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There are about 30 species of vibrantly colored Amazon parrots that soar through the skies of Mexico, the Caribbean and South America. But a new fluffy family member may soon be added to the Amazona genus. As Ian Sample reports for the Guardian, a team of researchers believes they have discovered a never-before-seen species of the parrot on Mexico’s Yucatán Peninsula.
Miguel Gómez Garza, an ornithologist at the Autonomous University of Nuevo León, first spotted the birds in 2014. He was conducting research in the Yucatán when he heard an unusual call coming from the trees. Garza observed a group of parrots that resembled the Amazon, but the noise they were making was short, sharp and hawk-like—very different from the cries of other parrots in the area.
“I could not believe it,” Garza told Sample. “The different noise belonged to a different parrot.”
The newly discovered bird also displayed unique markings, which are described in a study published recently in the journal PeerJ. Fiery red plumage sprouts from the parrot’s forehead. Its crown is green and its wing feathers are bright blue, leading Garza and a team of researchers to call the parrot the “Blue-winged Amazon.” More formally, the parrot has been dubbed Amazona gomezgarzai in Garza’s honor.
According to a press release, the new parrot lives in flocks of less than 12 individuals. Mated pairs tend to stay together with their offspring, and are discernible within the larger group. The Blue-winged Amazon likes to munch on fruit, flowers and seeds, and it is possible that the parrot mimics the cry of a hawk to scare other birds away from tasty snacks, Sample reports.
To study the parrots in close proximity, Garza received permission from Mexican authorities to capture a male and female member of the species. With the help of Tony Silva, an independent bird researcher in Florida, and Pawel Mackiewicz, a geneticist at the University of Wroclaw in Poland, he measured the birds and took samples of mitochondrial DNA—genetic material that is passed from mother to child. The tests suggest that the new species is relatively young, evolving from the white-fronted Amazona albifrons about 120,000 years ago.
But not all experts are convinced the bird is a new species. John Bates, an associate curator at the Field Museum in Chicago, tells Traci Watson for National Geographic that the genes studied by the researchers are “very weak” for species identification.
“I'd personally like to see more genetic work before making any conclusions about this,” he tells Watson. Responding to this criticism, Mackiewicz says that the team looked at the same genes as other parrot studies.
If the Blue-winged Amazon is in fact a distinct species, it is also a rare one. Researchers estimate that only 100 blue-winged Amazons exist in the wild, and they fear that habitat destruction and the illegal pet trade threaten the birds’ survival. Consequently, the authors of the study argue, implementing a conservation program for this unique parrot should be a top priority.
“Save the Rainforest!”—the rallying cry of environmentalists for decades—ultimately failed. Despite a slight slowdown in deforestation in the 1990s and 2000s, says Slate, trees are now dropping at around the same rate as they were at their peak in the 1980s. Worse still, the Guardian reported this week that the problem seems to be getting worse:
Satellite data indicates a 190% surge in land clearance in August and September compared with the same period last year as loggers and farmers exploit loopholes in regulations that are designed to protect the world’s largest forest.
For years, says the Guardian, Amazon deforestation was slowing down. Last year, that trend started to turn around, and the huge jump this year show that uptick wasn't just a fluke.
Figures released by Imazon, a Brazilian nonprofit research organisation, show that 402 square kilometres – more than six times the area of the island of Manhattan – was cleared in September.
The recent resurgence in deforestation is a much more serious issue than you might think.
Scientific research has shown that the rainforest itself affects the weather in the region. The trees affect how water moves through the ecosystem, how the wind blows and where rain falls. Cutting the trees down and turning the area into farmland or grassland changes this relationship. The very existence of the rainforest helps to create the weather that maintains the rainforest, and cutting down the trees destabilizes this balance.
According to a recent study, if loggers cut down just 10 percent of the existing rainforest, big chunks of the Amazon could collapse, transforming from rainforest into grassland. Roughly 40 percent of the Amazon Rainforest is protected area, but these scientists say we need to protect at least 90 percent of it.
Rapid deforestation, or even this type of dire ecosystem shift, would have huge consequences for the rest of the planet. Among other things, Amazon deforestation could decrease rainfall in the U.S. West, a region already suffering from a historic drought.
The Amazon is arguably the most biodiverse place on Earth. The 4,000-mile river that runs from the Andes to the Atlantic Ocean is surrounded by a two and a half million square mile river basin, roughly the size of Australia, and claims some 2.6 million species with many more still unknown to science. It turns out that as vast as the region is now, the modern Amazon rain forest ecosystem represents but a fragment of the diversity of habitat and wildlife that existed between ten and 18 million years ago when it was seasonally flooded with ocean water from the Carribbean Sea.
Carlos Jaramillo, a staff scientist at the Smithsonian Tropical Research Institute and lead author of a new research paper published this week in Science Advances has concluded that the Amazon once possessed a vast inland sea surrounded by seasonally flooded land. The Caribbean waters penetrated deep into the west Amazon with the salty ocean water flooding the forests during raining seasons and receding from some areas during the dry seasons.
Previously, the Amazonia region of South America was thought of as having been dry land throughout its history. Jaramillo, who was initially skeptical of the idea, was able to piece together this portrait of a lost ecosystem by digging up fossils. He took deep core samples of rock and soil and studied exposed outcroppings at many locations around today's Amazon.
“I thought it was impossible,” Jaramillo said as he stood in his spacious Panama City office beside a long table covered in books, printed scientific papers and fossils of bones and plants waiting to be categorized. “It's hard to imagine that you could have the Caribbean ocean in the west Amazon. . . . it's too far away. The Amazonian rains a lot so you have a lot of sediments. It's very hard for the ocean to gain terrain through the rivers.”
But he says, if you could travel back in time, 18 million years ago, and fly a hundred feet above the ground, you would experience a world where land and water intermingled across a vast region. He walked a few paces to a computer screen and pressed 'play' to reveal a digitized model showing the shifting range of the lost sea over time.
Watch this video in the original article
“During the dry season you will see permanent rivers and maybe hundreds of isolated lakes of different sizes,” Jaramillo says. “And in between the lakes you will see forests. Then [during] the rainy season many of those rivers will flood the whole landscape. Maybe a few places will be dry. And the next dry season, the lakes and rivers will shift position. That continues, but on a continental scale.”
The theory that the Amazon Sea once existed is not new, says Donald R. Prothero, a geologist specializing in the history of South America. It dates back at least to the 1950s, but evidence for it had been weak until now.
"I think that the key thing here is that [the theory] was [previously] all based on very limited outcrops," Prothero says. "It's hard to get anything good in the Amazon because it is so heavily grown over with plant matter. That is what is crucial. The fact that they have a core sample now that gives a continuous record of the whole Miocene, based on what they said in the paper."
In spite of his initial skepticism, Jaramillo found fossils that could only be explained by an inland sea that persisted and moved for millions of years. Fossils of mantis shrimp, shark teeth, dinoflagellates and saline-loving bacteria were discovered deep beneath the rain forest. As he was able to date the samples, a picture began to emerge. This was not a one-time flood. It was a complex, long-term ecosystem.Samples were taken from exposed outcroppings along river banks, such as the Soliõmes River in Brazil. (Carlos D'Apolito)
Amazonia of the past was dominated by large crocodilians at the top of the food web, says Jaramillo, who describes a world in which the creatures in a variety of shapes and with lifestyles unlike modern crocodilians swam and crawled across Amazonia.
“There were crocodiles eating only shells, they had a face that looked like a duck,” Jaramillo says of the huge, 56-foot-long purussaurs, the largest crocodyliformes that ever lived on Earth. So tall that standing face-to-face with a fully grown purussaur, he says, you would probably find yourself staring directly into its eyes. They were the largest reptiles that the Earth has witnessed since the end of the non-bird dinosaurs.
Turtles of different sizes and mammals, including the diverse family of toxodontids, were also present. Many types of fish and huge numbers of molluscs represented a large part of the total biomass.Studying deep core samples like these, Jaramillo pieced together a portrait of a lost ecosystem. (Vladimir Zapata and Carlos D'Apolito)
Jaramillo says that his paper shows the emergence and eventual demise of the Amazon sea were both probably caused by the influence of the young Andes mountains.
As the Andes thrust upward from the Earth's crust, “they created a depression in the Amazon because of the weight of the mountains going higher and higher,” he says. “As the mountains develop and move higher and higher. This wave of vibration that is produced in the continent because of the uplift shifts around.”
When the Amazon was pushed downward by tectonic forces, water was able to easily intrude from the ocean. But later the dynamic of forces from the Andes began to change.
“Around 10 million years ago it shifted away from Amazonia. The whole region, instead of going down, it started to shift up,” Jaramillo says.
Jaramillo shook his head emphatically when asked if there is any modern equivalent to the lost ecosystem described in the paper. “There is not a place on the planet that you could go to and see something like that on the scale of what we see in the Amazonia,” he says. “Maybe a few places in the Congo but never to the same extent. It's not really a swamp, it's not really a lake.”
Prothero believes that the evidence presented in Jaramillo's paper is compelling enough to rewrite history. “This radically throws out a lot of what was said about the Amazon in the past,” Prothero says. “It's coming from indisputable marine beds.”
This is not Jaramillo's first major discovery. In 2009 he was part of a team of scientists that discovered titanoboa, a species of snake that lived in South America about 60 million years ago, shortly after the demise of the dinosaurs.
Titanoboa was long gone by the time the Amazon sea emerged about 18.4 million years ago during the Miocene epoch. At that time, the age of mammals was well underway. Earth's continents looked very similar to the modern globe. Early horses roamed North America. Modern-looking crows and ducks had emerged. South America was still not connected to North America, so it harbored unique animals that had evolved in relative isolation from the rest of the world.
Like paleontologists, who dissolve the hard, rock-like structures of dinosaur bones with a mild acid to check for blood vessels and proteins in soft tissue, Jaramillo says that will be his next step. “The turtle shells usually have proteins preserved,” he says.
Editor's Note May 8, 2017: This article originally misstated that the Amazon river runs from the Andes to the Atlantic Ocean. It runs to the Caribbean.
A new study finds that the Amazon rainforest’s “ghost dog” has haunts across five countries.
The hound in question is the short-eared dog, a solitary canine specially adapted to live in the South American jungle. The study, published in the journal Royal Society Open Science, found that short-eared dogs have been spotted primarily in Brazil and Peru, but they were also found in Bolivia, Colombia and Ecuador. But almost a third of short-eared dog habitat could be lost by 2027.
The species is “one of the least studied dogs worldwide,” University of California, Davis ecologist Daniel Rocha tells Cara Giaimo at the New York Times. “If we don’t know what we’re losing, it’s really hard to care.”
The short-eared dog is different from many wild canines because it doesn’t live in packs, explains Mongabay’s Romi Castagnino. The creatures are extremely shy, preferring to live in swamp forests, bamboo stands and cloud forests that haven’t been disturbed by people. They’re recognizable by their small ears, dark gray or rusty coloring, and fluffy, foxlike tails.
The dogs also have webbed toes which make them strong swimmers, like the ever-popular Labrador retrievers. But short-eared dogs are not in the same genus as domestic dogs (Canis familiaris) or gray wolves (Canis lupus). Instead, short-eared dogs (Atelocynus microtis) are the only members of their own genus.
Short-eared dogs are so secretive that local residents and researchers alike rarely see them in the wild. Rocha tells the Times that throughout the years-long research project, he never saw one. Even University of East Anglia ecologist Carlos Peres, who has worked in the Amazon for almost 40 years, tells the New York Times that his longest encounter with a short-eared dog was brief.
He saw one for about 20 seconds when it chased a rat into a hollow log. Researchers know from scat samples that the dogs probably eat a mix of small mammals, fish, and even fruit.
The new study pieces together sightings from camera traps across the Amazon rainforest, usually brief encounters that were “bycatch” during unrelated research projects, Rocha tells the New York Times.
In 2014, for example, conservation biologist Lary Reeves set up a GoPro camera near a carcass in the jungle of Peru, hoping to catch a glimpse of the king vultures he’d heard were feeding on it. But as National Geographic’s Nadia Drake reported at the time, a short-eared dog stopped in front of the camera only about 20 minutes after it was set up.
Usually they avoid cameras, probably because of the blinking lights and human smells. In 2017, researchers got their first glimpse of short-eared dogs’ puppies on camera.
“This is totally amazing. It’s a great opportunity to study this species, a unique opportunity to study the maternal care of the babies, how the babies disperse,” Leite-Pitman told Nadia Drake at National Geographic of the five pups caught on camera. “What are their survival chances? How many of them will survive? None of these questions are answered for this species.”
The short-eared dog is currently listed as near threatened on the IUCN Red List, but the new study suggests that they should be considered vulnerable instead, as Inverse reports. Thirty percent of the dogs’ habitat could be gone or severely damaged by 2027 because of human activities like logging.
The loss of habitat would significantly impact an animal that relies on undisturbed range, but Rocha also points out that there are many other, less familiar critters that are facing the same threat. With so much left to learn about a cousin of man’s best friend, Rocha tells the New York Times, “imagine how much we don’t know about less charismatic species.”
This new research has revealed that in areas considered unsuitable for farming today, "pre-Columbian farmers constructed thousands of raised fields in the seasonally flooded coastal savannas of the Guianas.
The post Amazon farmers who vanished centuries ago were remarkably innovative appeared first on Smithsonian Insider.
Forest loss in the Amazon continues, but over the last decade, it has largely been slowing down in Brazil. That may seem like a win for the region’s unique biodiversity, but simply halting deforestation won’t be enough to stem the loss in species, a new study in Nature contends. That’s because human disturbance—such as wildfires and selective logging, which can continue even when clearcutting stops—have an outsized impact on biodiversity loss, the study finds.
Brazil has been able to slow its once-rampant deforestation with a Forest Code that says landowners must preserve 80 percent of their land as forest cover. But those forested areas still face threats from humans; roads and selective logging are allowed in them, and wildfires can easily spread from the agricultural areas where they are deliberately started.
Previous studies have looked at the effects of such disturbances on biodiversity singly, but “those things don’t happen in isolation,” notes Toby Gardner, a sustainability scientist with the Stockholm Environment Institute and the International Institute for Sustainability in Brazil. Many of these disturbances feed off one another. A logged forest is more likely to burn, for example, and if land burns once, it’s more likely to burn again. Without studying all of these disturbances together, their full impacts can’t be known.
So Gardner and an international group of researchers created a network to assess biodiversity across 36 landscapes in the Brazilian state of Pará, which is home to about a quarter of the Amazon. The scientists looked at three groups of species—trees, birds and dung beetles (the last group is easy to survey, Garner notes, in addition to being “excellent indicators of environmental change”)—and compared diversity in deforested areas with areas that had been disturbed.
Losing 20 percent of forest cover in an area resulted in a 39 to 54 percent loss of conservation value, a measure of species richness, the scientists calculated. That is two to nearly three times what might be expected from deforestation alone, and the scientists determined that human disturbances cause the additional loss. Worse, rare species that may be found nowhere else in the world are often the ones that are most affected by these disturbances, the team found.
Extrapolating from the study areas to the entire state, the researchers calculated that the biodiversity loss from human disturbance was equivalent to clearcutting as much as 139,000 square kilometers of pristine forest, an area of land the size of North Carolina.Even controlled wildfires can take a toll on Amazonian biodiversity. (Adam Ronan)
Limiting deforestation is an important step for preserving the biodiversity of tropical forests, Gardner says, but these results show that it’s not enough. “The forests that remain, they’re a shadow—functionally, biologically, ecologically—of the forests that once stood there,” he says. In Pará, he notes, there are very few, if any, forests left that have not been impacted in some way by either deforestation or human disturbance.
David Edwards, a conservation scientist at the University of Sheffield who wrote an accompanying commentary in Nature, agrees with Gardner’s group. “Just focusing on stopping deforestation is not enough. We must also focus on preservation of forest quality,” he says.
There is no easy solution, though. Halting the slow decline of biodiversity would require an integrated approach that includes better land use planning and more enforcement of existing laws against illegal logging, hunting and use of fire, Edwards says—a process that would be expensive and time-consuming. Without that, species are at risk of disappearing, especially those that are found in only small areas of the Amazon.
“I’m sure [the new findings] won’t be surprising to conservation biologists and ecologists because forest cover is not a very good measure of all the complex processes happening inside the forest,” says Tremaine Gregory, a primatologist with the Smithsonian Conservation Biology Institute who has been studying how animals respond to hydrocarbon exploration in the Peruvian Amazon. “When you work in the tropical forest…you can see what an interconnected web it is.”
Gregory and her colleagues are trying to find solutions to minimize the impact of human presence in the Amazon, such as making sure that monkeys and other arboreal animals have paths through the trees that let them cross natural gas lines. The new study, she says, shows that such research has value.
“We are continuing to have a major distorted influence on our ecosystem and our planet,” she says. But if human activities have to happen in certain areas, “it should be done in the least impactful way possible. And we can only know what those low-impact methods are if we carry out robust scientific studies to understand them.”
The impacts seen in the Brazilian Amazon may be indicative of problems going on elsewhere in the world, Gardner says. The types of disturbance may vary from place to place, “but the problem is general.” And the most heavily disturbed forests, such as the ones found in the eastern United States, he says, are “all shadows of what they once were.”
Brazil is investigating reports that a group of miners may have killed 10 members of an “uncontacted” tribe of Amazon natives, chopping up their remains and tossing them in a river, reports Shasta Darlington at The New York Times.
The allegations of the massacre might have gone unnoticed except the miners were heard bragging about the slaughter, which took place last month, at a nearby bar in Amazonas state, close to the border with Colombia. Darlington reports that witnesses claim the miners also carried a hand-carved paddle and small food bag which they said they took from the tribe members.
The killings have not been confirmed, but Funai, Brazil’s agency for indigenous affairs is currently conducting an investigation. “We are following up, but the territories are big and access is limited,” Pablo Luz de Beltrand, the prosecutor in the case, tells Darlington. “These tribes are uncontacted — even Funai has only sporadic information about them. So it’s difficult work that requires all government departments working together.”
According to Dom Phillips at the Guardian, the unconfirmed killings took place in the Javari Valley, near the border with Peru. That remote area is home to 20 of Brazils 103 “uncontacted” tribes, which are groups of people with no peaceful contact or relationships with mainstream societies. According to Survival International, these groups are under threat from loggers, miners and governments interested in acquiring the resources on their lands, often subject to removal, forced contact, disease and genocide.
In Brazil, the government has recently reduced its protections of so-called uncontacted tribes and forest-dependent tribes, cutting the Funai budget almost in half this year, which led to the closing of three bases in the Javari Valley used to monitor and protect indigenous populations, reports Darlington. The government has also proposed reducing the size of protected areas of the Amazon rain forest and opening protected areas to mining and logging.
“If the investigation confirms the reports, it will be yet another genocidal massacre resulting directly from the Brazilian government’s failure to protect isolated tribes — something that is guaranteed in the Constitution,” Sarah Shenker, a senior campaigner with Survival International, tells Darlington.
CBS News reports that some of the miners allegedly involved in the incident have since been detained. But sorting out the complete story may be difficult. Cleve R. Wootson Jr. at The Washington Post reports that just reaching the site of the alleged killings takes a 12-hour boat ride. Then there’s the problem of communicating with tribal members, who don’t speak Portuguese and are fearful of outsiders.
Carla de Lello Lorenzi of Survival International tells Wootson these types of conflicts likely happen more often than realized, but neither the miners or tribes are willing to report the incidents.
Black-and-white study print (8x10).
Black-and-white study print (11x14).
Orig. negative: 11x14, Nitrate, BW.
copy 1 negative: 8x10, Safety, BW.
copy 2 negative: 4x5, Safety, BW.
In 2017, Brazilian officials embarked on a long journey into the depths of the Amazon forest to monitor the isolated territories of the country’s indigenous tribes. Now, the team is revealing details about the expedition,including the first images of a group that has had no known contact with the outside world, reports Richard Pérez-Peña of the New York Times.
The expedition was undertaken by Brazil’s National Indian Foundation, or Funai, which works to protect the rights of indigenous groups. Among the images that the organization released is drone footage showing a clearing in the Javari Valley, a large indigenous reserve. In the clip, people can be seen walking through the clearing, including one person who seems to by carrying a pole or a spear. They do not seem to notice the drone hovering high above the trees.
Funai also released still photos of objects that were found in the area: an ax made from a stone blade, a thatched hut, canoes made from the hollowed trunks of palm trees.
Images like these can help researchers study Brazil’s uncontacted peoples. "The more we know about isolated communities' way of living, the more equipped we are to protect them," Bruno Pereira, a Funai official, tells the Associated Press.
But the organization does not try to engage with remote Amazon tribes—in fact, doing so can be dangerous. According to Survival International, there are around 100 groups living in Brazil’s rainforests that choose to remain isolated from one another and from outsiders, “almost certainly [as] a result of previous disastrous encounters and the ongoing invasion and destruction of their forest home.” A major concern is disease; uncontacted peoples are highly vulnerable to infections transmitted by outsiders, and “it is not unusual” for 50 percent of a tribe to be killed by foreign illnesses within the first year of contact, according to Survival.
Other threats come in the form of loggers, miners and farmers who are pushing into indigenous territory. Some groups have fled their land due to noise and pollution, and there have also been direct attacks on indigenous peoples. Last year, for example, ten tribespeople were reportedly killed by gold miners in the Javari Valley.
In July, Funai released a brief video clip of an uncontacted man who is has been living on his own in the jungles of Rondônia State for more than two decades. The other members of his tribe were likely killed by ranchers.
Funai’s expedition into the Javari Valley involved travelling more than 110 miles in “boats, trucks, motorcycles,” and then another 75 miles on foot, the group said in a statement. Officials were accompanied by the police. During the trek, they came across two groups of illegal hunters, as well as land and livestock owners who were encroaching onto indigenous territory.
Wallace Bastos, president of Funai, tells the AP that he hopes the newly released footage and images will help raise awareness about Brazil’s uncontacted peoples.
"These images have the power to make society and the government reflect on the importance of protecting these groups," he says.
With a name like "Treasure Island," Bolivia's Isla del Tesoro isn't what you'd expect.
First, the island isn't really an island at all, but a landlocked, forested mound about a quarter of the area of a football field that rises slightly from the tropical lowlands of the Bolivian Amazon. The place is only encircled by water when seasonal rains flood the surrounding savanna. And second, no buried gold or chests of jewels have been found there. Isla del Tesoro's treasure is much more subtle.
Archaeologists and earth scientists have been investigating Isla del Tesoro over the last decade, and they've found a 10,600-year-old garbage dump filled with layers and layers of snail shells, animal bones and charcoal from campfires which have accumulated over several millennia. Now, the researchers have more direct evidence that the forest island was created by humans: the remains of a person who was buried intentionally at the site at least 6,300 years ago.
The grave is one of five human burials that were recently uncovered in the artificial forest islands of Bolivia's Llanos de Mojos region, according to a study published today in Science Advances.La Chacra forest island in the Bolivian Llanos de Moxos, one of the sites where archaeological excavations revealed the existence of Early and Middle Holocene human occupations including burials. (José Capriles / PSU)
"As far as I am aware, these are the oldest human remains documented in southwestern Amazonia," says José Capriles, the study's lead author and an assistant professor of anthropology at Pennsylvania State University. "There are older human skeletons from neighboring regions such the karstic cave complexes of the Mina Gerais region in Brazil or the Andean highlands, but not from this region."
In the Amazon lowlands, researchers rarely find burials or any archaeological remains from the period before ceramics were developed. The acidic soil and tropical climate often prevent the preservation of human remains or artifacts, but the abundance of calcium carbonate from shells helped to preserve the newly uncovered burial sites.
The burials and refuse heaps attest that hunter-gatherers occupied this region earlier than archaeologists had expected. People on the move generally don't build landfills or bury their dead in specific places, and the archaeological evidence on the Llanos de Moxos forest islands offers new insight into the ways hunter-gatherers were able to permanently alter the landscape, creating seasonal settlements before the dawn of agriculture.
"These sites might represent some of the earliest forms of earthworks in the region," says Bronwen Whitney, a geographer from Northumbria University, who wasn't involved in the new study.Burial in La Chacra with human remains entombed in calcium carbonate. (José Capriles / PSU)
The Llanos de Moxos, a tropical savanna in northern Bolivia, attracts archaeologists because agricultural societies built an extensive network of ceremonial mounds, raised fields, roads and canals in the region beginning around 2,500 years ago. Study coauthor Umberto Lombardo, a geographer and earth scientist at the University of Bern, says he was particularly intrigued by the forest islands that stuck out of the landscape.
"When I first surveyed Isla del Tesoro in 2007, I was completely lost," Lombardo says. "I could not imagine what that was. I thought it had to be anthropogenic because I could not think of any natural process that could create such a deposit. However, it was only after the lab analyses that I started realizing that these islands not only were anthropogenic but actually far older than any other known archaeological remains in the whole region."
Lombardo, Capriles and colleagues published their initial results from Isla del Tesoro and two other forest islands in 2013 in the journal PLOS ONE. But over the course of excavations between 2012 and 2015, the researchers also found burials—one at Isla del Tesoro, three at a forest island called La Chacra and one at a forest island called San Pablo. The skeletons had been entombed in calcium carbonate from the surrounding shells, helping to preserve the remains in the hot and humid Amazon environment. Based on radiocarbon dating of nearby material, the researchers believe these burials are more than 6,000 years old.
Scientists think that during the rainy season, when the Llanos de Moxos flooded, people camped out on the forest islands collecting snails, swamp eels, catfish and other creatures from the surrounding wetlands. The forest islands were probably not intentional earthworks, but rather were created as people kept returning to the same high-ground camps over and over again between 10,600 and 4,000 years ago.
"Once they started dropping food waste and other remains in one site, they ameliorated the fertility of this site and elevated its topography over the landscape," Lombardo says. "These two processes made this site covered with forest, providing shade and construction materials. Also, it became elevated and remained above the water level during the seasonal flood. Basically, the more the site was occupied, the better it became for further occupation."Excavation team taking measurements in the Bolivian Llanos de Moxos region. (José Capriles / PSU)
Researchers now know that the invention of agriculture wasn't a single event occurring in the Middle East's Fertile Crescent and spreading to other regions. Rather, farming was independently developed in several different places around the globe. Lombardo says that, based on genetic evidence, many scholars think southwestern Amazonia was one of the earliest centers of plant domestication in South America. The region may have been a hotspot for crops like manioc, sweet potatoes, wild rice, chili peppers and peanuts.
Some of the behaviors observed on the Llanos de Moxos forest islands could have even laid the groundwork for farming, the research team says. For example, the increased consumption of low-return foods like snails suggests the foragers may have started to deplete some of their other food resources. Intentional burials could also be a sign of increased territoriality and decreased mobility, driving foragers to begin experimenting with agriculture.
Whitney says that although the study brings fresh understanding of the early foragers, our knowledge still contains gaps regarding how these populations became farmers, which the discovery of additional sites could fill. "As the authors note, there is encouraging evidence that new sites with longer sequences will soon be discovered to enable in-depth study of the emergence of agricultural societies."
John Walker, an archaeologist at the University of Central Florida who has studied the Llanos de Moxos, says the new findings are a "significant step" toward better understanding the long-term heritage of indigenous Amazonians, who have historically combined all kinds of economic strategies to sustain their lifestyle, including farming, fishing, foraging and forest management.
"There are many thousands of forest islands like these three, and they were clearly very important places to pre-Columbian communities for a very long time," Walker says. "This paper does a great service in showing how long that story is."