Two well-known examples exist. First, in North America, a corridor occurs in the Rocky Mountains that stretches from the Canadian boreal region, all the way through the United States, and eventually into northern Mexico. Note that this corridor is believed to be the route taken by early Native Americans 10,000 years ago who made their way to the Southwest at the end of te last Ice Age. Second, the continent of Eurasia links western Europe to China and has acted as a corridor for the dispersal of plants and animals. This corridor likely occurs because of the great land mass that Eurasia occupies and its even, latitudinally-arranged contours of climatic zones.
Corridors usually contain just one primary type of habitat.
The second method that facilitates dispersal is known as a filter , which consists of a variety of habitats so that only those organisms that can exist in them are allowed to disperse. Unlike a corridor, which has one primary habitat type, a filer route consists of several types of habitats, although some may be very similar. The third type of dispersal mechanism is called a sweepstakes route , which is dispersion caused by chance combinations of favorable conditions. This differs from a filter route in that the organisms tat traverse a sweepstakes route are not normally able to spend their whole life history en route. For example, bird watchers are well familiar with accidentals or bird species that occur in non-native areas due to a variety of reasons.