Increase by 2.5% per annum in the adder range (number of monads occupied) and overall frequency of recording.
There is evidence of a considerable decline in adder distribution. In the period 1980 to 2005, 15,154 monads were recorded as occupied by the species. In 2006 to 2011 this fell to 9,237. This amounts to a potential decline of 39%.
The interpretation of data will take into account results from long-term monitoring in Kent that will indicate how prevailing conditions have influenced adder detectability and hence affected the potential recording rate. The baseline will be provided by records received by the Kent Reptile and Amphibian Group in 2018.