At the OTS’s fortieth-anniversary symposium, the group celebrated such educational and research successes, but also pondered how to apply twenty-first-century science and education to the massive challenges of understanding and saving the planet’s tropical ecosystems. “The last several decades have revealed that the diversity of life is far greater than we had even imagined,” said E.O. Wilson, a renowned biologist and one of OTS’s founders, speaking at the symposium. The vast majority of species are concentrated in tropical forests, he said, and are being destroyed at an alarming rate, potentially “inflicting a heavy price on future generations in economics, in security, and in spirit.”

He and his fellow biologists are proposing a massive international “systematics” project to catalogue the approximately 90 percent of the millions of Earth’s species that remain unknown. The result of the multi-decade effort, which he hopes will be funded by governments worldwide, would be an online “encyclopedia of diversity.” Without such a catalogue, Wilson said, we have no way of even knowing what we are in danger of losing.

Fang face: the vampire bat, one of nearly 65 bat species in Costa Rica, top Red menace: the strawberry poison dart frog, whose deadly toxin is used on hunting arrows, middle Danger under glass: a scorpion is examined in the safest possible way, above

To OTS President Gary Hartshorn, OTS and its scientific stations will play a central role not only in cataloguing species, but also in understanding their role in the intricate web of ecology. A fundamental advantage of such stations is their longevity, he says. “Many ecologists have learned that long-term data sets that span decades are extraordinarily valuable. Because of the initiative of OTS and of individual researchers, we have projects that have been going on here at La Selva for up to forty years, and these are hugely important and very valuable.”

A prime example of the value of such long-term data is the record of the growth of La Selva’s massive trees, maintained by ecologists David and Deborah Clark for nineteen years. “If someone new wants to work on trees at La Selva,” Deborah Clark says, “she or he doesn’t have to come in and start from scratch and say, ‘What is this species? When does it produce seeds? Who eats it? What does it need to regenerate?’” Instead, researchers “can come in and build that fundamental knowledge base in a very quick time frame and get to what we often say are the much more interesting ecological questions there.”

The latest discovery by the Clarks, who are ecologists at the University of Missouri-St. Louis and former scientific directors of La Selva, dramatically illustrates the scientific value of such data. Every year since 1984, the Clarks and their Costa Rican and U.S. colleagues have made painstaking measurements—precise to less than a millimeter—of the growth of La Selva’s giant trees.

These measurements recently revealed a startling discovery: During warmer years, the trees grew less and expelled more carbon dioxide. “A major, tacit assumption, I think, of 90 percent of us working at La Selva was that we were working in a tropical rain forest, which means equitable climate, which means every year’s the same,” says Deborah Clark. However, the new finding “made it very clear to us that, if our forest is very sensitive to small, inter-year differences in climate, it’s certainly going to be affected with these global changes going on right now.” The world’s climate could be entering what she calls “very scary territory,” in which the rise in global temperature, along with accompanying drought, could inflict enormous damage to tropical forests and increase the amount of carbon dioxide in the planet’s atmosphere.

Many ecologists had assumed that tropical forests would grow faster with higher levels of carbon dioxide, buffering the global increase in the greenhouse gas. In contrast, the scenario the Clarks’ research hints at has been ominously named the Armageddon Model. More research is needed to understand how old-growth trees take up or release carbon, and that is one way that a facility like La Selva is invaluable, she says. “The long-term nature of our research means we simply could not have done it outside of a long-term, protected site like La Selva. And a lot of the things that we discovered could only have been done with the kinds of tools that are available at La Selva.”

These tools include the usual scientific amenities such as air-conditioned analytical laboratories, computers, and high-speed Internet connections. Also, surprising to visitors, who only perceive a confusing tangle of forest, La Selva is meticulously surveyed, with some 3,000 marker posts that enable researchers to locate and correlate their study subjects precisely.

A computerized geographical information system makes it possible to overlay data from one scientist—on tree species, for example—onto data from another on, say, ant populations. These correlations could yield important insights into the weave of the intricate web of tropical ecology, in which one organism may affect the survival of another. The presence of ants in a certain area, for example, could give insights into the ecology of vegetation, and vice versa.

Many visitors are also startled by another anomalous feature of La Selva—concrete sidewalks winding their way through the thick forests. The sidewalks have proved a highly useful component of La Selva’s scientific infrastructure, says Hartshorn, the OTS director. They enable scientists to pedal the station’s bicycles far into the forest depths to carry scientific equipment and collect data. And, oddly enough, the concrete sidewalks prove less damaging to the environment than the vegetation-crushing, muddy trails researchers had to slog in the past.

In the future, less visible forms of data collection will become available when the station installs a planned wireless computer network, enabling remote instruments to “report in” by themselves, thus making it unnecessary for a technician to retrieve data in the field. Hartshorn and his colleagues plan to use this technology to the fullest in such new research efforts as the Tropical Ecology Assessment and Monitoring (TEAM) project, which will involve years, possibly even decades, of detailed ecological measurements across La Selva and into the neighboring Braulio Carrillo National Park. “There are major and exciting scientific questions about how forest structure and composition change with elevation, and how animals might migrate across large regions,” says Hartshorn..