In recent decades, Switzerland has experienced extensive urbanisation. Urbanisation destroys, alters and dissects natural and semi-natural habitats, and at the same time, also creates new habitats. Transport infrastructure is a prominent component of urban land-use, and road and traffic densities are generally high in urbanised landscapes. Several studies indicate a general fragmentation effect of roads and traffic on populations of animal species, due to inaccessibility of resources, increased road mortality and subdivision of populations. Traffic infrastructure and their verges, however, often provide new habitats for plant and animal species. They are characterised by a high amount of non-native species, but are also valuable habitats for endangered species of agricultural landscapes. In addition, they act as migration corridors for non-native and native species and, in combination with urban habitats, facilitate the biological invasion of landscapes.