Adders on Clay

There are one or two places on both the Wealden clay and London clay where adders have been reported in the past. However, these sites generally have sandy outcrops and are on the edge of the clay. The occurrence of adders on clay in Kent has always struck me as unusual, perhaps dispersing individuals. Wholly clay sites are more typically associated with grass snake in Kent.

Following Tony's observations reported in another thread, I am interested in the types of habitat where adder are recorded elsewhere, especially those on clay. If animals are recorded from clay are there features of the landscape that are important (e.g. steep south facing slopes etc).

I have attached a quick distribution map (without the dots) that illustrates what we believe the historical range of the adder was in Kent. Note that this map was prepared using available data and is subject to change. Also, since geology has been used to define some of the outer edges of the range (where records are few/nonexistent), the map is a little self serving. Most recent records are from the chalk/upper greensand boundary in the west and chalk in the east.




Edited by calumma

Jon: roadside verges can offer excellent habitat for reptiles. Indeed roads can be viewed as a two-headed beast. Their creation results in habitat loss with resulting fragmentation of populations, while at the same time roadside verges can offer excellent habitat and act as important dispersal corridors through otherwise inhospitable habitat (e.g. arable). Railway lines can act in a similar manner (although they are probably less important as dispersal barriers).

I would imagine that during construction of roads in clay areas there is significant import of ballast?

Lee