The relationship between roads and habitat fragmentation is well documented. One study found that roads contribute more to fragmentation in forest habitats than clear cuts . Another study concluded that road fragmentation of formerly contiguous forest in eastern North America is the primary cause for the decline of forest bird species and has also significantly harmed small mammals, insects, and reptiles in the United States . After years of research, biologists agree that roads and traffic lead to habitat fragmentation, isolation and road kill, all of which combine to significantly compromise the viability of wildlife populations throughout the world.