Shadows Over the Rain Forest
SEEN from an aircraft, the Amazon rain forest reminds you of a continental-size tufted carpet, looking as green and pristine now as it did when Orellana put it on the map. As you slog through the hot, humid forest on the ground, dodging insects the size of small mammals, you find it hard to tell where reality ends and fantasy takes over. What appear to be leaves turn into butterflies, lianas into snakes, and chunks of dry wood into startled rodents that scurry away at top speed. In the Amazon forest, fact is still blurred with fiction.
“The greatest irony,” notes one observer, “is that Amazon reality is as fantastic as its myths.” And fantastic it is! Picture a forest as large as Western Europe. Stuff it with over 4,000 different species of trees. Embellish it with the beauty of more than 60,000 species of flowering plants. Color it with the brilliant hues of 1,000 species of birds. Enrich it with 300 species of mammals. Saturate it with the buzz of perhaps two million species of insects. Now you see why anyone describing the Amazon rain forest ends up using superlatives. No lesser comparisons do justice to the teeming biological bounty of this largest tropical rain forest on earth.
The Isolated “Living Dead”
Ninety years ago the American writer and humorist Mark Twain described this fascinating forest as “an enchanted land, a land wastefully rich in tropical wonders, a romantic land where all the birds and flowers and animals were of the museum varieties, and where the alligator and the crocodile and the monkey seemed as much at home as if they were in the Zoo.” Today, Twain’s witty remarks have acquired a sober twist. Museums and zoos may soon be the only homes left for a growing number of the Amazon’s tropical wonders. Why?
The leading cause is obviously man’s hacking away at the Amazon rain forest, rooting out the natural home of the region’s flora and fauna. However, besides wholesale habitat destruction, there are other—more subtle—causes that are turning plant and animal species, even though still alive, into “living dead.” In other words, authorities believe that there is nothing that can stop the species from dying out.
One such cause is isolation. Government officials with a fancy for conservation may ban the chain saw from a patch of forest to secure the survival of species living there. However, a small forest island offers these species the prospect of eventual death. Protecting the Tropical Forests—A High-Priority International Task gives an example to illustrate why small forest islands fail to support life for very long.
Tropical-tree species often consist of male and female trees. To reproduce, they get help from bats that carry pollen from male to female flowers. Of course, this pollination service works only if the trees grow within the bat’s flying radius. If the distance between a female tree and a male tree becomes too great—as often happens when a forest island ends up surrounded by a sea of scorched earth—the bat cannot bridge the gap. The trees, notes the report, then turn into “‘living dead’ since their long-term reproduction is no longer possible.”
This link between trees and bats is only one of the relationships making up the Amazonian natural community. Simply put, the Amazon forest is like a huge house that provides room and board to an assortment of different but tightly interrelated individuals. To avoid overcrowding, the inhabitants of the rain forest live on different stories, some close to the forest floor, others away up in the canopy. All residents have a job, and they work around the clock—some in the day, others during the night. If all species are allowed to do their share of the work, this complex community of Amazonian flora and fauna functions with clockwork precision.
The Amazon’s ecosystem (“eco” comes from oiʹkos, the Greek word for “house”) is, however, fragile. Even if man’s interference in this forest community is limited to exploiting a few species, his disruption reverberates throughout all the stories of the forest house. Conservationist Norman Myers estimates that the extinction of a single plant species can eventually contribute to the death of as many as 30 animal species. And since most tropical trees, in turn, depend on animals for seed dispersal, man’s wiping out animal species leads to the extinction of the trees they service. (See the box “The Tree-Fish Connection.”) Like isolation, disrupting relationships assigns more and more forest species to the ranks of the “living dead.”
Small Cuts, Small Losses?
Some justify deforestation of small areas by reasoning that the forest will bounce back and grow a fresh layer of greenery over a stretch of clear-cut land in much the same way our body grows a fresh layer of skin over a cut in a finger. Right? Well, not quite.
It is true, of course, that the forest grows back if man leaves a deforested patch alone long enough. But it is also true that the new layer of vegetation resembles the original forest no more than a poor photocopy resembles a crisp printout. Ima Vieira, a Brazilian botanist, studied a century-old stretch of regrown forest in the Amazon and found that of the 268 tree species that used to flourish in the old forest, only 65 form a part of the regrown forest today. This same difference, says the botanist, holds true for the region’s animal species. So although deforestation is not, as some claim, turning green forests into red deserts, it is turning parts of the Amazon rain forest into a weak imitation of the original.
In addition, cutting even a small stretch of forest often destroys many plants and animals that grow, crawl, and clamber in only that spread of forest and nowhere else. Researchers in Ecuador, for instance, found 1,025 plant species in a certain area of seven tenths of a square mile [1.7 sq km] of tropical forest. More than 250 of those species grew nowhere else on earth. “A local example,” says Brazilian ecologist Rogério Gribel, “is the sauim-de-coleira (pied bare-faced tamarin, in English),” a small, charming monkey that looks as if it were wearing a white T-shirt. “The few remaining ones live only in a small forest stretch near Manaus in central Amazon, but the destruction of that small habitat,” says Dr. Gribel, “will wipe out this species forever.” Small cuts but big losses.
Rolling Back the “Rug”
Outright deforestation, however, is throwing the most alarming shadow over the Amazon rain forest. Road builders, loggers, miners, and hordes of others are rolling back the forest like a floor rug, razing entire ecosystems in the blink of an eye.
While there is deep disagreement about the exact figures for Brazil’s annual rate of forest destruction—conservative estimates put it at 14,000 square miles [36,000 sq km] per year—the total amount of Amazon rain forest already destroyed may be more than 10 percent, an area larger than Germany. Veja, Brazil’s leading newsweekly, reported that some 40,000 forest fires lit by slash-and-burn farmers raged across the country in 1995—five times more than the year before. Man is torching the forest with such vigor, alerted Veja, that parts of the Amazon resemble an “inferno on the green frontier.”
Species Are Going—So What?
‘But,’ some ask, ‘do we need all those millions of species?’ Yes, we do, argues conservationist Edward O. Wilson, of Harvard University. “Since we depend on functioning ecosystems to cleanse our water, enrich our soil and create the very air we breathe,” says Wilson, “biodiversity is clearly not something to discard carelessly.” Says the book People, Plants, and Patents: “Access to abundant genetic diversity will be the key to human survival. If diversity goes, we will soon follow.”
Indeed, the impact of species destruction goes far beyond felled trees, threatened animals, and harassed natives. (See the box “The Human Factor.”) The downsizing of forests may affect you. Think of this: A farmer in Mozambique cutting cassava sticks, a mother in Uzbekistan taking a birth-control pill, a wounded boy in Sarajevo being given morphine, or a customer in a New York store savoring an exotic fragrance—all these people, notes the Panos Institute, use products that sprang from the tropical forest. The standing forest thus serves people around the world—including you.
No Feast, No Famine
Granted, the Amazon rain forest cannot provide a worldwide feast, but it can help to prevent a worldwide famine. (See the box “The Fertility Myth.”) In what way? Well, in the 1970’s, on a large scale, man began to sow a few plant varieties that produced bumper crops. Though these superplants have helped to feed an additional 500 million people, there is a catch. Since they lack genetic variation, they are weak and vulnerable to disease. A virus can decimate a nation’s supercrop, triggering famine.
So to produce more resilient crops and avert starvation, the UN Food and Agriculture Organization (FAO) now urges the “use of a broader range of genetic material.” And that is where the rain forest and its original inhabitants come in.
Since tropical forests house more than half the world’s plant species (including some 1,650 species that have potential as food crops), the Amazon nursery is the ideal spot for any researcher looking for wild plant species. In addition, the forest’s inhabitants know how to utilize these plants. Brazil’s Cayapo Indians, for instance, not only breed new crop varieties but also preserve samples in hillside gene banks. Crossbreeding such wild crop varieties with the vulnerable domesticated crop varieties will bolster the strength and resilience of man’s food crops. And that boost is urgently needed, says FAO, for “a 60% increase in food output is necessary in the next 25 years.” In spite of this, forest-crushing bulldozers keep pushing deeper into the Amazon rain forest.
The consequences? Well, man’s destroying the rain forest is much like a farmer’s eating his seed corn—he satisfies his immediate hunger but endangers future food supplies. A group of experts on biodiversity recently warned that “the conservation and development of the remaining crop diversity is a matter of vital global concern.”
Now step into the forest “pharmacy,” and you will see that man’s fate is intertwined with tropical vines and other plants. For instance, alkaloids extracted from Amazonian vines are used as muscle relaxants prior to surgery; 4 out of 5 children with leukemia are helped to live longer thanks to the chemicals found in the rosy periwinkle, a forest flower. The forest also provides quinine, used to fight malaria; digitalis, used to treat heart failure; and diosgenin, used in birth-control pills. Other plants have shown promise in fighting AIDS and cancer. “In the Amazon alone,” says a UN report, “2,000 species of plants used as medicines by the native population and that have pharmaceutical potential have been recorded.” Worldwide, says another study, 8 out of every 10 persons turn to medicinal plants to treat their ills.
So it makes sense to save the plants that save us, says Dr. Philip M. Fearnside. “Loss of Amazonian forest is considered a serious potential setback to efforts to find cures for human cancer. . . . The notion that the shining achievements of modern medicine permit us to dispense with a major portion of these stocks,” he adds, “represents a potentially fatal form of hubris.”
Nevertheless, man goes on destroying animals and plants faster than they can be found and identified. It makes you wonder: ‘Why is the deforestation continuing? Can the trend be reversed? Does the Amazon rain forest have a future?’
[Box on page 8]
The Fertility Myth
The idea that Amazon soil is fertile, notes the magazine Counterpart, is a “myth that is hard to dispel.” In the 19th century, explorer Alexander von Humboldt described the Amazon as the “granary of the world.” A century later, U.S. President Theodore Roosevelt likewise felt that the Amazon promised good farming. “Such a rich and fertile land,” he wrote, “cannot be permitted to remain idle.”
Indeed, the farmer who believes as they did finds that for a year or two, the land gives a decent crop because the ashes of burned trees and plants serve as fertilizer. After that, however, the soil turns barren. Although the forest’s lush greenery promises rich soil beneath, the soil is, in reality, the forest’s weak side. Why?
Awake! talked with Dr. Flávio J. Luizão, a researcher at the National Institute for Research in the Amazon and an expert on rain-forest soil. Here are some of his comments:
‘Unlike many other forest soils, most soil in the Amazon basin doesn’t get nutrients from the bottom up, from decomposing rock, because the parent rock is nutrient poor and lies too deep below the surface. Instead, the leached soil gets nutrients from the top down, from rain and litter. However, both raindrops and fallen leaves need help in turning nutritious. Why?
‘Rainwater falling on the rain forest doesn’t have many nutrients itself. However, when it hits the leaves and runs along the trunks of the trees, it picks up nutrients from leaves, branches, moss, algae, ants’ nests, dust. By the time the water seeps into the soil, it has turned into good plant food. To keep this liquid food from simply flowing into the creeks, the soil uses a nutrient trap formed by a mat of fine roots spread throughout the first few inches of the topsoil. A proof of the trap’s effectiveness is that the creeks receiving this rainwater have even poorer nutrient content than the forest soil itself. So the nutrients get into the roots before the water gets into the creeks or rivers.
‘Another source of food is litter—fallen leaves, twigs, and fruits. Some eight tons of fine litter ends up on one hectare [two and a half acres] of forest floor each year. But how does the litter get under the surface of the soil and into the plants’ root systems? Termites help out. They cut disk-shaped pieces out of the leaves and carry these pieces into their subterranean nests. Especially during the wet season, they are an active bunch, moving an amazing 40 percent of all forest-floor litter underground. There, they use the leaves to build gardens for growing fungus. This fungus, in turn, decomposes the plant material and releases nitrogen, phosphorus, calcium, and other elements—valuable nutrients for plants.
‘What do the termites get out of it? Food. They eat the fungi and may swallow some bits of leaves as well. Next, the microorganisms in the termites’ intestines get busy transforming the termites’ food chemically, so that, as a result, the insects’ excretion becomes nutrient-rich plant food. So rainfall and the recycling of organic matter are two of the factors that keep the rain forest standing and growing.
‘It’s easy to see what happens if you clear-cut and burn the forest. There is no longer a canopy to intercept rainfall or a layer of litter to be recycled. Instead, torrential rains hit the bare soil directly with great force, and their impact hardens the surface. At the same time, sunlight falling straight on the soil increases the surface temperature and compacts the soil. The result is that rainwater now runs off the land, feeding not the soil but the rivers. Nutrient loss from deforested and burned land may be so great that the streams near deforested areas even suffer from an excess of nutrients, endangering the lives of aquatic species. Clearly, if left alone, the forest sustains itself, but man’s interference spells disaster.’
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The Human Factor
Disruption and deforestation are harming not only plants and animals but humans as well. Some 300,000 Indians, a remnant of the 5,000,000 Indians that once inhabited Brazil’s Amazon region, still coexist with their forest environment. The Indians are increasingly disturbed by loggers, gold seekers, and others, many of whom consider the Indians “obstacles to development.”
Then there are the caboclos, tough people of mixed white and Indian ancestry whose forefathers settled in Amazonia some 100 years ago. Dwelling in stilted sheds along the rivers, they may never have heard of the word “ecology,” but they live off the forest without destroying it. Yet, their day-to-day existence is affected by the waves of new immigrants now entering their forest home.
In fact, throughout the Amazon rain forest, the future of some 2,000,000 nut gatherers, rubber tappers, fishermen, and other natives, living harmoniously with the cycles of the forest and the rhythms of the rivers, is uncertain. Many believe that efforts to preserve the forest should go beyond protecting mahogany trees and manatees. They should protect the human forest dwellers as well.
[Box/Pictures on page 9]
The Tree-Fish Connection
During the rainy season, the Amazon River rises and engulfs the trees growing in lowland forests. At the peak of the flooding, most trees in these forests bear fruit and drop their seeds—but there are, of course, no submerged rodents around to disperse them. Enters the tambaqui fish (Colonnonea macropomum), a floating nutcracker with a keen sense of smell. Swimming among the branches of submerged trees, it smells out the trees that are about to drop seeds. When the seeds fall into the water, the fish crushes the shells with his powerful jaws, swallows the seeds, digests the fleshy fruit around them, and drops the seeds on the forest floor to germinate when the floodwaters recede. Fish and tree benefit. The tambaqui stores fat, and the tree produces offspring. Cutting those trees endangers the survival of the tambaqui and some 200 other species of fruit-eating fish.
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Bats carry pollen from male to female flowers
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Your nursery and pharmacy
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Fire threatens the green frontier
Philip M. Fearnside