- A study focusing on two prominent tree species in the Brazilian portion of the Gran Chaco biome found that degradation by industrial agribusiness, particularly soy growers, has put the biome’s genetic diversity at great risk. Decreasing genetic resilience could hamper the biome’s ability to adapt to climate change.
- The biggest Gran Chaco problem may be the lack of public awareness of its plight, and even its existence. Baseline plant and wildlife studies are limited, while Brazil, Argentina, Paraguay and Bolivia have done little to conserve the region, even as agribusiness continues to aggressively convert native vegetation to soy.
- By one estimate, the Gran Chaco in 2014 was losing native vegetation at a rate of 2.5 acres per minute. Another study predicted that more than half of all bird species and 30 percent of mammals found in the Gran Chaco today could be extinct in 10 to 25 years without conservation measures.
- The Brazilian study suggests that at least 42 separate natural remnants of the biome will need to be preserved for the next 300 to 3,000 years in order to maintain the minimum of 500 individuals within a species required to preserve genetic diversity for between 100 and 1,000 generations.
A study looking at the Brazilian portion of the Gran Chaco biome, has concluded that the ecosystem is at great risk of permanently losing its genetic diversity. As it exists today, the degraded biome – which is under extremely heavy pressure from industrial agribusiness – would require at least 300 years, or up to 3 000 years, to recover the range of genome variables necessary to maintain a healthy natural environment.
The study, published in the Ecology and Evolution journal, was conducted by scientists from a number of Brazilian institutions, including the University of Campinas (Unicamp), Federal University of Mato Grosso do Sul (UFMS), and the São Paulo Agency of Technology and Agro-Business.
The Gran Chaco is the largest dry forest in South America, encompassing an 800,000 square kilometer (308,882 square mile) area mostly in Argentina, Paraguay and Bolivia. Brazil claims a small portion of the biome, about 12,000 square kilometers (4,633 square miles) within the Porto Murtinho municipality of Mato Grosso do Sul state, bordering on the Pantanal wetlands.
Bounded on the west by the Andes, and on the east by the Brazilian Plateau, the biome is home to approximately 3,400 plant species; plus 500 bird, 150 mammal, and 220 reptile and amphibian species. Once covered in grassland, wet palm savanna, upland and dry thorn forest, Gran Chaco biodiversity has recently been devastated by soy producers, well backed by transnational commodities companies, including Bunge, ADM and Cargill.
While data concerning Gran Chaco deforestation rates is poor, estimates show that 2.5 acres of native vegetation were cut down per minute across the biome in 2014. According to Humboldt University research, more than half of all bird species and 30 percent of mammals found in the Chaco today could be extinct in 10 to 25 years if conservation measures are not quickly implemented.
Measuring the loss and potential recovery of genetic diversity
The study considered the rapid rate of deforestation in the Brazilian Gran Chaco alongside what remains. Data collected suggests that at least 42 separate natural remnants of the biome would need to be preserved for the next 300 to 3,000 years in order to maintain the minimum of 500 individuals in a species needed to preserve genetic diversity for between 100 and 1,000 generations.
For the purposes of the study, the research focused on the Prosopis, a genus of flowering plants in the pea family that includes subtropical and tropical spiny trees and shrubs. Individuals reach reproductive age at 3 years old. The authors chose two particular key Gran Chaco Prosopis species to illustrate how the forest as a whole has been functioning, and will need to function in future in order to maintain diversity.
One species studied was Prosopis rubriflora, a tree species ranging from five to six meters (16 to 19 feet) in height, with branches armed with spines and reduced linear leaflets. According to the study, the tree “is observed in the southern region in Mato Grosso do Sul [Brazil] and in northeastern Paraguay.… This species was considered endangered in Paraguay according to the IUCN 1997 list.”
The second species studied, Prosopis ruscifolia, has a height range of 5 to 12 meters (16 to 39 feet). “This species has larger distributions in the chaquenian areas [regions of arid low forest and savannas] of Bolivia, Paraguay, and Argentina, which are [also] associated with the chaquenian areas of Brazil.” The authors focused on P. ruscifolia because it is a valuable species for forest restoration in degraded semi-arid chaquenian areas.
Unicamp biologist and lead author, Fábio Alves told Mongabay that the research findings could – with some caveats – be applied not only to the Brazilian Gran Chaco, but to the Chaco biome in other countries. Among the regional variables are species population sizes, presence or absence of forest connectivity, and presence or absence of geographical barriers that can prevent the free flow of pollen and seeds. Specific contexts within various Gran Chaco countries also interfere in, or enhance, flora conservation, including economic activities, environmental laws, and the existence or not of agreements to limit deforestation. (Brazil, while it has an agreement to limit soy-related deforestation in the Amazon, has no such agreement in the Gran Chaco.)
Local genetics also help determine recovery potential, said Alves. “Some genes are very common between the studied populations, other are rarer. Neighboring countries’ plants can have similar genes to Brazilian ones, and they can also have exclusive genetics, and vice-versa.”
Agribusiness impacts
In the ten years between 1998 and 2008, Brazil’s 12,400 square kilometers of Gran Chaco native vegetation was reduced by one-third, according to Environment Ministry data. While that drastic loss should have triggered further monitoring, no official habitat loss data for the Brazilian portion of the biome has been produced since then.
Analysts say that rapid industrial agribusiness expansion out of the Pantanal region into the Gran Chaco is the main reason for escalating deforestation there. That expansion is driven by the soaring global industrial and consumer demand for soy – as animal feed, cooking oil, in baked goods, biodiesel, wood adhesives, environmentally-friendly solvents, lubricants, and other products. Brazilian soy is often destined for export to the European Union to feed chickens, and to China.
Júlio Sampaio, forest engineer and coordinator of the Cerrado-Pantanal program for the NGO, World Wildlife Fund (WWF) Brazil, believes that the major reason for the high deforestation rate in the Gran Chaco is the Brazilian government’s failure to officially recognize the biome or set conservation regulations there. “As the Chaco is in the middle of our Pantanal, it was forgotten by public policies. The ideal solution would be for it to be recognized as a whole natural group and with specific protection in Brazilian territory,” he said.
Genetic resilience vital on a fast-changing planet
Anete Pereira de Souza, a plant geneticist and leader of the Laboratory of Molecular Genetic Analysis at Unicamp, and a study coauthor, explained the importance of maintaining genetic diversity for centuries to come: “The easiest comparison is to think about consanguineous marriage [matrimony between individuals with close kinship]. If people related to each other have children, the odds of mutations are higher. The same happens to the plants,” she said. Scientists have found generally that when species populations fall below a certain threshold, genetic resilience seriously declines.
Maintaining genetic diversity is especially important in a rapidly warming world, where species need to be able to adapt quickly to changing climate conditions. Souza emphasized the importance of maintaining, and not losing, the diversity available today: “What causes diseases is the loss of variety. New fungi, low resistance, and lacking the capability of reacting to changes in temperature [and precipitation] are some of the consequences,” of diminished genetic diversity Souza affirmed.
According to Souza, there may be a major reason why the general public and national governments are not responding to Gran Chaco deforestation warnings by scientists: subtle changes in plant genetics are not as visible as changes in genetics with humans and other animals, so are harder to communicate. With birds, for instance, the existence of several individuals of the same species showing varying colors, or with longer or shorter beaks, can be easily understood as an expression of genetic diversity.
“Plants express different levels of transpiration, of resistance to exposure to sunlight, capability of retaining water, and of absorbing it faster,” Souza explained. These genetic differences proliferate in a population over millions of years, but aren’t obviously visible. But if temperatures rise quickly, or drought becomes more common, as is happening over portions of South America, these many genetic variations could be useful adaptions to new environmental conditions.
Fewer individuals, however, mean less genetic variation and less adaptability. Worse, when deforestation is uncontrolled as it is in the Gran Chaco, serious harm to genetic diversity can happen in a few days or months as trees are chain sawed down, with little or no awareness by those doing the cutting of what is being lost.
“It is almost impossible to reconstruct a diversity pool which is broken,” Souza said. However, the scientist remains optimistic, believing that time still remains in which to act decisively. “Our [study] results are alarming, but there still is a solution. We analyzed two [tree] species, and they can be used as a thermometer for all of the others.” According to the research, enough genetic diversity still exists to preserve the Gran Chaco pool, but immediate action is needed.
The Gran Chaco / European Union connection
Anahita Yousefi, campaign director for environmental NGO Mighty Earth, talked to Mongabay about the findings in its recent report The Avoidable Crisis, which focused on how the European meat industry stimulates deforestation in the Chaco.
Mighty Earth’s research has clearly demonstrated how the consumption of meat in Europe is linked to the production of South American soy for animal feed, and to deforestation, said Yousefi. According to the report, Europe imported 46.8 million tons of soy and soybean products in 2016 – 27.8 million tons of which came from Latin America. To grow that much soy, 8.8 million hectares (3.4 million square miles) of cropland are needed, a deforested area larger than Austria.
Unfortunately, “most people barely know that the Chaco is a biome. We still need to create the concept that this region exists,” said Yousefi. “The [conservation] work that was done with the Brazilian Amazon rainforest, for instance, should be replicated [in the Chaco] in order to reach the same results.
“If an agribusiness company respects environmental law in Brazil and advertises a zero deforestation policy because of the Amazon rainforest, the same should happen anywhere else in the world, Yousefi added. “But that is not what we saw even in neighboring countries, such as Argentina and Paraguay, when the subject is the Chaco.”
Cargill, one of the giant transnational commodity firms mentioned in Mighty Earth’s report, and a company very active in the Gran Chaco, replied to a Mongabay request for comment, but only wrote about its general activities in Brazil. In a statement, the company said: “Cargill recognizes that there is considerable urgency necessary to confront global challenges on climate and sustainability, including biodiversity loss. We are working with other players to stand for environments which are favorable, consistent and applicable that can be instituted by governments, civil society, producers, traders and clients in all of the supply chains with which we engage.
The company continued: “Cargill does not develop businesses with producers who break the law. For the Cerrado and the Brazilian Amazon rainforest, for instance, we have internal processes and controls to prevent acquisitions of embargoes areas and guarantee the sale of products originates only from proprieties which work by Brazilian law. When we identify a producer who goes against that, we cancel any transaction with that client.” It is worth noting that Cargill understood that this story was reporting on Gran Chaco deforestation, but made no reference to its activities there.
The forgotten biome
“The Brazilian share [of this unique landscape] is screaming for help,” Alves said, and so is the rest of the Chaco. But, the activist added, “While I was writing my thesis, there were no studies about genetic populations in other [Chaco] countries to compare and contrast with my own data,” demonstrating science’s long neglect of the region.
Likewise, during fieldwork, the research team learned that not even the citizens of Porto Murtinho – a municipality encircled by the biome – knew they lived within it. Even as, day-by-day, agribusiness chain saws and fires rapidly converted rich habitat to seemingly endless fields of soy.
Ultimately, the Gran Chaco – with its grasslands, wet palm savanna, and dry thorn forest; with its 3,400 plant species and 500 bird species – is a biome in grave danger of extinction before society understands its importance, or before people even realize it exists.
The Ministry of Environment and the Rural Association of Paraguay were both contacted by Mongabay, but did not reply to requests for comment. In Brazil, Mongabay reached out to the Temer administration and Bolsonaro administration; neither responded to requests for comment.
FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.
