GEF

Unit 5  |  The Importance of Biodiversity 115 The loss of biodiversity is especially severe in tropical forests. These forests, located in Central and South America, Africa, and Asia, are vital storehouses for the Earth’s biodiversity. Although tropical forests cover only about two percent of the total land area of the planet, they contain about fifty percent of Earth’s species. The World Resources Institute reports 39 percent of the world’s remaining tropical forests are under moderate or high threat of destruction. At present, tropical forests are being deforested at a rate of 27,000 to 66,000 square miles annually, equal to fifty soccer fields per minute. Logging, farming, road construc- tion, and urban development all add to deforestation. Poverty can be a driver of deforestation for people without alternative ways to make a living and obtain needed resources. Although oceans are often neglected in discussions of biodiver- sity and conservation, marine habitats are crucially important to the Earth’s ecological health. The “tropical forests of the seas,” coral reefs , are vital storehouses for biodiversity. These rich habitats are found in shallow tropical oceans in several regions of the world, including Australia, Southeast Asia, and the Caribbean. Coral reefs contain vastly greater biodiver- sity than the open ocean. They cover less than one tenth of 1 percent of the ocean’s surface, but support one quarter of the Earth’s marine species. At the base of coral reef ecosystems are colonies of coral polyps that rely upon a symbiotic relationship with algae for survival. Corals become bleached and die when their algae are expelled, which can occur due to pollution, higher ocean temperatures, or lowered pH . Climate change, ocean acidifi- cation , and destructive human activities, such as blast fishing and coral harvesting, are threatening coral reefs worldwide. Conservationists are promoting protected reef areas and edu- cation about their importance. CORAL REEF Highly biodiverse colonies of tiny marine animals, fish, and other organisms. SYMBIOTIC Amutually beneficial relation- ship between two species. PH A measure of the acidity or basicity of a liquid, like seawater. Lowered pH in the oceans has negative effects on marine organisms. OCEAN ACIDIFICATION An ongoing decrease in the pH of the oceans, due to uptake of atmospheric car- bon dioxide. ?  DID YOU KNOW There are additional reasons why the protection of biodi- versity is important. Species extinctions and biodiversity loss inevitably has a greater impact on hunter-gatherer communities than on urban residents.