Habitat fragmentation and transport infrastructure
Transport corridors, such as roads and railroads, are a major cause of habitat fragmentation. Transport corridors not only cause the loss of natural habitats due to their demand for space, but also affect the quality of adjacent habitats due to, for example, pollutants, noise, hydrological impacts or light pollution. Furthermore, transport corridors hinder movements of ground-dwelling animals through the landscape, which may result in the increased isolation of wildlife populations. Last but not least, transport corridors can increase unnatural wildlife mortality due to collisions with vehicles. All these impacts can increase the risk of the (local) extinction of wildlife species, especially those that are already vulnerable or endangered.
Roads can bisect important wildlife habitats and reduce animal movements between habitats on opposite sides of the road. As a result, relatively small groups of animals can become isolated, reducing their viability and likely survival. For some species the physical features of the transportation corridor can be an absolute barrier. Other species may avoid the road corridor and associated disturbance altogether.