A shoreline winds through the central Brazilian state of Mato Grosso. But rather than water, it’s the edge of a sea of nearly 400 billion trees. Here, the Amazon rainforest rubs up against the Cerrado, the world’s largest savanna.
It’s the meeting place of two distinct worlds. One’s a wet and verdant jungle. Relatively dry, the other is blanketed in wild grasses, shrubs and small trees. But no clear line marks the end of one and the start of the other. Instead, there’s a messy transition zone. It’s a jumble of vegetation that grows taller toward the rainforest. Over thousands of years, this boundary has ebbed and flowed.
Past shifts have been driven by natural changes in climate, says ecologist Beatriz Marimon in Brazil. She works at Mato Grosso State University in Nova Xavantina. Now, entering “in this formula is a new element,” she says: people. They’re trying to control the land.
About half a century ago, people started streaming into this region. They came in along new highways, Marimon notes. Quickly, they cleared forest for farmland and cattle ranches. Fifty years is a blink in the life span of this forest, which is nearly as old as the dinosaurs. But it’s plenty of time for people to remodel a landscape.
Today, scientists agree, the Amazon is in big trouble. Our activities and climate change are worsening the dry season. In some areas, it now lasts four to five weeks longer than in past decades. Fires have also become more fierce.
All of that is stressing the forest.
Many poorly understood factors affect the forest’s fate. These include human actions. There’s also climate change. And there’s the plants’ diverse biology and adaptations. Even the reach of underground water is poorly understood. What’s more, different parts of the forest may react to threats in different ways.
Ongoing research is clarifying…
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