You can only just hear the murmur of running water through Plinia Rodrigues' vegetable garden, but that tiny stream has a huge job: keeping alive Latin America's mammoth wetlands, known as the Pantanal.
Rodrigues, 63, shows off the thick stands of palms and other native plants crowding around the fish-filled, crystalline water. The garden in the tiny community of Piraputanga in the far west of Brazil, near the border of Bolivia, looks like a little slice of paradise.
It's also important, one of a myriad of similar streams rising from the lush landscape to feed the mighty Paraguay river, which in turn underpins the Pantanal.
But with industrialized agriculture encroaching deeper and deeper into former wilderness, that fragile water network nestled between Brazil, Paraguay and Bolivia is now under serious threat, experts say.
The problem is that even if the Pantanal itself is protected -- and Brazil's Congress is currently considering additional measures -- destruction of the sources upstream would be just as bad.
Rodrigues, who raises chickens, makes cheese and grows vegetables, says the undergrowth flourishing along her stream shows its good health. The plants help keep the banks in place, shielding the water and the life in it.
"We don't touch the river banks, so they're full of trees. We want to preserve what we have," she said, adding that she has only told a handful of other people about the hard-to-access spot where the stream is born.
But she's aware of the growing threat from deforestation, pesticides and industrial-scale planting of monocrops like soya.
Once, big fish swam here but they vanished when a nearby hydroelectric station blocked their path, she says.
"Everyone around here works with soya. Since that started, our trees haven't produced such good fruit," she said. "We grew papaya for the market but not any longer and the oranges have turned ugly."
- Natural treasure trove -
Covering 65,600 square miles (170,500 square kilometers), the Pantanal contains some 4,000 species of flora and fauna. But even though the Pantanal is Brazil's best preserved biosphere, that doesn't mean it isn't under pressure.
The Pantanal itself enjoys many legal protections and some 82 percent is untouched, the World Wildlife Fund says, but in the area where water rises, 55 percent of the territory has suffered deforestation.
"This region is at risk and if nothing is done to change this, we'll start seeing the collapse of the Pantanal during the coming years," said Julio Cesar Sampaio, WWF's coordinator for the Cerrado-Pantanal.
On the Pantanal, life is governed by the coming and going of the dry and rainy seasons. Between October and May, rain-swelled rivers spill and gradually flood 80 percent of the whole area, leaving only rich green islands.
At peak flooding, the Pantanal is a spectacular place for fishing and adventurous tourists. Birds, alligators, jaguars, monkeys and the mammoth green anaconda snake call this magical place home.
The Pantanal also plays an important role in controlling the climate, says Sergio Freitas, who studies the region at the University of Brasilia.
"The surface functions as a big mirror made of water, reflecting part of the heat back and making the climate more agreeable," he said.
It's not that humans can't coexist with the natural treasure house. Local cowboys, called "pantaneiros," move their herds in rhythm with the movement of the floods.
Freitas said ranchers have had a presence for more than 200 years without causing undue impact. The problem was the arrival in recent decades of intensive agriculture, reducing the topsoil and muddying the streams.
A better balance could still be achieved if the government applies incentives for producers to diversify and to steer away from current unsustainable practices, he said.