Nigel Brooke-Smith, an Ecology MSc student at Bath Spa university, analysed Ecosulis Great Crested Newt survey (http://www.ecosulis.co.uk/page/great-crested-newt) data from 2010 and 2011. He found that there is a strong link between habitat (as measured by habitat suitability index or HSI) and the presence of newts. This link has been well established by other researchers. However he also found that different survey techniques have different success rates, the most successful being torch surveys and the least successful, egg searches. It is not always possible to do torch surveys (e.g. when the pond is cloudy) and Natural England specify the use of mixed survey methods.
The most interesting part of the research relates to the number of negative surveys that are needed to prove the absence of newts. Using Bayesian statistical techniques it can be shown that more surveys are needed for the good ponds and fewer for the less good ponds. Current Natural England guidelines specify the same number of surveys for all ponds and a change in the guidelines could result in a more effective use of ecological survey effort.
Nigel is very grateful to Ecosulis for providing their results for research. He thinks that this is something that all consultancies should do to make wider use of their survey data.