Many factors contribute to the endangerment of animals, excessive hunting, exposure to pesticides and other pollutants, as well as ongoing competition between species. But the most important cause is habitat loss as a result of human exploitation and encroachment. Habitat loss can endanger species in three ways. First, destruction of a habitat means that species using only that habitat have no place to live and will disappear. If the habitat is unique, such species may rapidly become extinct. Second, modification of a habitat, for example, by removing older trees or introducing exotic species can cause habitat-dependent species to gradually disappear. Their fate depends on how the habitat features they rely upon are modified. Third, road building or development can fragment a habitat so that species dependent on that habitat become more vulnerable. Without intensive monitoring and management, the species may die out. Hunting restrictions, heightened public consciousness through conservation education, and regulations banning dangerous pollutants have contributed to the recovery of some endangered species. The problems of habitat loss remain unresolved, however. Growing human populations and increased exploitation of natural resources make habitat loss a major concern for conservationists.