- New study addresses the effects of fires on biodiversity loss in the world’s largest forest during the last two decades.
- Researchers measured the impacts on the habitats of 14,000 species of plants and animals, finding that 93 to 95% suffered some consequence of the fires.
- Primates were the most affected, as they depend on trees for movement, food and shelter. Rare and endemic species with restricted habitats suffered the strongest impacts.
- The study assessed two decades of fires between 2001 and 2019 and confirmed the impact of environmental policies on deforestation cycles in the Amazon; law enforcement was concluded to have direct impact on the extent and volume of fires.
Since 2019, deforestation and fires have caused the Brazilian Amazon to lose about 10,000 square kilometers of forest cover per year – a high and alarming increase over the previous decade, when the annual reduction in forest area was close to 6,500 square kilometers, according to data from Brazil’s National Institute for Space Research (INPE).
However, until very recently, experts had measured only the vegetation in areas destroyed; never had the biodiversity loss caused by fires been assessed. A new scientific study published in Nature – “How deregulation, drought and increasing fire impact Amazonian biodiversity” – translates this impact into numbers: to a greater or lesser extent, 93 to 95% of 14,000 species of plants and animals have already suffered some kind of consequence of the Amazon’s fires.
The study, which involved researchers from universities and institutions in the U.S., Brazil and the Netherlands, analyzed data on the distribution of fires in the Amazon between 2001 and 2019, when the region saw record rates of major fires, despite high rainfall.
“At the time, the fires attracted a lot of international media attention, and we were interested in better understanding their consequences, where they had happened, and which areas were occupied by fauna and flora,” says biologist Mathias Pires, a professor and researcher at the Department of Animal Biology at the State University of Campinas (Unicamp).
Using satellite images, the researchers compared the areas affected by fires – from 103,079 to 189,755 square kilometers of the Amazon rainforest – with habitats of 11,514 plant species and 3,079 animals (including vertebrates, birds and mammals).
“We were surprised to find that the habitats of most plant and animal species had already been affected by fires and that this impact continued to increase over time, despite the best conservation efforts,” says Brian Enquist, professor of ecology and evolutionary biology at the University of Arizona and a lead author of the article.
Primates suffered the worst impacts
The analysis indicated that, for some species, more than 60% of their habitat had been burned at some point in the last two decades. For the majority of the Amazonian plants and animals, though, the impacted areas represent least than 10% of their habitar range. While this sounds like a small percentage, a little bit of habitat loss in the Amazon can already be consequential for species survival. “Any lost habitat is already too much,” says Danilo Neves, professor of ecology at the Institute of Biological Sciences of the Federal University of Minas Gerais (UFMG).
He explains that some groups of rare and threatened species have restricted distribution in the Amazon, such as the white-cheeked spider monkey (Ateles marginatus), which is endemic to Brazil and classified as endangered on the Red List of the International Union for the Conservation of Nature (IUCN), meaning that its probability of extinction is high.
“That species depends a lot on the standing forest,” says Pires. “Monkeys need trees for displacement, food and shelter. They hardly ever move or feed on the ground.”
The white-cheeked spider monkey had 5% of its range affected by fire. “Five percent of the range impacted in 20 years is a lot,” he says. “What will happen in another 20 years, or 50…? We need to consider that, from a biological point of view, that’s very fast loss of habitat.”
Pires stresses that primates are under the highest threat from Amazonian fires. To draw a parallel with another animal species, he uses a bird – the hoatzin (Opisthocomus hoazin). Classified as threatened on the IUCN list, it ends up being relatively less affected by forest fires since its habitat range can cover virtually the entire Amazon.
As for plants, which, unlike animals, cannot escape the flames, the situation is even more disturbing. The tree species Allantoma kuhlmannii had about 35% of its range impacted by fire.
Unlike the Cerrado, where plants are more resistant to fire and drought, Amazon vegetation is adapted to closed environments and moist soil; when the flames end, the plants can hardly recover, and that part of their habitat may be lost forever.
Since the study focused on measuring the number of species impacted by fire, it did not look for any visible change in animals’ behavior or habitat.
“Given the scale, scope and growing impact of fires across the Amazon, it’s likely that animal populations have already been affected by habitat loss and the opening of more remote areas to hunting,” Enquist believes.
Less enforcement, more fires
By overlaying data on fires with the habitat ranges of flora and fauna, the researchers noticed three fire cycles in the Amazon, which are directly associated with distinct political contexts in Brazil.
In 2001 to 2008, lack of strict environmental enforcement in the country served as fuel for more frequent fires in larger areas. In the following period, 2009 to 2018, enforcement policies managed to curb deforestation. However, in 2016, even though Brazil’s environment protection laws were praised globally, enforcement loosened, and deforestation started to rise again in the Amazon.
In 2019, when current president Jair Bolsonaro took office, the situation worsened. High forest destruction rates continued, driven by federal government rhetoric in favor of mining, against demarcation of indigenous lands, and critical of the work of non-governmental organizations.
“Our results clearly show that forest protection policies had a dramatic effect on the rate of impact of fires and on Amazonian biodiversity,” stresses Enquist.
The international survey points out that, in recent years, there have been fires in more central parts of the Amazon, including areas close to rivers, which is a new trend. “Fire consolidates deforestation. Deforested areas can regenerate, but that would require much more time and investment after the fires,” says Neves.
Risk of biodiversity loss and more extinctions
Scientists worldwide have made clear what needs to be done to restore the Amazon, that being to reduce deforestation, prevent fires and, consequently, protect the habitats of millions of plant and animal species. The formula to do so exists and has been used in the past: stronger commitment to environmentalism, effective law enforcement, forest monitoring, and support for environmental agencies.
Brazilian researchers Danilo Neves and Mathias Pires have no doubt that this is the only way to reverse the current scenario of habitat devastation and loss. “We know what to do. We have already solved the problem before,” says Pires.
The evidence is indisputable. Forest protection policies have a dramatic effect on fires and their impact on Amazonian biodiversity. But, if nothing is done, what can we expect from the future of life in this biome?
“We risk reducing and potentially losing large fractions of biodiversity, which is nature’s capital that gives resilience to climate change, and important ecosystem services that the Amazon provides to humanity,” says Enquist. “If nothing changes, we will see continued habitat degradation for most Amazonian species. As fire and deforestation now move into the heart of the Amazon and regions that are home to species inhabiting smaller geographic areas, the risk of extinction increases dramatically for thousands of forms of life.”
This story was produced in collaboration with Landscape News to raise awareness of topics relevant to the upcoming Global Landscapes Forum’s Amazonia Digital Conference: The Tipping Point (September 21-23, 2021). Join here.
Banner image: Burning area near the Jacundá National Forest, in Rondônia state. Image by Bruno Kelly.