IN Mexico's southern state of Chiapas, Juan de la Cruz is discussing the precipitous drop in tourism since Indian rebels known as the Zapatistas began armed aggression against Mexican soldiers on New Year's Day. As a troop of endangered howler monkeys roar in the treetops, the conversation encompasses hardwood logging, slash-and-burn agriculture, and guerrilla demands for better living conditions among the region's 2 million peasant farmers.
``After the fighting began near San Cristobal de las Casas last January,'' Mr. de la Cruz recalls, foreigners stayed away. ``During the entire month, we had 15 visitors, or about 2 percent of normal.''
De la Cruz is a tour guide at Yaxchilan, an ancient Mayan city nearly encircled by a huge oxbow in the steamy Rio Usumacinta (Mayan for ``river of the sacred monkey'').
``This is a special place,'' de la Cruz says of the 1,200-year-old, tree-shrouded ruin. ``We must do all we can to preserve it.''
De la Cruz is worried not only about the dramatic drop in tourism, a big moneymaker in Chiapas, but also about Zapatista demands for rural electrification, paved roads, and peasant land grants. All are admirable goals, he allows, but their implementation could further endanger the vast but fragile Usumacinta watershed, the largest intact rain forest north of the Amazon.
``It's a very valid concern,'' agrees James Nations, a Mayan-speaking anthropologist who has spent many years in the area. ``Right now the Zapatistas are in a double bind. They want more land for the subsistence farmers [who are their main constituency], but they also want to save existing protected areas and respect the homelands of indigenous people.''
Mr. Nations, vice president of Mexican and Central American operations for the Washington, D.C.-based environmental organization Conservation International, warns that these and other political developments in the region could revive controversial plans for construction of a series of hydroelectric dams along the Usumacinta, which forms part of the border between Mexico and Guatemala. First proposed in the early 1960s and quickly denounced by prominent archaeologists, intellectuals, and ecologists, the dams would put dozens of Classic Maya sites - including much of Yaxchilan - under water. Simultaneously, they would irreversibly damage the surrounding Lacandon wilderness, which links with the adjacent Peten wilderness of northern Guatemala to form the largest pristine rain forest in Central America.
Current Mexican President Carlos Salinas de Gortari ``has promised publicly that there will be no dams built on the Usumacinta,'' says Arturo Gomez Pompa, chief adviser to President Salinas on tropical ecology. ``But we don't know if the next president of Mexico will do the same thing.''
Salinas's expected successor is Ernesto Zedillo Ponce de Leon, an economist technocrat who may feel immediate pressure to go ahead with the project in order to appease the Zapatistas as well as government officials in Guatemala.
Mexico's neighbor has been a reluctant partner in the binational venture, because it was until recently self-sufficient in electricity and does not control much of the eastern bank of the Usumacinta, a longtime stronghold of antigovernment guerrillas. In March, however, the Guatemalan National Revolutionary Unity (GNRU) reached a tentative peace agreement with representatives of President Ramiro de Leon Carpio. If the agreement holds, the government may be able to secure the area.
``A dam will never be built as long as we are here,'' insisted a 26-year-old GNRU guerrilla during a recent interview at Piedras Negras, a remote Mayan ruin on the Guatemalan side of the Usumacinta.
Representatives of the government-owned electric utilities of both countries declined comment on the dam proposal, but C. Jeffrey Wilkerson, Mexico-based director of the Institute for Cultural Ecology of the Tropics in Tampa, Fla., says that ``the dam project never dies, it just keeps getting revived. I fully expect that to happen again after the new Mexican president is inaugurated this fall.''
Meanwhile, the protective forests of the Lacandon are quickly being depleted by lumber companies, Mexico's state-owned oil monopoly, and farmers keen on exploiting its vast natural resources. Politicians are subdividing the borders of this wilderness, building roads and giving land away.
The most imminent threat to the area is the inexorable advance of settlers in a forest the size of Massachusetts that until recently had only a few thousand residents.
``My biggest fear is that the frontier will continue to be nibbled away while outsiders argue about how to protect it,'' says Victor Perera, a Guatemala-born author who has written extensively about the Usumacinta watershed. ``I think the Guatemalan government is a very long way from truly settling its differences with the rebels there, and both the Zapatistas and President Salinas have been saying the right things about protecting these treasures. In the meantime, however, encroachment continues.''
Researchers confirm that the estimated population of the Lacandon rain forest has jumped to at least 200,000 from only 12,000 in 1965. A healthy jungle that was 90 percent intact in 1965 has now been reduced to about 30 percent of its original size. Scientists point out that while it takes 400 years for such a rain forest to reach full maturity, its biodiversity can be disrupted forever when clear-cut for agriculture.
``The fragile and unique ecosystems surrounding the Usumacinta are players in a kaleidoscope of environmental drama that puts conservation, archaeology, politics, and economic development at odds,'' says Charlie Luthin, staff biologist and Central America coordinator for Lighthawk, a nonprofit research group active in the region.
To take a six-day raft trip down the Usumacinta is to see scenery that looks deceptively undisturbed. The spectacular river flows wide and deep through largely uncut jungle that remains home to far more animals than people. Along a stretch of 50 virtually inaccessible miles, from Yaxchilan to Boca del Cerro, fewer than 30 humans are seen along the riverbank. Instead, scarlet macaws and spider monkeys chatter in the lush canopy. Yet just beyond this green corridor, huge trucks loaded with chili peppers and construction materials rumble past cattle ranches and cornfields.
THE forest has been reduced substantially,'' says Moisas Morales, an archaeologist who lives by the Lacandon wilderness, ``but we have not yet reached the point of no return. Where there are no roads and treacherous waterways, there are still very few people.''
A key demand of the Zapatistas has been recognition of thousands of land-ownership claims made by peasants transplanted from the overcrowded highlands, who practice an age-old type of agriculture that replaces thick jungle with subsistence crops. This approach quickly exhausts the shallow topsoil of the rain forest and forces farmers to clear more land every few years.
``There is much that these newcomers can learn from the Lacandon Maya, who have farmed successfully for hundreds of years with minimal disruption of the forest ecosystem,'' says Will Hoffman, director of cultural studies for Na Bolom, an independent research center based in San Cristobal de las Casas. ``Environmental education is desperately needed because agriculture that may work in the highlands simply cannot succeed in the rain forest.''
Na Bolom and Conservation International are promoting agroforestry practices that maintain the forest's integrity while producing plenty of food. Since 1987, the government of Chiapas has refused almost all new logging-permit requests, and oil exploration in the region is now tightly controlled.
In the race to save the Usumacinta, Mr. Wilkerson says he believes worldwide attention needs to focus on the shrinking refuge along the river that is used by thousands of birds and large mammals to travel between the wilderness tracts of Chiapas and Guatemala. The area's density of many rare and endangered animals, including jaguars and howler monkeys, has increased as more creatures flee disrupted habitats.
``I propose that we establish international reserves that line up on both sides of the border to help retain not only the incredibly diverse flora and fauna of the region, but the priceless archaeological sites along the river,'' Wilkerson says. ``We're talking about protection of the core, the very center, of the only truly literate civilization in the ancient Americas and perhaps the most expressive in terms of art.''
``Things are suddenly more propitious for [damming and development] than they have been in years,'' says anthropologist Nations, who commends both rebels and politicians for proceeding cautiously along the Usumacinta. ``The situation deserves watching.''