Tuesday, June 08, 2021

Paleontologists for the first time discover the pierced skull of a Pleistocene cave bear

Probably the find is the only evidence in the world that ancient people hunted Pleistocene small cave bears

URAL FEDERAL UNIVERSITY

IMAGE: SUCH ARROWHEAD (LEFT) WAS PROBABLY USED TO KILL THE BEAR. view more
CREDIT: URFU / ELIZAVETA VERETENNIKOVA.

Russian paleontologists discovered the skull of a Pleistocene small cave bear with artificial damage in the Imanay Cave (Bashkiria, Russia). A bear aged 9-10 years was killed with a spear during hibernation about 35 thousand years ago. If the assumptions of scientists are confirmed, the find will become the world's first direct evidence of a Paleolithic man hunting for a small cave bear. The description of the skull was published in the Vestnik Archeologii, Anthropologii I Ethnographii.

"The hole in the skull could be either natural or artificial," said senior researcher of the laboratories at the Ural Branch of the Russian Academy of Sciences and the Ural Federal University Dmitry Gimranov. "In the first case, for example, a stone could fall on the bear's head, or water dripped onto the skull during thousands of years. But this is highly unlikely. Most likely the animal was killed by ancient people."

To establish whether the bear was killed or not, scientists have to find out when the hole was made - during life or after the death of the animal. In the second case, the hole can be evidence of a ritual.

"In the Paleolithic, ritual, sacred practices were widespread," said Dmitry Gimranov. "These are handicrafts made of bones, and drawings on the walls of caves not only mammoths' and much more. Therefore, a hole in the skull could have been made after the death of the bear as a ritual practice. The facts of hunting for bears in general at that time are extremely rare. For example, in Europe, many cave bears' bones of were found. But for millions of finds, only 20-30 bones have traces of felling, which means that the meat was removed from the animal for eating. And there is only one fact of the hunt. European researchers have found a stone tip in the vertebra of a bear. There have been no such finds in Russia before. Moreover, all found with traces of human hands belong to large cave bears."

As Gimranov said, hunting for large mammals was essential for life support of ancient humans. However, hunting for small cave bears was not a specialty of the ancient hunters who left traces of their stay in the Imanay cave. At the same time, Paleo human has such strength that he could pierce the bear skull with a spear at close range with relative ease.

Note

The excavations in the Imanay cave, which is located in the Bashkiria National Park, have been carried out by researchers for three years. During this time, paleontologists have collected more than 10 thousand remains of the Late Pleistocene period. Researchers from Yekaterinburg, Moscow, Ufa take part in this study.

Cave bears inhabited the territory of northern Eurasia in the Late Pleistocene (250-10 thousand years ago). These animals were often found in the faunas of Western Europe, the Russian Caucasus, and the Urals. Finds of cave bear bones are common in caves and sometimes form huge clusters. But the caves were inhabited not only by animals but also by ancient man. Therefore, the joint finding of the bones of a cave bear and artifacts is not uncommon. However, the Pleistocene small cave bear is not a very common type of cave bear. For the first time, its remains were found in Great Britain in 1922. Later, the Russian academician Aleksey Borisyak collected and described more voluminous material in Krasnodar (Russia). He named the new species the Russian cave bear. Subsequently, it became known as the "small cave bear". Both in Russia and the West, "traces" of this species are very rare.

Really large finds are associated with excavations in the 1970s - 1980s in the Kizel Cave in the Perm Region (the finds are stored in St. Petersburg). Ural paleontologists were fortunate enough to discover the Imanay cave, where the bones of a small cave bear turned out to be several times larger than in Kizel Cave. Today, Imanay Cave is the largest deposit of the remains of a small cave bear in the world.

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Fragility fractures cost European health care systems €56.9 billion annually

New International Osteoporosis Foundation report provides unique overview of osteoporosis in Europe, revealing the enormous disease burden and an unacceptable treatment gap; 71% of women at high risk of fracture are not receiving much-needed medication

INTERNATIONAL OSTEOPOROSIS FOUNDATION

Research News

IMAGE: SCOPE 2021 SCORECARD FOR OSTEOPOROSIS IN EUROPE ILLUSTRATES THE SCORES ACROSS FOUR DOMAINS FOR 29 COUNTRIES IN EUROPE (EU27 +2). THE ELEMENTS OF EACH DOMAIN IN EACH COUNTRY WERE SCORED... view more
CREDIT: INTERNATIONAL OSTEOPOROSIS FOUNDATION

June 7, 2021 - Nyon, Switzerland -- A new report by the International Osteoporosis Foundation (IOF) draws attention to the burden of osteoporosis and the gaps and inequalities in the provision of primary and secondary prevention of fractures due to osteoporosis across Europe. 'SCOPE 2021: a new scorecard for osteoporosis in Europe' provides detailed findings for the 27 countries of the European Union as well as Switzerland and the United Kingdom (referred to as 'EU27+2'), covering key indicators for four domains: burden of disease, policy framework, service provision and service uptake.

Professor John A. Kanis, IOF Honorary President and lead author of SCOPE, stated:

"Osteoporosis is a major concern in Europe as it results in 4.3 million fragility fractures and health care costs in excess of €56 billion annually. Seeking to prioritize osteoporosis prevention in the EU27+2 countries, the SCOPE 2021 report has tracked key indicators of burden and service uptake which will help Europeans measure how well their country is able to provide quality care, including access to risk assessment and medications. It also provides a new benchmark to follow trends in osteoporosis management, and to measure future progress."

Osteoporosis is a progressive chronic disease that causes bones to become fragile and weak, leaving individuals at high risk of fragility fractures. Such fractures can have a serious impact on the sufferer, leading to pain, long-term disability and even premature death. In the EU27+2, there were estimated to be more than a quarter of a million fragility fracture-related deaths in 2019. This number is comparable to, or exceeds, other common causes of death such as lung cancer, diabetes, or chronic lower respiratory diseases.

Osteoporosis and fragility fractures place a heavy burden on Europe's population

SCOPE 2021 examined the burden of osteoporosis and fragility fractures in the EU27+2 countries, finding:

The total direct cost of fragility fractures was immense at €56.9 billion in 2019. This comprises €36.3 billion for direct costs of incident fractures, €19.0 billion for ongoing long-term disability costs (from fractures that occurred before 2019), and €1.6 billion for assessment and pharmacological treatment.
The average direct cost of osteoporotic fractures was €109.1 for each individual - in comparison, in 2010 the average for the EU27 was €85 (after adjusting for inflation).
Based on the WHO / bone mineral density criteria, there were approximately 32.0 million individuals with osteoporosis, of which 6.5 million were men and 25.5 million were women (2019).
An estimated 4.3 million new fragility fractures occurred in 2019--equivalent to 11,705 fractures/day (or 487 per hour).
Based on ten-year probability of a major fracture, 23.8 million Europeans had a probability of major fracture above the thresholds for high risk.
There was a marked difference in fracture risk among the countries. The probability of future hip fracture in men and women at the age of 50 years varied from 3.8-10.9% in men and 7.0-25.1% in women.
Given the projected increase in the aged population, the annual number of osteoporotic fractures in the EU27+2 is projected to rise by +24.8%; from 4.28 million in 2019 to 5.34 million in 2034.

Service provision lags in many countries

SCOPE 2021 also found notable inadequacies in service provision that hinder many Europeans from getting the care they need to prevent osteoporosis and fragility fractures:

In many countries there is suboptimal availability of DXA scanners, which are used to diagnose and monitor osteoporosis. Ten countries reported having less than the estimated minimum DXA units required, and only 15 of the 29 countries provide full reimbursement.
A wide variety of approved medications is available for the management of osteoporosis. Less than half of the countries offered full reimbursement for these medications.
Post-Fracture Care Coordination Programs (or Fracture Liaison Services) in hospitals were lacking in eight countries. Based on expert opinion, approximately half of the remaining countries reported that less than 10% of hospitals had such vital programs in place.

Large treatment gap indicates need for strategies to improve service uptake

Among the most startling findings of SCOPE 2021 is the enormous 'treatment gap' which is leaving the most high risk individuals unprotected against fragility fractures. Other measures of service uptake were also found to be suboptimal:

In 2019 an average of 71% of women at high fracture risk did not receive therapy for osteoporosis, ranging from 32% (Ireland) to 87% (Bulgaria).
In 2010 the gap was estimated at 55% (or 10.6 million women) who were eligible for treatment but were untreated - this number has risen to 14.8 million in 2019.
FRAX, the most commonly used risk assessment tool, is available for 24 of the 29 countries. However, its web-based usage varied widely from 49 to 41,874 sessions per million population. This indicates that the tool is underutilized in most countries.
Waiting times between admission to hospital and surgical intervention were on average greater than 48 hours in five of the 29 countries. Early surgery within 48 hours of a hip fracture has been shown to significantly reduce mortality and increase the proportion of patients returning to their original residence.

Professor Cyrus Cooper, President of IOF, welcomed the publication of SCOPE 2021 and urged European health authorities to prioritize osteoporosis and fracture prevention:

"This important publication clearly shows that osteoporosis is a major health care burden in Europe, resulting in enormous, and growing, costs to national health care systems. As well as revealing wide discrepancies in service provision and uptake within the EU, SCOPE has exposed an unacceptable treatment gap and poor provision of post-fracture care programs to prevent secondary fractures. Despite the wide availability of treatments to prevent fractures, only a minority of patients at high risk receive treatment even after their first fracture."

"IOF joins national osteoporosis societies in Europe in calling for a Europe-wide strategy and parallel national strategies to provide coordinated osteoporosis care and to reduce debilitating fractures and their impact on individual lives and health care systems. Given the projected increase in fracture burden, urgent action must be taken."

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Antarctica: How have temperatures varied since the last glacial period?

CNRS

Research News

Scientists have established the most reliable estimates to date of past temperature variations in Antarctica.
They highlight significant differences in behaviour between West and East Antarctica.
This study makes it possible to test and consolidate future climate projections.

Antarctica has experienced significant temperature changes, especially since the last glacial period. An international collaboration including scientists from the CNRS1 has now challenged previously accepted estimates of these variations, using new measurements published on June 4, 2021 in Science. Their study highlights differences in behaviour between East and West Antarctica, connected in particular to differing variations in their altitude.

Surface temperatures in Antarctica have risen sharply since the last glacial period. Understanding this increase is key to understanding changes in climate at any given time and to testing our ability to model them. A study involving French scientists now provides the most reliable estimates to date of past temperature variations in Antarctica. Whereas warming since the last glacial period was until now estimated at +9 °C across the entire continent, the new measurements reveal a variation of +10 °C in West Antarctica and between +4 and +7 °C in East Antarctica.

Scientists previously estimated past temperatures using an isotopic thermometer, in other words, by analysing the ratio of different isotopic forms of water. However, the accuracy of this method relies on a calibration that is hard to implement in Antarctica. Now, two new independent methods have been developed in order to overcome this problem. The first consists in measuring the temperature in the boreholes resulting from coring2. The tremendous thickness of the Antarctic ice sheet means that records are well-preserved and can be used to reconstruct past temperatures. The second method is based on the process of snow densification, which is temperature-sensitive and can be measured by analysing the air trapped in ice cores. The two measurements gave similar results, confirming their reliability.

This work highlights the impact on temperature changes in Antarctica caused by variations in the altitude of the ice. It demonstrates the significant differences between East Antarctica, whose elevation has increased slightly since the last glacial period, and West Antarctica, where it has decreased considerably. The data was compared with climate models3 in order to better understand past temperature changes and improve confidence in future projections.

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CAPTION

Temperature probe developed at the Institute of Environmental Geosciences (OSUG, CNRS / IRD / UGA / Grenoble INP) to collect data from the EPICA borehole at Concordia.

CREDIT

Study sheds light on pre-Columbian life in understudied area of SW Amazon

Evidence showing intensive land use for farming and fishing more than 3,500 years ago helps researchers better understand the history of a culturally significant area and is counter to the often-held notion of a pristine Amazon before Europeans arrived

UNIVERSITY OF CENTRAL FLORIDA

Research News

IMAGE: AS PART OF THIS STUDY, THE RESEARCHERS COMMISSIONED AN ILLUSTRATION BY ARTIST KATHRYN KILLACKEY. THE ILLUSTRATION IS A REPRESENTATION OF THE PRE-COLUMBIAN LANDSCAPE AROUND 3,500 YEARS AGO, BASED ON THEIR... view more
CREDIT: KATHRYN KILLACKEY

ORLANDO, June 2021 - A new study co-authored by University of Central Florida researchers shows that pre-Columbian people of a culturally diverse but not well-documented area of the Amazon in South America significantly altered their landscape thousands of years earlier than previously thought.

The findings, published in the journal Proceedings of the National Academy of Sciences, show evidence of people using fire and improving their landscape for farming and fishing more than 3,500 years ago. This counters the often-held notion of a pristine Amazon during pre-Columbian times before the arrival of Europeans in the late 1400s.

The study, which was conducted with experts from the UK's Northumbria University, also provides mores clues to the past of the diverse, but not well-documented, cultures that live in the area known as the Llanos de Mojos in northeastern Bolivia.

"This region has one the highest diversity of languages in the world, which reflects distinct ways of life and cultural heritage," says study co-author John Walker, an associate professor in UCF's Department of Anthropology. "We know something about the last 3,000 to 4,000 years of, say Europe or the Mediterranean, but we don't have some of that same information for the people here. That makes this an incredible story waiting to be written."

Part of the way researchers hope to write these stories is to uncover the economic practices of the distant past.

The flat, wetland landscape of the Llanos de Mojos is used for cattle ranching today, but archaeologists have noted for years the evidence from remnants of pre-Columbian raised fields and fish weirs for aquaculture. These remnants indicated the land was once used instead for farming and fishing. The archaeologists just didn't know when or how far back in time these activities started -- until now.

Previous research pointed to a date of about 300 C.E., or about 1,700 years ago. However, the new study combined expertise from multiple disciplines, such as anthropology, paleoethnobotany and paleoecology, to indicate that intensive land management started much earlier, at about 1,500 B.C.E, or about 3,500 years ago.

"This finding is important because it provides evidence that the Amazon is not a pristine wilderness but has been shaped and designed by indigenous people thousands of years before the Spanish arrived," Walker says.

This is new information for both the history of the cultures of the Amazon, which have not been studied as much as other cases, like the Mayas or Incas, and for the area, which is often thought of as an untouched world before the arrival of the Spanish.

Neil Duncan, the study's lead author and a paleoethnobotanist in UCF's Department of Anthropology, specializes in studying archaeological and paleoenvironmental plant remains to learn how humans and plants interacted in the past.

With help from the research team, Duncan extracted two, five-foot long cores of earth from two locations about 13 miles apart in the Llanos de Mojos.

By examining these cores, Duncan found corn and squash phytoliths dating as early as 1380 B.C.E and 650 B.C.E, or about 3,000 years ago. Phytoliths are microscopic silica particles from plant tissue, and the findings suggest these were crops grown in the numerous raised fields that dot the area.

Colleagues from Northumbria University in the United Kingdom examined the cores for charcoal, pollen and diatoms, which are single-celled alga indicative of aquatic environments.

Both cores showed similar trends of initial dry conditions in the oldest layers of earth, followed by increased wet conditions and increased use of wood burning, as evidenced by the presence of high diatom concentrations and charcoal concentrations, respectively. The researchers say wood burning could be for cooking, pottery, warmth and more.

"This is the first time that we've been able to show in the past how people managed their land and water resources in a coupled system," says Bronwen Whitney, an associate professor of geography and environmental sciences who led the research by the Northumbria University team. Whitney is an expert in historic environmental changes, particularly in South and Central America.

"The intensification of plant, fire and water management occurred at the same time, which emphasizes how farming or fishing were equally important to the people of the region," Whitney says.

Also of note is that the shifts in the two cores to more intensive land management happened at different periods, the researchers say.

One core, known as the Mercedes core, showed the shift to wetter conditions and increased fire use starting at 1,500 B.C.E, or about 3,500 years ago. The other, extracted from a location about 13 miles farther south and known as the Quinato-Miraflores core, showed the shift occurring at about 70 B.C.E., or about 2,100 years ago.

Since broadscale climate changes would have affected both areas at the same time, the time difference between the two cores suggests humans were purposefully engineering the land, including draining water in some areas, retaining it in others, and using trees for fuel.

"So, what's happening in the landscape is that that it's becoming wetter, and we think that some of those trees are being flooded out and so they're not as well represented," Duncan says. "And if things are getting wetter then we shouldn't see more charcoal. So, the interpretation is that we would only see these high amounts of charcoal if it's humans doing some very intentional and intensive burning."

The researchers say the next steps are to investigate the function, history, and role of the area's fish weirs and to apply new techniques to date earthworks directly and reconstruct a more detailed agricultural history for the region.

As part of this study, the researchers commissioned an illustration by artist Kathryn Killackey. The illustration is a representation of the pre-Columbian landscape around 3,500 years ago, based on their reconstruction, and details what they believe the region would have looked like at the time.

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The research was funded by a U.S.-U.K. collaborative funding partnership with the National Science Foundation (1758273) and the Arts and Humanities Research Council (AH/S00128X/1).

Study co-authors were Nicholas J.D. Loughlin and Emma P. Hocking with the Department of Geography and Environmental Sciences at Northumbria University, Newcastle upon Tyne, England.

The researchers also worked closely with the Bolivia Ministry of Cultures, Unidad Nacional de Arqueologia y Museos, Museo Regional Arqueologico "Yacuma," and researchers and students from the Universidad Mayor de San Andres in La Paz.

Duncan received his doctorate in anthropology from the University of Missouri and joined UCF's Department of Anthropology, part of UCF's College of Sciences, in 2015. Walker received his doctorate in anthropology from the University of Pennsylvania and joined UCF's Department of Anthropology in 2006.

CONTACT: Robert H. Wells, Office of Research, robert.wells@ucf.edu

Indigenous peoples were stewards of the Western Amazon

Study points to a history of indigenous sustainable use of the Western Amazon stretching back 5,000 years

SMITHSONIAN

Research News

IMAGE: AN AERIAL PHOTO OF THE ALGODÓN RIVER FLOWING THROUGH A FOREST OF THE AMAZON BASIN IN THE REMOTE NORTHEASTERN CORNER OF PERU. TO EXPLORE THE EXTENT AND SCALE OF INDIGENOUS... view more
CREDIT: ÁLVARO DEL CAMPO

Smithsonian scientists and their collaborators have found new evidence that prehistoric Indigenous peoples did not significantly alter large swaths of forest ecosystems in the western Amazon, effectively preserving large areas of rainforests to be unmodified or used in sustainable ways that did not reshape their composition. The new findings are the latest in a long scientific debate about how people in the Amazon have historically shaped the rich biodiversity of the region and global climate systems, presenting new implications for how the Amazon's biodiversity and ecosystems can be best conserved and preserved today.

In recent years, scientists' understanding of the Amazon rainforest has been increasingly informed by a body of research that suggests the landscape was actively, intensively shaped by Indigenous peoples before the arrival of Europeans. Some studies ascribe the tree species that now dominate the forest to prehistoric human management and landscape engineering. Other work posits that when colonizers from Europe caused massive losses to Indigenous Amazonians with disease, slavery and warfare, the sudden interruption in landscape-scale manipulation resulted in so much forest regrowth that it caused a global drop in atmospheric carbon dioxide that brought about a climactic shift that is known as the "Little Ice Age."

Now a new study led by Smithsonian researchers, published June 7 in the journal Proceedings of the National Academy of Sciences, suggests that for at least the past 5,000 years, large areas of the rainforest in western Amazonia located away from the fertile soils near rivers were not periodically cleared with fire or subject to intensive land use by the Indigenous population before the arrival of Europeans.

The study, led by Smithsonian senior scientist emerita Dolores Piperno of the National Museum of Natural History and the Smithsonian Tropical Research Institute in Panama, is the latest entry in a nearly decade-long scientific debate over prehistoric human influence in the world's largest rainforest.

"Far from implying that complex, permanent human settlements in Amazonia had no influence over the landscape in some regions, our study adds substantially more evidence indicating the bulk of the Indigenous population's serious impact on the forested environment was concentrated in the nutrient-rich soils near rivers, and that their use of the surrounding rainforest was sustainable, causing no detectable species losses or disturbances, over millennia," Piperno said.

To explore the extent and scale of Indigenous modification of the Amazon, Piperno and her co-authors collected and analyzed a series of 10 roughly 3-foot-long soil cores from three sites in the remote northeastern corner of Peru.

The three sites were located at least a half-mile (about 1 kilometer) away from river courses and floodplains, known to researchers as interfluvial zones. Interfluvial forest comprises more than 90% of the Amazon's land area and is therefore crucial to determining the extent of Indigenous influence on the landscape, precisely because most major settlements identified by archaeologists thus far are near rivers.

Piperno and her co-authors used the soil cores to create timelines of plant life and fire history at each location going back some 5,000 years. To do this, the team extracted long-lasting microfossil particles of dead plants called phytoliths and looked for traces of fire such as charcoal or soot. Fire, in a landscape that receives nearly 10 feet of rain annually, is nearly always human in origin and would have been instrumental in clearing large areas of land for human uses, such as agriculture and settlement.

The team identified which plant type each phytolith belonged to by comparing them with a comparative reference library of modern plants and used radiocarbon dating to reveal how long ago the plants lived. The dating of both phytoliths and charcoal determined the age of the plant fossils and any remnants of fire found in a core.

Finally, the researchers also conducted surveys of the modern forests found around each core. These forest inventories evinced the dizzying diversity of the region, yielding 550 tree species and 1,300 other species of plants.

Piperno said all the analyses pointed in the same direction: "We found no evidence for crop plants or slash and burn agriculture; no evidence for forest clearing; no evidence for the establishment of forest gardens. These are very similar to results from other regions of Amazonia. We now have a substantial amount of evidence that extensive, wholesale alterations of forest across the interfluvial areas of Amazonia did not occur in prehistory."

Instead, the researchers saw a rainforest ecosystem that remained relatively stable for thousands of years and is much like the ones still standing in similarly undisturbed regions today.

"This means that ecologists, soil scientists and climatologists looking to understand this region's ecological dynamics and capacity for storing carbon can be confident that they're studying forests that haven't been heavily modified by people," Piperno said.

But she says it also means we "should not assume the forests were once resilient in the face of significant past disturbance," and added that this has important implications for "good sustainable land use and conservation policies" because such policies "require adequate knowledge of past anthropogenic and natural impacts on the Amazonian ecosystem together with its responses."

In light of these results, Piperno and the research team also find the idea that reforestation following the arrival of Europeans triggered the Little Ice Age implausible.

"Without significant forest clearing in these and other regions studied by our team and others it appears unlikely that there was sufficient forest regeneration to have affected global carbon dioxide after European contact," Piperno said.

As for why there does not appear to have been any large-scale modification of the interfluvial Amazon, the simplest explanation for the pattern may be in the soil, which has so few nutrients that it would not have been desirable for crops and other plant manipulations compared to areas on riverbanks and floodplains.

Piperno said that more work still needs to be done in other yet unstudied regions away from riverbanks and floodplains to obtain a wider view of the vast Amazon and that the team's results do not imply that no form of Indigenous forest management occurred in the region, just that it was not intensive enough to show up in the soil cores.

"To me, these findings don't say that the Indigenous population wasn't using the forest, just that they used it sustainably and didn't modify its species composition very much," Piperno said. "We saw no decreases in plant diversity over the time period we studied. This is a place where humans appear to have been a positive force on this landscape and its biodiversity over thousands of years."

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Funding and support for this research were provided by the Smithsonian, the National Science Foundation, the Wenner-Gren Foundation for Anthropological Research, the European Research Council and the Gordon and Betty Moore Foundation.

CAPTION

An interior view of the Amazon Basin forests where scientists sampled soil cores for their study, with each site located at least a half-mile (about 1 kilometer) away from river courses and floodplains--regions known to scientists as interfluvial forests. The researchers also conducted surveys of the modern forests found around each core. These forest inventories evinced the dizzying diversity of the region, yielding 550 tree species and 1,300 other species of plants. Interfluvial forest comprises more than 90% of the Amazon's land area and is therefore crucial to determining the extent of Indigenous influence on the landscape. Smithsonian scientists and their collaborators have found new evidence that prehistoric Indigenous peoples did not significantly alter large swaths of forest ecosystems in the western Amazon, effectively preserving large areas of rainforests to be unmodified or used in sustainable ways that did not reshape their composition. The new findings are the latest in a long scientific debate about how people in the Amazon have historically shaped the rich biodiversity of the region and global climate systems, presenting new implications for how the Amazon's biodiversity and ecosystems can be best conserved and preserved today. The new study led by Smithsonian researchers, published June 7 in the journal Proceedings of the National Academy of Sciences, suggests that for at least the past 5,000 years, large areas of the rainforest in western Amazonia located away from the fertile soils near rivers were not periodically cleared with fire or subject to intensive land use by the Indigenous population before the arrival of Europeans.

CREDIT

Corine Vriesendorp

CAPTION

Long-lasting microfossil particles of dead plants called phytoliths seen under a microscope, sampled from soil cores taken by scientists from the Amazon Basin. Most phytoliths studied by the team were smaller than the width of a human hair. Scientists used the soil cores to create timelines of plant life and fire history at each location going back some 5,000 years. To do this, the team extracted phytoliths and looked for traces of fire such as charcoal or soot. Fire, in a landscape that receives nearly 10 feet of rain annually, is nearly always human in origin and would have been instrumental in clearing large areas of land for human uses, such as agriculture and settlement. Smithsonian scientists and their collaborators have found new evidence that prehistoric Indigenous peoples did not significantly alter large swaths of forest ecosystems in the western Amazon, effectively preserving large areas of rainforests to be unmodified or used in sustainable ways that did not reshape their composition. The new findings are the latest in a long scientific debate about how people in the Amazon have historically shaped the rich biodiversity of the region and global climate systems, presenting new implications for how the Amazon's biodiversity and ecosystems can be best conserved and preserved today. The new study led by Smithsonian researchers, published June 7 in the journal Proceedings of the National Academy of Sciences, suggests that for at least the past 5,000 years, large areas of the rainforest in western Amazonia located away from the fertile soils near rivers were not periodically cleared with fire or subject to intensive land use by the Indigenous population before the arrival of Europeans.?

CREDIT

Dolores Piperno, Smithsonian.

This forest has stayed wild for 5,000 years -- we can tell because of the soil

FIELD MUSEUM

Research News

We sometimes think of the Amazon rainforest as unaltered by humans, a peek into the planet's past. In recent years, scientists have learned that many parts of the Amazon aren't untouched at all--they've been cultivated by Indigenous peoples for thousands of years, and mere centuries ago were the sites of cities and farmland. But that's not the case everywhere. In a new study in PNAS, researchers determined that a rainforest in the Putumayo region of Peru has been home to relatively unaltered forest for 5,000 years, meaning that the people who have lived there found a long-term way to coexist with nature--and the evidence is in microscopic bits of silica and charcoal in the soil.

"It's very hard even for experienced ecologists to tell the difference between a 2,000-year-old forest and a 200-year-old forest," says Nigel Pitman, an ecologist at Chicago's Field Museum and a co-author of the PNAS paper. "There's more and more research showing that many Amazonian forests we think of as wilderness are actually only 500 years old, because that's when the people who were living there died from the pandemics brought by Europeans, and the forest has regrown."

Many plants take up silica from the soil and use it to produce microscopic mineral particles called phytoliths that provide structural support. After a plant dies, these phytoliths linger in the soil for thousands of years. Different kinds of plants produce differently-shaped phytoliths, meaning that phytoliths in the soil can be used to determine what kinds of plants lived there in the past.

For this study, Piperno and her colleague Crystal McMichael at the University of Amsterdam needed soil samples from the Putumayo region of the Amazon rainforest in northeastern Peru. That's where Pitman came in. In his work with the Field's Keller Science Action Center, Pitman takes part in "rapid inventories" of the Amazon, intensive information-gathering trips to document the plants and animals of a region and build relationships with the people who live there, in order to help build a case for protecting the area. Piperno and McMichael reached out to Pitman, a botanist, and asked if he'd be able to collect soil samples as he inventoried the Putumayo region's trees.

"The three or four days that we're at one of these sites feel like running a marathon. We have to get a lot done in a really short amount of time, and so we're up really early, we stay up really late, and somehow these soil cores had to be taken at the same time," says Pitman. "Sometimes we collected the soil at midnight, or during rainstorms, when we couldn't survey trees."

To collect the soil, Pitman and his colleagues, including Field Museum associates Juan Ernesto Guevara Andino, Marcos Ríos Paredes, and Luis A. Torres Montenegro, used a tool called an auger. "It's a long metal pole with blades at the bottom, and when you stick it in the ground and rotate it, it carves out a column of soil about 2 to 3 feet long." The team took samples of the soil at different heights on the column, placed them in plastic bags, and transported them back to the US for analysis.

The soil's age roughly correlates to its depth, with newer soil at the top and older soil deeper within the earth. Back in the lab, the researchers used carbon dating to determine the soil's age and then painstakingly sorted through samples under a microscope, searching for phytoliths that would tell them what kinds of plants were living in the area at a given time.

They found that the types of trees growing in the region today have been growing there over the past 5,000 years--an indicator that unlike in other parts of the Amazon, the Putumayo wasn't home to cities and farmland prior to European colonization.

In addition to phytoliths, the researchers also looked for microscopic bits of charcoal. "In the western Amazon where it's wet year-round, finding charcoal tells you that people were there," says Pitman. "There aren't natural forest fires from lightning strikes, so if something burns, it's because a person set it on fire."

The low levels of charcoal in the soil show that while the forest remained unaltered by humans for 5,000 years, people did live in the area--they just coexisted with the forest in a way that didn't change it.

"One of the scary things for conservationists about research showing that so much of the Amazon used to be towns and cropland, is that it's allowed people who aren't conservationists to say, 'If that was the case, then you conservationists are getting upset for no reason--500 years ago, half the Amazon was cut down and all grew back, it's no big deal. We don't have to worry so much about cutting down the Amazon, we've already done it and it turned out fine,'" says Pitman. This study suggests that while people are able to coexist with wilderness without altering it, the Amazon isn't simply a resource that can be destroyed and regrown from scratch in a matter of centuries.

"To me, these findings don't say that the Indigenous population wasn't using the forest, just that they used it sustainably and didn't modify its species composition very much," says Piperno. "We saw no decreases in plant diversity over the time period we studied. This is a place where humans appear to have been a positive force on this landscape and its biodiversity over thousands of years."

"It's an important finding, and a hopeful one, because it shows that people have been living in the Amazon for thousands of years, in a way that allows them to thrive and the forest to to thrive," says Pitman. "And since this particular forest is still being protected by Indigenous peoples, I hope this study reminds us all how important it is to support their work."

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Soil samples collected in the rainforest.

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Nigel Pitman, Field Museum

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Tuesday, June 08, 2021

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Study sheds light on pre-Columbian life in understudied area of SW Amazon

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This forest has stayed wild for 5,000 years -- we can tell because of the soil

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