Still time to save Brazil’s Cerrado, study shows, but it’s running out fast

Brazil’s Cerrado may not be a household name like the neighboring Amazon Rainforest, but this vast savanna biome is even more threatened and fragmented. A new study now shows there’s still a chance to save much of its rich biodiversity — but it also warns that the window of opportunity is closing fast.

A global biodiversity hotspot and the largest savanna in the world, the Cerrado is still often overlooked by local and international conservation initiatives. One recent example is the European Union’s law against deforestation-linked imports, approved this month by the European Parliament, which leaves the Cerrado out of its scope.

“Our research aimed to show not only which areas have a higher priority for preservation, but also how they have changed in the last few decades,” said study lead author João Paulo Vieira-Alencar, a Ph.D. candidate in ecology at the University of São Paulo. “By delaying the definition of conservation areas, we are losing our ability to preserve the endemic species that live there. We need more urgency.”

To define priority areas for conservation, the researchers mapped where in the Cerrado endemic terrestrial vertebrates are concentrated, using species records and the categories for extinction risk as determined by the IUCN, the global wildlife conservation authority. Areas with intense human activity were given lower priority, as these are considered harder to recover or convert into conservation areas.

So while the southern Cerrado would have been a good candidate for conservation if it hadn’t suffered human-induced land-use changes, the northern Cerrado currently offers more opportunities to preserve endemic species, according to the researchers. However, the pace of destruction there has now surpassed that seen in the south, adding more risks than ever to the last remaining big contiguous areas in the biome. Without immediate action by stakeholders, the authors warn, the northern region will eventually undergo fragmentation as well, and the level of conservation that could be achieved by acting now won’t be possible anymore.

To reach their conclusions, the authors considered various scenarios: one for a hypothetical Cerrado in a pristine state, and the other two with land-use data from 1985 and 2020 collected by the mapping initiative Mapbiomas. Then, for each case they mapped out the top-priority areas that would achieve protection for 17% of the Cerrado (applying the goal of the Aichi Biodiversity Targets). They then repeated the process, but with a more ambitious protection goal of 30%.

“While in the pristine scenario continuous priority areas were spread across the Cerrado, in the 1985 and 2020 scenarios they were concentrated in the northern portion of the region,” they wrote. These priority spots didn’t change very much between the 1985 and 2020 scenarios, but the distribution representation of endemic species decreased over time in those larger areas, another indication that protective action should be taken as soon as possible.

“It is not about which area is fine to lose, but a matter of where we are risking more. If we keep seeing a shrinking of contiguous areas, we end up missing more opportunities for preservation than if we protect the fragmented ones,” Vieira-Alencar told Mongabay. “Right now, the Cerrado suffers from deforestation at a pace that is two and a half times faster than the one seen in the Amazon Rainforest.”

More species with more diverse genes

Currently, when it comes to prioritizing what needs to be protected, there are two points of view, said Ricardo Machado, a professor at the University of Brasília who specializes in Cerrado conservation but wasn’t involved in the recent study.

“One interpretation is reactive, and the other proactive,” he told Mongabay. “There are people who believe the focus should be on the southern parts of the Cerrado, to save whatever still remains. Others would agree with the conclusions of the study, saying that we should preserve the northern parts before more fragmentation occurs there.”

Machado, who analyzed the study at Mongabay’s request, agreed that prioritizing the protection of the north would be cheaper and easier.

“You only need to keep what is still there and avoid further degradation,” he said, noting that trying to do something similar in the south would require hefty investments to recover already deforested areas, in a region with more intense human activity.

“Reversing fragmentation is not impossible, but it is difficult to do in the southern part because it is a very commercially active region, with crops that have changed the landscape many times and in various ways,” Vieira-Alencar said. “Once the area is restored, there comes a second effort which is also not easy: guaranteeing that the endemic species that once lived there actually settle in the region again.”

Another argument for prioritizing the northern portion of the biome centers on the genetic diversity of species, said Helga Correa Wiederhecker from WWF-Brasil, who wasn’t involved in the study but also analyzed its findings for Mongabay.

“There are at least two levels that one must consider regarding biodiversity: the absolute number of species that live in the region, as well as how variable is the genetic pool within the species,” Wiederhecker, who is also a professor of zoology at the Catholic University of Brasília, told Mongabay. “In larger areas like in the northern Cerrado, this diversity is enhanced, allowing the species to endure diseases and even some effects of climate change.”

The higher priority for conservation was placed on species the IUCN classifies as endangered (EN) and critically endangered (CR). However, one limitation the research faced was the large number of species with insufficient information to determine their conservation status, categorized as data deficient (DD). This could lead to biased results that fail to give enough importance to some of the vertebrates, since the DD classification can’t give an assessment of whether a species is really threatened; a persistent lack of data could in fact mean that there simply aren’t enough specimens remaining to be studied.

To compensate for this, the researchers gave a higher weight to DD species that haven’t been reclassified more than 10 years after they were first described, giving them a similar status to those classified as vulnerable (VU).

“For more recent species, it is usual to have deficient data, but if it’s been more than 10 years, we should expect to have additional information,” Vieira-Alencar said. “Recent studies have indicated that species that remain classified as DD are generally threatened, especially after a few years without new information. For this research, we used distribution data of species described up to January 2021. With an average of six new species described in the Cerrado every year, we are at a real risk of losing species that we don’t even know yet.”

In total, they analyzed 337 species, including threatened birds like the cock-tailed tyrant or galito (Alectrurus tricolor) and mammals like the giant anteater (Myrmecophaga tridactyla) as well as amphibians, snakes and lizards.

“The lack of information should not be a reason to delay action,” Wiederhecker said. “What we already have is enough to inform that we should start reversing current tendencies. Losing species means losing entire ecosystems, the way of life of the human population that interact with them, and even our climate stability.”

As the study notes, however, defining priority areas is just one step toward conservation of the Cerrado. Actually achieving its protection requires the combined efforts of various sectors of society, including policymakers, NGOs and the private sector, which holds nearly three-quarters of the land in the biome. And as things currently stand, there’s not enough incentive for agribusiness to conserve the swaths of the biome that they hold, experts say.

“As researchers, our greatest challenge is making this kind of study become public policy, informing the creation of new laws by Congress,” said Machado, who has been advocating for better regulation of the Cerrado for the past two decades. “It would be a shame if within five years someone runs similar research because more and newer data comes up, but in turn we lose more preserved areas that should have been prioritized.”

Citation:

Vieira-Alencar, J. P. S., Bolochio, B. E., Carmignotto, A. P., Sawaya, R. J., Silveira, L. F., Valdujo, P. H., … Nori, J. (2023). How habitat loss and fragmentation are reducing conservation opportunities for vertebrates in the most threatened savanna of the World. Perspectives in Ecology and Conservation. doi:10.1016/j.pecon.2023.02.004

Banner image: Image courtesy of Marizilda Cruppe/Greenpeace.

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