Scientists estimate that there could be......million species in these rain forests
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There is nothing like a tropical rain forest for replacing arrogance with awe. Who could enter these primordial places, these untamed Edens, and not be wonderstruck? Dark and mysterious even in daytime, rain forests inspire respect. They are one of Nature's last frontiers, alive with flora and fauna seen rarely or never by human beings, and colonized by a handful of indigenous tribes that have had little or no contact with the outside world. Vast, fecund and biologically diverse, rain forests are bountiful and seemingly inexhaustible ecosystems that have supplied the human race with a staggering treasure trove including timber, fruit, spices and medicines. Although much more bounty lies in wait, the pace of discovery in the rain forest is naturally slow. The sheer number of plants to study is staggering and scientific experimentation takes time and money. Even when a chemical needle is found in a rain forest haystack, it still takes years to get a new drug to market.
The English naturalist and author Gerald Durrell assailed those who would ravage the rain forests loggers, ranchers and miners, for acting "with the savage, unthinking ferocity of a troupe of drunken apes in art gallery". But, he added, "whereas pictures can be repainted, tropical rain forests can't be recreated". Indeed, what could replace the wondrous electric fish of the Amazon River, the poison-sweating frogs of Panama, or the host of plants and animals whose secrets and potential benefits have yet to be fathomed? In a word, nothing. When they are gone, they are.
The world's rain forests still hold a host of secrets, many of which are being slowly unravelled as new discoveries of plant and animal life are made. According to conservative estimates, about 30 million species of plants and animals - more than half of all life forms on Earth - live in the tropical rain forests. But some scientists suggest there could be up to 80 million or more species living in this mysterious and still largely unexplored realm. This higher figure could very well be proved right as researchers probe the forest canopy, the treetop network of leaves, vines and branches that forms a world within a world. In these huge green expanses scores of meters above the forest floor, sky gardens of orchids and philodendrons bloom without benefit of soil. Birds avoid the rain by hanging upside down beneath broad leaves. Green iguanas climb aloft to bask nearer the tropical sun. Sloths dangle motionless for hours, avoiding eagles and other predators. And everywhere is the buzz and flutter of insects, which inhabit the rain forest in incredible variety and numbers. While new species of larger creatures such as a dwarf deer identified in Vietnam's Vu Quag forest in April are rarely discovered, the insect world still offers plentiful newness, especially in the rain forest canopy.
This treetop world enchants Andrew Mitchell, an Oxford-based naturalist and author who is program director for Earth Watch, an organisation that matches volunteer members of the public with scientific and conservation projects worldwide. Mitchell has extensively explored the rain forests of Asia and Latin America, making perilous climbs into the canopy, which he describes as the "penthouse where the trees have their sex lives". The canopy is physically and biologically the most active part of any rain forest. With its complex system of interdependence among animals, plants and insects, it is also the least understood. "Half of all life lives there and it's where the reproductive biology of trees goes on", explains Mitchell. "If we're trying to save rain forests, we won't get anywhere unless we understand how these trees reproduce". As commercial development encroaches ever deeper into once-remote areas, saving the rain forests is becoming an increasingly urgent task. Some 6% of Earth's land area is rain forest, according to the World Wide Fund for Nature, and more than 1% of that - about 17 million hectares - is being lost each year through logging, mining and agriculture.