Green Road Show.

Hato Dona Barbara clears an eco-track on the llanos.

FRANCISCO ESTRADA'S LATEST ECO-SCHEME SOUNDS LIKE AN oxymoron: 20 off-road vehicles clambering over a vast plain known for its threatened wildlife. Even the name of the event, 4x4 EcoAventura, seems contradictory. But the Venezuelan rancher and eavironmentalist swears there's a green goal.

The five-day event, slated for late April, is the latest in a roster of environmental projects at Estrada's ranch on the llanos, Venezuela's vast plains where cattle graze, families discuss the latest kidnappings around the dinner table and feuds may be settled by gunfire.

Estrada, 35, is the fifth generation to manage his family's 36,000-hectare spread, Hato Dona Barbara. Since 1989, when he took over daily operations of the ranch, which he calls a "won derful green laboratory," Estrada has invested exhaustive amounts of energy in projects to save range wildlife and foliage. He vows the 4x4 rally, punctuated with nature lectures and eco-outings, will stay in line with that goal.

"When my grandfather was here, there were more animals," Estrada explains, pointing an accusing finger at development, lax wildlife protection laws and fires set to clear land. Those wildfires pose the worst threat to slow-moving anteaters, turtles and capybaras, the world's largest rodents. Capybaras spend so much time in rivers that the Catholic Church once declared them fish--fair game on Lenten Fridays--and they were hunted nearly to extinction.

The Estrada ranch is one of many that blanket the llanos, but it carries an unusual distinction: It was nicknamed after Dona Barbara, one of Latin America's literary classics. And the moniker is more than coincidence. It was on the hato in 1927, during a visit by author Romulo Gallegos--Venezuela's future president--that Estrada's poet-grandfather told the story of Pancha Vasquez, a neighbor whom the llaneros claimed hexed her enemies, seduced men to snatch their land and skinned cows alive. When Gallegos wrote Dona Barbara, he based the title character on the rough-and-ready Vasquez.

The Estrada ranch, officially called Hato La Trinidad de Arauca, was saddled with the Dona Barbara name after a feverish Vasquez died there while waiting for a boat to take her down the Arauca River to a doctor. Ranchers barred her from a local cemetery, so Estrada's grandfather buried her on his land and marked the spot with a divi-divi tree.

Parallel lives. Estrada rejects any suggestion that he is a contemporary Santos Luzardo, the forward-thinking protagonist of Gallegos' novel. Still, there are striking similarities between the caraqueno, who didn't move to the ranch until after he graduated in computer science from the University of Texas at Austin, and Luzardo, the fictional modem-minded doctor who also returns to his family ranch.

In their green quest, Estrada and his family opened a ranch guest lodge in 1991 and started the Dona Barbara Ecological Foundation two years laer. The foundation mounts nature exhibits at the airport in San Fernando de Apure, is pushing for creation of a 20,000-hectare forest reserve and is keeping a census of local ospreys and anacondas.

Not all Dona Barbara's eco-projects have turned out as planned. An effort to relocate manatees to the ranch's river failed; they were sent instead to zoos, where one of the mammals died. An ecotourism push also has been disappointing.

In the 1990s, groups of North American students traveled to the Estrada ranch for wildlife studies, keeping an eye out for caiman, anteaters and freshwater dolphins. Bird-watchers on horseback searched for savanna hawks and Jabiru storks among the 300 species documented at the ranch. But no longer.

"Ecotourism has not been big business since [Hugo] Chavez became president. This past year we had about 12 good birders, eight students, 30 nature-oriented tourists and three film makers," Estrada says. "But the decline in visitors isn't just on the llanos, it's everywhere in Venezuela."

That decline is what prompted Estrada to embrace the controversial 4x4 event. Off-road vehicles will plow down a rough track that merges existing road with new areas cleared by machete. Drivers will be quizzed at check points about the wildlife they've spotted en route. They'll also take part in nature workshops, go on an anaconda search and see the howler monkeys on the ranch. Horns and music are banned on the EcoAventura, which Estrada says could become a regular event.

"One of the non-ecological aspects of this is the pollution from the motors. Believe me, if I could have only cars running on solar power, I would," Estrada says. "But remember, as ecological as we want to run the ranch, it is still a ranch and there are already some activities that are not ecologically sound. This is another way to make people think more about conservation and preservation."