Compensatory measures for Smooth Snakes during road construction in Sweden

In 2014 a major road was constructed in Bohuslän, western Sweden, through land used for foraging and hibernation by Smooth Snakes (Coronella austriaca), an endangered and legally protected species. Several mitigatory and compensatory measures were carried out during construction for the benefit of this species as well as other reptiles. A new 0.5-ha foraging site, approximately equivalent to the area lost to road construction, was established by clearing shrub vegetation and creating ponds. In addition, six new hibernation sites were constructed, to replace two known natural hibernation sites that were removed during road construction. Snakes were located and collected prior to the onset of the hibernation season and placed in the new hibernation sites. Snakes that were found during the careful demolition of the natural hibernation sites in late winter were also placed in the new hibernation sites. Foraging and hibernation sites will be managed for the next ten years, for example, by clearing encroaching shrubs , to maintain their suitability for Smooth Snakes and other reptiles. A two year monitoring programme has been established to evaluate the effectiveness of these measures. Preliminary results show that hibernation sites were functional, but only infrequently used by hibernating Smooth Snakes during the first two winters post-construction. Preliminary spring survey results show that numbers of Smooth Snakes located pre- and post construction were more or less equal.

mitigation, compensation, reptiles, road construction