The breaking-up of the rain forest prevents species from moving between natural areas, further weakening them. Logging further encourages fragmentation. As those roads are built and pockets of deforested areas spread, edge effects occur which reduce the number of plants and animals and threaten the rain forest even more. The roads and farms allow hunters and non-native animals and predators access to a much larger portion of rain forest. To say the Amazon Rain Forest is threatened by deforestation means that we must consider more than just the loss of homes for plants and animals.
Fragmentation causes even more harm.
Efforts to protect the Amazon Rain Forest and to protect the species who live there must take into account how deforestation occurs. Johns, Lucia and Freida Simms. Environmental Policy Division, Congressional Research Service.