|
|
| The
Tropical Extinction Debate: Key Facts For the vast majority of scientists, none of the points below are in dispute Tropical rainforests are the biologically richest ecosystems on Earth. Many rainforests have a large number of locally endemic species that are found nowhere else on the planet. Old-growth tropical forests are disappearing at an alarming pace—averaging 13 million hectares per year, equivalent to about 50 football fields a minute. In many areas of the tropics, such as the Philippines, the Brazilian Atlantic forests, and West Africa, more than 90 percent of the old-growth forests have already been destroyed. In other areas, such as Costa Rica and the Dominican Republic, old-growth forests have been sharply reduced, but secondary forests are regenerating on abandoned or degraded pastures and farmland. From a conservation perspective, old-growth forests are superior to secondary forests, as they contain ecologically specialized species found nowhere else. However, secondary tropical forests can sometimes sustain surprising levels of biodiversity, especially those that are more than 20 years old and growing near old-growth forest, which provides a source of seeds and animal pollinators and seed dispersers. In addition to habitat destruction, tropical biodiversity is also imperiled by global warming, because many species in the tropics are likely thermal specialists that have little tolerance of rising temperatures. From a global-warming perspective, tropical deforestation causes about one-fifth of all human carbon emissions today. Thus, protecting old-growth tropical forests will help to slow harmful climate change. Secondary tropical forests are also important, as they help to remove carbon dioxide already present in the atmosphere. Old-growth rainforests are in serious danger in many parts of the world, and are in dire need of protection—both for biodiversity and to help slow global warming. Secondary forests are important too, and should be encouraged wherever old-growth forests have been reduced and more generally to help remove carbon dioxide from the atmosphere. Learn more about the fate of tropical species. See presentations from this symposium. See background for additional information.
________________________________________
|