Summary
The core threats to biodiversity are human population growth and unsustainable resource use. To date, the most significant causes of extinctions are habitat loss, introduction of exotic species, and overharvesting. Climate change is predicted to be a significant cause of extinctions in the coming century. Habitat loss occurs through deforestation, damming of rivers, and other activities. Overharvesting is a threat particularly to aquatic species, while the taking of bush meat in the humid tropics threatens many species in Asia, Africa, and the Americas. Exotic species have been the cause of a number of extinctions and are especially damaging to islands and lakes. Exotic species’ introductions are increasing because of the increased mobility of human populations and growing global trade and transportation. Climate change is forcing range changes that may lead to extinction. It is also affecting adaptations to the timing of resource availability that negatively affects species in seasonal environments. The impacts of climate change are greatest in the arctic. Global warming will also raise sea levels, eliminating some islands and reducing the area of all others.
Glossary
bush meat
wild-caught animal used as food (typically mammals, birds, and reptiles); usually referring to hunting in the tropics of sub-Saharan Africa, Asia, and the Americas
chytridiomycosis
disease of amphibians caused by the fungus Batrachochytrium dendrobatidis; thought to be a major cause of the global amphibian decline
exotic species
(also, invasive species) species that has been introduced to an ecosystem in which it did not evolve
tragedy of the commons
economic principle that resources held in common will inevitably be overexploited
white-nose syndrome
disease of cave-hibernating bats in the eastern United States and Canada associated with the fungus Geomyces destructans