The massive wildfires that have ripped through Brazil recently have not spared much of its tropical savannah, but green shoots are already emerging from the ashes there, a testament to the grasslands’ rare gift of fire resistance.
The Cerrado, the world’s most species-rich savanna, covers two million square kilometers (770,000 square miles) in central Brazil — about one-fifth of the country’s total land area.
In Brasilia National Park, on the outskirts of the nation’s capital, black soil and charred tree trunks are evidence of the ferocity of a fire that tore through 1,470 hectares (3,600 acres) in September.
At the time Brazil was in the grip of a record drought — the city of Brasilia had gone 169 days without rain — which shone a spotlight on the worst wildfire season in a decade, blamed at least in part by experts on climate change. .
But the Cerrado, less well-known than the neighboring Amazon and Pantanal wetlands, has great potential: over millions of years, it has been able to withstand fires and high temperatures.
– Upside Down Forest –
“The Cerrado is a reverse forest. We see only a small part of it because the whole forest is under our feet,” said Keiko Pellizzaro, an environmental analyst at the Chico Mendes Institute for Biodiversity Conservation, a government organization.
The Cerrado’s deep roots act as a “pump,” drawing up groundwater “even during the worst drought,” he said.
Meanwhile, above ground the thick bark of trees and fruit shells act as “thermal insulators,” said Isabel Schmidt, professor of ecology at the University of Brasilia.
Even when temperatures reach 800 centigrade (1,470 Fahrenheit), plants can survive “as if it were another hot day,” he said.
A month after the latest fires, the first rains saw grass and young plants begin to grow quickly, and new leaves sprouted from the burned trees in Brasilia National Park.
Even if it hadn’t rained, we would have seen the intensity,” said Pellizzaro.
“I’m amazed at its ability to regenerate,” said Priscila Erthal Risi, a 48-year-old volunteer involved in the Chico Mendes Institute’s plan to replant the reserve with native species such as donkey’s tail and Magonia pubescens trees. .
– Tested to the limit –
Brazilian police are still investigating the cause of the fire in Brasilia National Park.
Most wildfires in Brazil are started by farmers or agribusiness workers to clear land for grazing cattle or crops.
Schmidt said the Cerrado vegetation has been able to survive occasional fires caused by lightning during the rainy season.
But he warned that if severe droughts become more frequent the biome’s potential could be tested.
“The resistance of plants and animals to any kind of fire was developed over millions of years, but climate change happened over decades. No living thing can adapt quickly to that,” he said.
– The endangered ‘Cradle of water’ –
The Cerrado is important not only for the survival of the thousands of species that call it home but also for providing water for much of South America.
This so-called “cradle of waters” is home to the sources of some of the continent’s largest rivers and aquifers.
But its role as a continental spring is under threat.
With the rainy season starting later and later each year and the amount of rain falling by eight percent on average over the past three decades, the flow of the Cerrado’s rivers has decreased by 15 percent.
If wildfires become more common, Schmidt warned, “many fire-prone ecosystems,” including the Cerrado, “will not survive.”
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