Isolation or fragmentation restricts the range of plants and animals, exposing them to disease or predators. Edge effects also which allow weather and non-native species easy access to the borders of the forest. As part of the rain forest is cut down by farmers, ranchers, and loggers, the plants and animals are left to die. If all deforestation occurred along the outside boundaries of the forest, then some of the species could move deeper into the Amazon to survive. However, deforestation does not happen that way.
Fragmentation further weakens the rain forest, producing pockets of deforested areas.
These pockets of forest do not have the biological diversity needed to sustain the plants and animals that live there. 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.