Deforestation has several negative consequences for both plants and animals. Forests cover about one third of the surface of the earth, but this is changing due to their rapid destruction. Rainforests, in particular, support a huge diversity and abundance of animal life, with many species living in rainforests that have not even been described.
Trees create shelter from the elements, like wind and sun, and provide a place for animals to feed, nest, breed and hide from predators. The ecosystem is fragile, and any disturbance can have widespread ramifications. Deforestation is usually caused by slash and burn agricultural practices or from logging by the timber industry.
Destroying trees can directly harm animals that may have built nests there, or by changing microclimates. Animals that heavily rely on trees may be unable to adapt to a new habitat. That is the case for species that are very specialized. This can mean that deforestation can cause them to become endangered; for example, the Red-cockaded Woodpecker in North America is endangered due to deforestation. This woodpecker species only nests in trees that are of a mature age and have a certain type of fungus growing on them. This means that the species is likely to go extinct unless a sufficient number of mature trees that have the fungus are preserved.
Forests have the highest biodiversity in the world, which means there are complex food webs present. Destroying trees may mean less food for animals that rely on fruits, nuts and leaves produced by the trees. This means that the forest will be unable to support a large population of a species. As population sizes shrink, so does the genetic variation, which in turn leads to increased risk of extinction in the future. The Mountain Gorilla is an example of a species that is now critically endangered with greatly decreased genetic variation. This animal relies heavily on trees and vines for food and is being pushed into more inhospitable habitat, higher up the mountain into colder conditions, as humans encroach more and more on their habitat. This means increase in diseases and decreased numbers of gorillas.
Another problem with deforestation is fragmentation. As trees are removed, large continuous stretches of forest are interrupted and fragmented. Fragmentation reduces dispersal of species. This, again, can cause decreased genetic variation and increased extinction risk. Animals are put in dangerous situations at the edge of their habitat. They may be hit by vehicles or killed by poachers while moving to another forest patch. Animals with large territories and home range sizes are particularly vulnerable to problems of decreased habitat size.
Deforestation has a devastating impact on forest animals. Besides the impact on large or obvious animals, such as birds and gorillas, there is the impact on insects and many other invertebrates that are so crucial to the health of food webs and ecosystem dynamics. Indicator species, such as frogs that live in these forests, are highly sensitive to change and are at real risk of extinction as deforestation continues.