Genetic discontinuities in roe deer (Capreolus capreolus) coincide with fenced transportation infrastructure

Linear landscape elements may act as barriers to the movement of wildlife, inducing genetic sub-structure because barriers impair gene flow. This effect often occurs in response to transportation infrastructure such as freeways, requiring expensive measures, such as overpasses, to re-establish connectivity among separated populations. Here, we present a landscape genetic study using a spatial overlay of landscape elements and genetic clustering based on nuclear microsatellites in roe deer. Our results show that fenced freeways appeared as the main obstacles to gene flow in roe deer within a nationally important wildlife corridor in Switzerland. On the other hand, a wide river only showed a weak barrier effect, whereas a highly frequented but unfenced railway track had no detectable effect on gene flow. Landscape genetic overlays proved helpful in the communication with practical environmental management, as they are intuitively appealing. Furthermore, the chosen approach pointed to the need for setting priorities for building wildlife passages as a connectivity measure in the study landscape and sets the reference line for testing the effectiveness of the measures taken.