Scientists decry threats to Mexican wetland, an oasis in Chihuahuan Desert

Alfalfa plants sway under a thin veil of mist as towering irrigation equipment rolls above the crops, spraying the vast fields with water.

It's an important agricultural product in Mexico's northern state of Coahuila, grown there for hundreds of years. Rich in fiber and protein, it's used to feed livestock in Latin America's second-largest economy.

But alfalfa crops and other agricultural activities are also sapping dry the ancient oasis of Cuatro Cienegas, the most important wetland in the Chihuahuan Desert and a geological anomaly that scientists say can help them understand the origin of Earth, climate change and the chances of life on Mars.

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The 170 cactus-ringed pools contain important species of fish, snails, turtles, bacteria and unique living rock structures that offer important clues to life on Earth millions of years ago.

But since 1985, about 40% of surface pools and lagoons have been lost, the Mexican Institute of Water Technology estimated in a 2023 report. Water extractions from these bodies has increased at least 400% in 25 years, which the institute said is primarily due to an uptick in water concessions and water-reliant crops like alfalfa.

Scientists warn that the area could suffer catastrophic damage without a recovery plan.

Dairy farming in Mexico's main milk-producing region - the nearby city of Torreon - has since the beginning of the 20th century heavily relied on Cuatro Cienegas for water to feed wells used for as many as 14,825 acres of fodder crops each year, according to the Mexican Institute of Water Technology.

Ranches and crops run by large companies have diverted much of the supply, according to small-scale farmers like Mario Lopez, who has watched his own water access dwindle since he started growing alfalfa, corn and beans in 2008.

"We all have the right (to water) but for the small landowners, the pace has slowed down over the years," said Lopez. "When I started here, there was plenty of water, and now there isn't."

Lopez said his crops have scaled down to about six hectares due to the lack of water.

"Cuatro Cienegas is at risk of disappearing," said Valeria Souza, a researcher at the Institute of Ecology at Mexico's National Autonomous University who focuses on sustainable agriculture models for desert settings.

"It has survived two global freezes and five global extinctions, but it hasn't survived us 50 years," Souza said, adding that Cuatro Cienegas' unique characteristics reveal an understanding of whether other planets like Mars could be home to primitive life.

Arnulfo Ramirez, who lives in a nearby community, said he made a deal with a large dairy company to sell his land under the condition the company would ensure his water access - but recently the water has not come.

Instead, the community has to bring it in by truck, only if and when there is gasoline to do so.

"We bring water to bath, to wash the dishes, for the animals," Ramirez said. "It's an enormous expense."