(AFP) – Plants growing back on charred ground: this spectacle illustrates the resilience of the Cerrado, the Brazilian savannah, however increasingly put to the test by fires.
In Brasilia National Park, the ground and charred trunks bear witness to the passage of a fire which reached 1,470 hectares in September in this biodiversity sanctuary.
The Brazilian capital was then experiencing a historic drought, going 169 days without receiving a single drop of rain, a record.
This is far from an isolated case. The year 2024 is already the worst in more than a decade in terms of vegetation fires, with more than 240,000 outbreaks recorded in the country.
Mostly caused by human action, these fires are spreading more easily this year due to extreme drought linked, according to experts, to climate change.
But the Cerrado, the savannah richest in biodiversity in the world, located in the southeast of the Amazon, is equipped with natural mechanisms that allow it to resist flames and high temperatures.
– “Head down” –
“The Cerrado is a forest that is upside down, we see very little of this forest because it is under our feet,” Keiko Pellizzaro, head of Brazilian national parks at the Chico Mendes Institute of Conservation, explains to AFP. of Biodiversity (ICMBio), a public body.
The soil is “like a sponge”, and beneath the earth a system of very deep roots makes it possible to “pump” groundwater, “even during extreme drought”.
On the surface, the thick bark of trees and walnut shells act as “thermal insulation,” according to Isabel Schmidt, professor of ecology at the University of Brasilia.
Vegetation can thus survive even if the temperature reaches 800ºC due to the flames.
– Regeneration –
Barely a month after the fires, after the first rains, grasses and small plants began to grow back between the stumps and charred trees found leaves again in Brasilia National Park, a reserve of more than 40,000 hectares.
“Even if it hadn’t rained, we would have seen a certain resilience,” assures Keiko Pellizzaro.
“I am amazed by this capacity for regeneration,” confides Priscila Erthal Risi, a 48-year-old volunteer who is participating in an ICMBio operation to regreen the park.
She sows seeds of native plants such as donkey tail, or trees such as tingui (Magonia pubescens).
The fire at Brasilia National Park is under police investigation. As with most vegetation fires in Brazil, suspicions relate to the start of the fire of criminal origin, to make way for fields or pastures.
The Cerrado's vegetation is used to regenerating after sporadic fires caused by lightning, explains Isabel Schmidt.
But, she warns, if extreme drought becomes more frequent, it could challenge the limits of the resilience of this biome (a large geographic area sharing a similar climate, fauna and flora).
“The resistance of plants and animals to flames has been acquired over millions of years, but climate change is observed over decades. No living organism can adapt so quickly,” he laments. -She.
– In danger –
Less famous than the Amazon or the Pantanal, the neighboring biomes, the Cerrado is nicknamed the “cradle of waters” because its sources feed important South American rivers and aquifers.
But it is in danger: according to scientists, the rainy season is starting later and later and precipitation has fallen by 8% on average over the last three decades, reducing river flow by 15%.
Isabel Schmidt recommends controlled fires to clean vegetation and thus limit the spread of unwanted outbreaks.
If the situation continues to worsen, “a large number of more sensitive ecosystems risk no longer regenerating,” she warns.
