Urban Jungle : Lush Wonders of the Amazon Are Contained in Zoological Park

Visitors line up at the “border” of Amazonia waiting to have their passports stamped so they can enter a world many have never experienced. Lush greenery and the warm, moist air suggest a tropical paradise. But Amazonia is not a country. It is a trailblazing new exhibit on the grounds of the National Zoological Park in Washington.

Outside, winter winds may be howling. Or it may be yet another hot and muggy summer day. But the weather never changes inside Amazonia. The heat, humidity and rich diversity of tropical forest life are on permanent display in temperate North America.

Amazonia--a seven-year design and construction effort--is an intended departure from typical zoo exhibits, Dr. Michael Robinson, director of the National Zoo, said. It is the largest exhibit building to be constructed at the zoo in more than 50 years. It includes a cascading tropical river that displays many unusual fish; a rain forest featuring 358 species of plants and dozens of animals, and a re-created biologist’s field station where visitors gain insights into the intricacies of tropical ecology and scientific methods of study.

As part of Robinson’s “Biopark” concept--displaying all aspects of life on Earth--not merely animals isolated from their natural contexts--Amazonia aims for a total sensory experience of major ecosystems along the mighty Amazon of South America. For many people in North America, Robinson said, the exhibit may be their one chance to experience the wonder of a tropical rain forest.

And what a wonder it is. The real Amazon Basin rain forest of South America would more than cover the continental United States. In recent years, scientists have issued a clarion call about the value of this vast and complex ecosystem for the entire world. Like all tropical forests, the Amazon helps regulate the global climate and influences many other global ecosystem functions.

In addition, tropical forests contain thousands, perhaps millions, of plants and animals yet to be identified by scientists. This forest life, scientists say, may represent rich new reserves of agricultural products and chemical compounds for medicine and industry.

But the destruction of tropical forests worldwide continues. The World Resources Institute estimates that some 50% of the world’s tropical forest areas has already been lost or degraded since 1900.

In the Amazon Basin--where the yearly loss of rain forest is estimated at 4 million to 20 million acres--”there has been a decrease in the increasing rate of destruction,” Richard Bierregaard of the Smithsonian’s National Museum of Natural History, said. He added, however, that this slowdown follows a huge pulse of destruction--mostly from burning--in the late 1980s. At that time, landowners in the Amazon region set about clearing as much forest as possible before new government conservation regulations were enacted to control the widespread practice.

Bierregaard is an expert on tropical forest ecosystems, especially the Amazon Basin. Since 1979, he has directed the Biological Dynamics of forest Fragments program, a large-scale experiment originally begun by tropical forest expert Tom Lovejoy, who is now the Smithsonian’s assistant secretary for external affairs.

Located just north of the Brazilian city of Manaus, the forest fragments project--through controlled experiments--is documenting what happens as tracts of forest are isolated by human encroachment and decreased in size.

In the Amazon Basin, Bierregaard said, “there is a great deal of pressure to clear land anytime access to virgin forest becomes possible through new roads or rail lines.” Past laws in Brazil, he said, considered clearing “an improvement,” which then conferred ownership and qualified people for various state subsidies. Converted to cattle ranches, cleared land could return a profit for minimal investment.

But forest destruction is not the only threat to the Amazon ecosystem. Gold fever has hit Amazonia. Increasingly the region’s extensive network of rivers, including the Amazon River itself, is being poisoned through mining operations. Miners dredge silt from rivers, the silt is mixed with mercury to remove gold, and the residue is dumped back into the river.

Few mining operations bother with procedures that would prevent or reduce mercury contamination. “Some rivers may be full of mercury,” Bierregaard said.

The new Amazonia exhibit highlights some of the incredible life forms in these rivers that may be threatened. In fact, visitors to the exhibition are greeted by the roar of a huge cascading waterfall.

The waterfall introduces the “flooded forest” and the exhibit’s main concept: the interdependence of rain forest life, Jaren Horsley, the curator of Amazonia, said. The flooded forest section depicts that area of the Amazon Basin where streams seasonally overflow their banks, allowing fish and other river inhabitants to move into the forests to harvest fruits and other food items lying on the forest floor.

In the real Amazon, there are virtually thousands of fish species, the zoo’s Robinson said. The Amazon River is home to some 250 different species of catfish alone.

Trees rooted in the flooded land of Amazonia support countless rain forest orchids, bromeliads and vines. Hummingbirds, monkeys and waterfowl complete the variety of life greeting Amazonia visitors. In the background of the forest, a villager’s hut and child’s canoe remind visitors that humans, too, are present in the complex Amazon environment.

Four floor-to-ceiling paintings offer vistas of the Amazon River Delta and its principal tributary, the Rio Negro. Opposite the paintings is a series of giant, naturalistic aquariums simulating deep-river pools that open to the forest above.

At the next stop is the field station of imaginary biologist, “Dr. Brasil.” The curious can look over the equipment, notes and specimens of this scientist who is “out in the field.”

Upstairs, visitors feel a wave of tropical air come over them as they enter the forest--what Robinson describes as a “green cathedral.” High overhead, a sloth hangs upside down, feeding on leaves. Tanagers and hummingbirds dart from branch to branch.

Last year, truckloads of tropical plants--including 50 species of trees--were delivered to Washington and carefully planted in the new exhibition. Misting equipment and climate-control devices impart the true feeling of the forest’s heat and humidity in which the plants thrive.

“We want people to realize that plants are not just a backdrop for animals,” Horsley said, but that “a plant is a living organism with a strategy for its own survival dictated by its evolution.” Trees in the exhibit will produce fruit that drops into an “feeds” the river below. “We want an upbeat, fun approach that helps people see plants in a new way for the first time.”

Amazonia staff and trained volunteers provide an extra dimension to the visitor’s experience by giving personal responses to questions and pointing out subtleties of plants and animals that might otherwise by overlooked. “We’ve built an exhibit designed to create excitement,” Horsley said. “It’s only this kind of rich experience that leaves a lasting impression on people.”

In the Amazon, Bierregaard takes heart in the increased awareness of the forest’s value. In the last 10 years, he said, numerous environmental groups have formed in Brazil to help educate people about the forest and to protect its biological diversity.

People are apparently getting the message, Bierregaard said. Some timber producers, who in the past replanted huge tracts of logged areas with single-species forests, now find that maintaining a diverse flora eliminates the need for insecticides or other costly methods for eradicating pests. “Simple economics have dictated an environmentally benign solution to an ecological problem.”

In the same manner, Robinson--who spent more than 20 years living and working in Panama at the Smithsonian Tropical Research Institute--wants Amazonia visitors “to be impressed by the sheer wonder of the Amazon’s biological diversity--to understand, before it is lost--that it is something to be cherished for all time.”

And Horsley emphasized that the overall experience of Amazonia should be positive. “I want people to fall in love with the Amazon as a place.”