In Washington, scientists gathered to debate the present and future of the world's tropical rainforests.
Tropical rainforests around the globe have the greatest concentration of species and the most bio-diversity on our planet. But now large areas of rainforest have been cleared and many species have disappeared or are on their way to extinction. And scientists are discussing the chances for survival and the future of the rainforest.
"About 25 percent of the known living species of mammals are considered to be in danger of extinction, most of these in tropical rainforest areas," says Cristian Samper, director of the National Museum of Natural History, and organizer of the event.
He says at least one fourth of the world's rainforest has been lost over the last 150 years.
"The most woring part is that when you look at the next 50 years, we estimate we may lose another 25 percent," he said.
Samper and other scientists agree that the loss is due to a combination of factors but deforestation, for timber and agriculture, is the most important.
Additional threats include over-population, pollution and climate change, invasive species, and hunting. The Smithsonian Tropical Research Institute in Panama is the world's oldest and largest research center for tropical biology.
Eldredge Bermingham is the director. He says the rainforest in some regions are in critical condition. "The biggest worry right now in terms of extinction is South East Asia," Bermingham said.
Nigel Stork is a scientist at the University of Melbourne in Australia. He says most of the species lost are insects, and they play a key role.
He explained what happened when cattle were introduced to Australia decades ago. "There were no native organisms to break down cow dung and thousands of hectares of land were getting covered with cow dung which instead of breaking down in 3 months as it does down here (in the United States)," Stork explained. "It takes 7 years in Australia. And there were lots of flies."
Elizabeth Bennett at the Hunting and Wildlife Trade Program of the Wildlife Conservation Society, says commercial hunting is now a global business, supplying developed countries with exotic meats, pets, furs and trophies like elephant tusks and lion heads. "In the year 2000, Sumatra was exporting 25 tons of turtles per week to China," she added.
Bennett says logging companies have built roads into remote areas, making them vulnerable to hunters. But the most horrific prospect is the "empty forest syndrome". "The empty forest syndrome is a phenomenon where you have a pretty intact forest. So if you are looking from a satellite picture or airplane, it looks like a really nice forest," she said. "But it has been very heavily hunted and so it has fallen silent."
Many scientists agree that while the rainforest could survive in one form or another, many species of large animals may not. And, in the end, we might only be left with vegetation in a world that has lost its balance.