As Brazil's savanna is converted to farmland, less and less water is recycled and returned to the air where it forms new rain clouds. Photo by Fabio Maffei/Shutterstock
BURLINGTON, Vt., April 1 (UPI) -- A new study shows deforestation, already prevalent in the Amazon, has expanded southward into Brazil's Cerrado, a vast region of tropical savanna.
"This is the first study to show how intense the deforestation and agricultural expansion in the Cerrado has been in the past decade," Gillian Galford, an ecologist at the University of Vermont, said in a news release. "It's clearly a new hotspot for tropical deforestation."
In coordination with researchers at Brown University and the Woods Hole Research Center, Galford and her colleagues at Vermont used satellite imagery to plot the growth of agriculture in central Brazil.
Researchers analyzed images of a 45 million-hectare section of the Cerrado taken between 2003 and 2013. During that time period, researchers say farmland grew from 1.3 million hectares to 2.5 million hectares, and 75 percent of the expansion came at the expense of native flora.
The findings were published this week in the journal Global Change Biology.
Satellite data also revealed the shifting hydrology cycles in the region. As farmland replaces forest, the rate at which water is used and recycled changes.
During the wet season, water cycle shifts were negligible, but during the dry season, farmlands recycled 60 percent less water than native savanna.
Less water recycling can translate to less precipitation, a problem that could hurt agricultural production and could ultimately affect Cerrado's neighboring ecoregions.
"Timing of rains is a big deal," said study co-author Jack Mustard, an ecologist at Brown. "This is nearly all rain-fed agriculture in this region. If you start delaying the onset of rainfall, that has implications for what you can grow."
"Half of the rainfall in the Amazon is recycled water," added lead author Stephanie Spera, also at Brown. "So a decrease in moisture in those air masses could cause a decrease in rainfall there, too."
Agricultural expansion in Brazil isn't slowing down, but the new research did identify strategies for more sustainable farming. Farmers that practiced "double cropping" -- growing two crops in the same field during the same growing season -- helps reduce the water recycling deficit.
In 2003, only 2 percent of farmland featured double cropping. That number jumped to 26 percent in 2013.