Nature features

Little could I have realised growing up around the mountains of Cape Town, with large populations of puff adders and Cape cobras, that I would eventually study their smaller cousins up here in these northerly latitudes around the forests of North Yorkshire.

Damian Smith

However, being a “muddy boots” ecologist, what better project would have me walking through plantations in the early mornings of spring and early summer studying the favoured habitats of adders (Vipera berus)?

The project centres on the way adders relate to their environment in coniferous plantations, an interesting and fascinating subject from various view points. Adders are ectothermic (ecto=outside, therm=heat) and heat their bodies from the sun. We, and other mammals, are endothermic (endo=inside) so mammals need to eat a lot more to keep our bodies warm.

Male adder or vipera berus

These evolutionary adaptations mean that it costs us mammals a lot of energy to keep our bodies functioning, whereas reptiles such as adders need much less food and therefore expend much less energy foraging and feeding.

The coniferous plantations owned by the Forestry Commission are in a continuous and dynamic state of change and flux. Closed canopy, older plantations allow no sunlight to reach the forest floor – not making ideal basking sites for adders.

These high forests are felled leaving a completely open habitat which is good for basking requirements but leaves adders exposed to soaring raptors and other birds of prey. Plus, the felled areas have no great seed banks therefore not attracting rodents, which adders feed on.

Damian gets up close and personal!

Young plantations provide cover with low conifers, semi-natural places for hibernation like old wood piles and lots of heather; leaving open spaces for basking, sufficient cover for protection from birds of prey and a healthy seed bank for rodents to keep the adders’ food source abundant. The current study has results which are consistent with these theories and most adders were found in the young plantations.

My colleagues at the Centre for Environment and Marine Sciences in Scarborough, part of the University of Hull, are taking this research further to ask questions about what will happen when the young plantations grow and the canopy closes. The habitat becomes unsuitable for basking adders and they have to move, but where to? Is the next area young, felled or closed? The Forestry Commission is already great at maintaining healthy bio-diversity throughout the forests and we hope to be able to add to keeping a healthy, diverse environment.

Damian Smith