avoidance/mitigation/compensation/enhancement measures for reptiles that should be implemented (if any). The reports we write are in accordance with the up-to-date CIEEM guidelines for ecological report writing. The ecological reports are valid for 12 months so must be submitted to inform a planning application within a year of the report being issued. An updated survey may be required if the report is not submitted in time.
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