Each year, more than 200 motorists are killed and thousands more are injured in animal-vehicle collisions, according to The Wildlife Society. Over the centuries, habitat lost to wildlife has resulted not only from highway construction but also from timber harvesting, agricultural conversion, urban and residential development, and other factors. Loss of habitat is permanent and severe. For example, the federally threatened grizzly bear is now confined to less than 2 percent of its former range south of Canada, and only two robust populations remain of the rare lynx that once prowled forested areas from Maine to Oregon. The list goes on.
Few species use all the patches of a landscape.
Their survival depends on being able to move from one patch to another. Smaller populations are less stable and, over time, face extinction from predators or natural causes. They may also be more susceptible to inbreeding and to genetic defects. Habitat fragmentation threatens all wildlife species that have to cross roads to meet their biological needs. An uphill climb for fish Impacts on fish populations are less obvious.