Agricultural diffusion, population movement, and funeral practices in ancient Gansu

 

A multidisciplinary study has answered key questions about how agricultural practices diffused into ancient Gansu from Eurasia, as well as described population movements and funeral practices in the Gansu region thousands of years ago.

Gansu, now a province in northwestern China, has long been a key crossroads for transcontinental exchanges of domesticated crops and livestock. Yet it has not been clear whether such exchanges were driven by human migration—a process known as demic diffusion—or by the introduction of crops and livestock to existing populations—a process known as cultural diffusion.

Now, researchers using genomic data from 149 ancient human individuals in Gansu, have shown that the introduction of western-derived agriculture amid waves of trans-Eurasian exchange was not accompanied by direct demic diffusion.

The study, which was published in Cell on September 3, was conducted by a research team led by Professor FU Qiaomei from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences (CAS), working in collaboration with multiple institutions.

The genomic data used in the study date to around 4,700–3,000 years ago—a critical period when cereals and livestock first domesticated in western Eurasia were being introduced to the region.

According to the researchers, the results did not detect any traces of genetic influence from western Eurasia or Central Asia among the ancient individuals, despite the adoption of western-derived crops or livestock at nine of the 11 Gansu sites.

Instead, the dominant genetic ancestries detected in Gansu were linked to populations that once inhabited the Yellow River basin, the southeastern Mongolian Plateau, and the Tibetan Plateau. A few genetic outliers also pointed to interactions between Gansu and regions both nearby and farther north, including the cis-Baikal area.

These results suggest that the introduction of western-derived domesticates did not involve a direct large-scale western population influx—unlike patterns of agricultural expansion found in Europe and Central Asia. Possible explanations for this phenomenon chiefly include cultural diffusion through the Inner Asian Mountain Corridor, or transmission via exchange networks or intermediary populations across the Mongolian Steppe.

Unveiling Social Practices in Ancient East Asia

In addition to the genetic focus, the study also included information on Late Neolithic and Bronze Age social and burial practices, based on investigation of the large cemetery at Mogou (3,600–3,200 years before the present)—one of the largest excavated cemeteries in China.

The researchers noted that genetic similarities among the Gansu sites revealed a broad correlation—though not a strict alignment—between genetic ancestry and archaeologically defined cultural groups.

Through kinship and identity-by-descent (IBD) analyses, most Mogou individuals were found to form a broadly linked network based on biological relatedness that persisted through the transition from the Qijia to the Siwa archaeological cultures, pointing to a continuous and connected society.

The researchers also found evidence of endogamy at Mogou, as two individuals showed signs of parental consanguineous mating, while runs of homozygosity segments hinted that Mogou may also have practiced some level of exogamy, finding some mates from outside communities. Furthermore, female and male individuals at Mogou did not exhibit significant differences in relatedness, suggesting that the Mogou community did not strictly maintain either patrilocal or matrilocal residence patterns.

By integrating burial practices and genetic patterns, the results showed that genetic outliers—individuals who were not close biological relatives of core community members—were more likely to be buried in settings archaeologically interpreted as lower-status. As for biological sex, while males were predominantly buried with food production tools and females with spinning wheels, no significant differences were found in other burial practices analyzed, such as burial location or the number of funerary objects.

Surprisingly, no strong correlation emerged between genetic relatedness and burial distance among the sampled burials in the cemetery. Within tombs containing multiple burials, no first- or second-degree relatives were found buried together, and some co-buried individuals may have had mixed social status or have been interred at different times.

These results imply that burial customs at Mogou were not strictly centered on biological relatedness, and that other interpersonal relationships, along with the repeated use of tombs over different time periods, likely also played a role in determining who shared a tomb.

According to the researchers, this multidisciplinary study provides important insights into population movements amid waves of trans-Eurasian exchange—demonstrating that the introduction of western-derived agriculture was not accompanied by direct demic diffusion—while also shedding light on the extensive kinship networks and complex burial customs of the local community at Mogou.

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Journal

Cell

DOI

10.1016/j.cell.2026.07.050 

Article Title

Traces of nearly four million coins reveal how Rome achieved economic integration

 

For centuries, the study of ancient history relied primarily on interpreting classical texts and examining inscriptions and archaeological remains at their sites of origin or in museums. In recent years, however, a little-known transformation has profoundly changed this landscape. The digitization of extensive archaeological collections, coupled with the development of quantitative methods that can integrate millions of scattered records, is ushering in a new era of historical research. Like other scientific disciplines that have benefited from processing colossal amounts of information, archaeology and history have entered the era of data science.

Two researchers from the Regional and Urban Economics Lab at the University of São Paulo (NEREUS-USP) in Brazil have just presented an example of this approach. Using techniques from regional economics, spatial analysis, geographic information systems, and large international archaeological databases, they reconstructed the monetary circulation of the Roman Republic, focusing on the period from 155 BCE to 2 CE, based on the remains of approximately four million coins found in excavations conducted over two centuries. Their study shows that the consolidation of Roman rule depended less on military conquest and more on the economic integration of the territories they conquered.

The research was conducted by Eduardo Amaral Haddad, a professor at the School of Economics, Business, and Accounting (FEA-USP), and Inácio Fernandes Araújo, currently a professor at the Luiz de Queiroz College of Agriculture (ESALQ-USP). The two authors published an article in the journal Humanities and Social Sciences Communications, which is part of the Nature group.

The research seeks to understand how coins reflect the functioning of a growing economy, going beyond simply tracking their movement. “Each coin preserved by archaeology provides three key pieces of information: where it was minted, when it was produced, and where it was found some 2,000 years later. Taken in isolation, that information reveals little. However, when millions of records are analyzed together, they can reveal the paths taken by money, the intensity of economic exchanges, the integration between different regions, and even the institutional evolution of one of the largest economies of antiquity,” says Haddad.

The research was supported by FAPESP through two projects (14/25030-2 and 19/00057-9).

A study that began as a hobby

The project originated in 2014 when Haddad, already a professor at FEA-USP, took a sabbatical at Princeton University in the United States. Although he was conducting research in economics, he began attending a weekly seminar organized by the Department of Classical Studies out of personal interest.

“At one of those meetings, I attended a presentation of a study that used shipwreck remains and pottery shards to reconstruct trade networks in the ancient Mediterranean. That idea stuck with me. Shortly thereafter, while exploring the university library, I found a catalog of Roman coins that contained the information I needed: the date of minting, the location where each coin was produced, and the site where it was found during archaeological excavations. I photocopied the catalog, thinking it would be possible to analyze those networks using tools from regional and urban economics,” he recalls.

That initial interest eventually turned into a long-term project. To deepen his knowledge of the classical world, Haddad enrolled in a distance-learning graduate program on the ancient Mediterranean offered by the University of Leicester in the United Kingdom. One of the papers he wrote during the program became the basis for a published article.

Computational archaeology

For a long time, information on Roman coins was scattered among museums, libraries, private collections, and researchers’ archives. This fragmentation hindered attempts to reconstruct large-scale circulation patterns. However, the situation began to change when institutions such as the American Numismatic Society started coordinating international projects to digitize and standardize these collections. These projects established common protocols for recording archaeological information. Today, large public databases bring together millions of records from excavations conducted in different countries.

“The main source for our study was Coin Hoards of the Roman Republic Online [CHRR], a database dedicated to coin hoards from the Roman Republic. The study also drew on various digital archaeology platforms. Among them was ORBIS, developed by Stanford University [United States], which simulates travel along the network of roads, rivers, and sea routes of the Roman world and estimates the time and cost of journeys between hundreds of locations. The study also included the Pleiades gazetteer and the Roman Road Network databases, which provided georeferenced information on cities, roads, and ports in the ancient Mediterranean,” Haddad explains.

These databases were integrated into a single spatial analysis system. After a careful curation process, the researchers began working with a set of approximately four million coins organized into 24,646 hoards corresponding to 5,167 pairs of minting and discovery sites. Rather than analyzing the coins individually, the researchers chose to use these archaeological records, thereby reducing distortions caused by differences in their preservation, loss, or reuse over the centuries.

However, the goal went far beyond simply creating maps. “We needed to consider that circulation from the perspective of human interaction in space according to an economic logic,” Haddad explains. It was at that moment that his expertise in regional economics found an unexpected application. The same mathematical tools developed to study contemporary flows of people, goods, and income were used to investigate monetary movements that occurred more than 2,000 years ago. Instead of analyzing modern cities, the focus shifted to the Roman Mediterranean. Instead of tracking contemporary supply chains, the researchers sought to reconstruct the economic networks that sustained Rome’s expansion during the last two centuries of the Republic.

Follow the money

The Roman Republic is conventionally dated from 509 BCE to 27 CE, when Octavian Augustus established the Principate. The last two centuries of the Republic therefore correspond to the period between 200 and 27 CE, which encompasses the consolidation of Roman hegemony following the Second Punic War (218–201 CE), the conquest of the Hellenistic Mediterranean, and the expansion into Hispania, Gaul, the Balkans, and the East. This period also includes the civil wars that led to the end of the Republic.

The researchers’ first question was simple yet decisive: Was the spatial distribution of the coins random, or did it follow a pattern? To answer this question, the team employed spatial analysis techniques widely used in regional economics and economic geography. The tests showed that the findings were far from random. On the contrary, the coins formed statistically significant clusters concentrated along the main trade routes of the Roman world.

Once this initial result was identified, an even more ambitious question arose: Would it be possible to reconstruct the paths taken by the money? “After verifying a correlation between the location and concentration of the coins, we began to cross-reference that information with Roman roads. And we found something very interesting: a clear spread of coins originating from Rome,” says Haddad.

The maps produced by the study show that monetary circulation closely followed the infrastructure built by the Roman Republic. Roads, ports, and major urban centers were not just thoroughfares; they were the channels through which the economic relations that sustained territorial expansion spread.

However, tracing the path of the coins was only the first step. The next question was why some regions had intense monetary circulation while others remained relatively peripheral.

“Answering that question required more than maps. It was necessary to reconstruct – albeit approximately – the functioning of the Roman economy itself. To do so, we organized information from historical and archaeological literature into a model inspired by so-called social accounting matrices, a tool used to analyze contemporary economies. The model describes the relationships among the main economic actors of the time: the government, households, landowners, merchants, slaves, and the army. It seeks to represent the flows of goods and payments that linked those institutions. It also distinguishes between different types of production and consumption, ranging from food and raw materials to manufactured goods and luxury items, the trade in which could extend over much greater distances,” Haddad reports.

Another aspect incorporated into the model was the gradual monetization of the Roman economy. During part of the Republic, many transactions continued to be conducted in kind. Over time, however, payments related to supplying the army, maintaining slaves, and various public activities progressively began to be made in coin. This transformation left its mark on the archaeological collections themselves. Based on this economic model, coin hoards found in excavations ceased to be mere collections of ancient coins. Instead, they are treated as material evidence of the economic relationships that structured the Roman Republic.

First the army, then the economy

At this point, one of the most interesting conclusions of the study emerged. A widely held interpretation attributes the Roman army the predominant role in disseminating currency throughout the conquered territories. This assertion seems intuitive. As the legions advanced, they brought with them soldiers who received wages and suppliers who traded goods, generating intense monetary circulation. However, the results only partially confirm this hypothesis.

According to Haddad, military structures played a decisive role in the initial phase of expansion. However, their influence waned as the new territories were permanently incorporated into the Roman world. “What we realized was that military expansion introduced monetary circulation, but it only became established once those territories were effectively integrated, creating economic, religious, administrative, and civic structures capable of generating a permanent demand for currency,” he points out. In other words, the army served as a catalyst for opening up these regions. It was the economy that ensured the permanence of the currency.

This finding helps explain why historical interpretations focused exclusively on military action fail to capture a fundamental aspect of Roman expansion. Conquering a territory was only the beginning. For it to be effectively integrated into the Republic, markets, cities, administrative institutions, religious centers, and permanent networks of exchange had to be built. The maps of currency circulation are beginning to reveal this process of integration.

Another important conclusion concerns the evolution of Roman economic geography itself. “In the early periods analyzed, coins remained relatively close to the places where they had been minted. However, as the Republic expanded its borders, they began to be found at increasingly greater distances. In statistical models, this appears as a progressive reduction in the effect of distance on coin circulation. In other words, regions previously separated by geographical barriers became progressively integrated through a common network of transportation, markets, and institutions,” Haddad explains.

According to the researcher, this is perhaps one of the most significant findings of the study. “As territorial expansion occurs, we begin to find coins at increasingly greater distances. The role of distance gradually diminishes, suggesting a growing integration of the territory,” he summarizes. This conclusion goes far beyond numismatics [the discipline dedicated to the study of coins as historical documents]. It suggests that the circulation of coins can serve as an indirect indicator of the degree of economic integration among the empire’s different regions.

Diversified markets

Spatial analysis revealed the intensity of monetary circulation and different functional regions within the Roman Republic.

“At the center of the system was the city of Rome itself, where expenditures related to public administration predominated. Surrounding it was a highly integrated economic core corresponding to the Italian Peninsula, where monetary circulation primarily reflected market activities. Further out lay an intermediate belt, a sort of buffer zone between the consolidated core and the recently incorporated regions. Within it, administrative, economic, and military expenditures coexisted. In the areas of most recent expansion, however, expenditures related to conquest and territorial occupation predominated. As those regions were pacified and permanently incorporated into the Roman world, the share of military expenditures decreased, giving way to the growth of civil, administrative, and commercial activities,” Haddad explains.

Major trends in cattle and sheep husbandry drove the economy of Medieval England

Major dataset adjusts the timeline of shifting animal production practices

Peer-Reviewed Publication

PLOS

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A pile of animal bones.

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Credit: Matilda Holmes, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

As populations expanded in Medieval England, key changes occurred in the uses of cattle and sheep to produce food and materials, according to a study published September 2, 2026 in the open access journal PLOS One by Matilda Holmes of the University of Leicester, UK, David Orton of the University of York, UK, and colleagues.

Medieval England experienced major changes in population sizes and trade networks, requiring changes in the ways that animals were used for meat, milk and arable production. Historically, the timing of these changes has been poorly understood. In this study, Holmes and colleagues investigate the changing animal economy using a large dataset provided by the Feeding Anglo-Saxon England project, including information from 460 sites across England from CE 400-1400.

Early on during this time range, cattle were far more abundant than sheep, but sheep began to increase during the 7th Century, originating with monastic farms with an emphasis on wool production. By the end of the time range, the importance of wool in the economy was firmly established. Between the 10th and 12th Centuries, older male cattle were progressively more important to the economy and, when combined with increasing deformations to their lower limb bones, is consistent with use as draught animals; this practice wanes afterward, likely due to the increased demand for meat as evidenced by earlier culling of cattle, and to the growing role of draught horses.

These data confirm previously reported trends and clarify the timing of certain events, such as the earlier rise of sheep farming and the fluctuating use of draught cattle. The authors note that many areas of uncertainty remain to be examined by future study, including assessments of the significant variation between archaeological sites and standardizing of methods for determining the sex of ancient domesticated animals.

The authors add: “The use of an aoristic method allowed us to look at the changing use of cattle and sheep over a continuous chronology, rather than relying on artificial periods such as ‘Saxon’ or ‘high medieval’. This way we could see more clearly the shift in emphasis towards sheep husbandry in the seventh century and the peak in draught cattle use for arable production in the tenth to twelfth centuries, followed by a change in market forces requiring more meat and milk as the population grew in the thirteenth and fourteenth centuries.”

“This was a great project to work on; it followed on from the groundbreaking research produced of the Feeding Medieval England project by using the data from that project to develop a new method of analysis with David Orton. This method will allow a better understanding of changes in the animal economy over time, and there is no reason why the method cannot be expanded to include other types of archaeological data.”

“The increase in older cattle in the tenth to twelfth centuries was unexpected and implies a real change in the working practices of farmers in that period. It would have relied upon closer working relationships between people and cattle, and it is likely that they were valued members of the workforce. As far as sheep are concerned, the new monastic communities of the late seventh century appear to have instigated the increase in wool production that underpinned the English economy well into the sixteenth century.”

The freely available article in PLOS One: https://plos.io/4yiSowj

Author interview: https://plos.io/4gvrwSm

Citation: Holmes M, Orton D, Hamerow H, Thomas R (2026) Meat, milk, wool and grain: The animal economy of medieval England (CE 400 to 1400). PLoS One 21(9): e0355965. https://doi.org/10.1371/journal.pone.0355965

Hidden DNA in medieval gospels reveal history of deadly livestock virus

 

Peer-Reviewed Publication

University College Dublin

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Cambridge, Trinity College, MS B.10.5, fol. 62v, the Epistles of St Paul, Ireland/Northumbria, 700–800 CE. Reproduced with kind permission of the Master and Fellows of Trinity College Cambridge

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Credit: Cambridge, Trinity College, MS B.10.5, fol. 62v, the Epistles of St Paul, Ireland/Northumbria, 700–800 CE. Reproduced with kind permission of the Master and Fellows of Trinity College Cambridge

Some of Europe’s most well-known historic manuscripts, including the York Gospels, have proven to be biological time capsules for uncovering the 3,500-year history of the sheeppox virus (SPPV).

By extracting DNA from the animal skins used to make the documents’ centuries-old parchment, an international team of geneticists, historians, virologists, protein chemists and conservators, led by University College Dublin have provided the first genetic evidence of how this devastating disease plagued European farmers’ herds long before the modern era.

A highly contagious disease, sheeppox spreads rapidly and can affect large portions of a flock in a short time.

The disease is particularly dangerous because it can cause very high mortality rates, especially in young animals, and dramatically reduces productivity by damaging wool, meat and milk yields.

“The recording of ancient DNA of pathogens has completely changed our understanding of infectious disease in the past, and here we show that parchment can also preserve animal pathogen DNA. It is possible that archives and libraries around the world also contain the genetic traces of disease outbreaks in animals in the past,” said Louis L’Hôte, PhD candidate at UCD and lead author of the study. 

“These genomes help us understand how these pathogens evolved and how they impacted past societies - such as sheeppox virus, which we show has been affecting Eurasian sheep herds for at least three and a half millennia.”

In a new study, published in Science Advances, reconstructing over 3,500 years of sheeppox virus evolution, researchers identified traces of the disease in medieval manuscripts, including several of significant historical importance.

Among the works analysed was the 1,000-year-old York Gospels, one of the finest illuminated manuscripts surviving from the early Anglo-Saxon period, and earlier manuscripts such as the Corpus Glossary of Corpus Christi College Cambridge, one of the earliest English dictionaries, and other medieval codices from across Britain and continental Europe.

In several cases, multiple pages from the same manuscript were found to contain sheeppox virus DNA, indicating that infected animals were used in their production.

Because the parchment used in the making of these documents was made from the hides of livestock like sheep, goats, and cattle it serves as a unique bio-archive, preserving the health of the animal at the time of its death centuries ago.

One of the most unexpected findings from the new study was the detection of sheeppox virus on parchment made from calfskin and goatskin, suggesting either rare examples of cross-species infections or that there was contamination during the parchment-making process.

“Parchment making has been considered a vanishing craft, but we are beginning to understand just how much of the past it has retained. This project shows that parchments not only preserve our cultural history for hundreds of years, but also the landscape of disease in our livestock  in the medieval period,” said Dr Kevin G. Daly, Associate Professor at UCD School of Agriculture and Food Science and the study’s supervising author.

“This kind of exciting, surprising discovery is only possible when researchers from a range of disciplines come together to share their expertise and data - a generosity and trust that collaborative science depends on.”

By combining the study of manuscripts with even older samples from Bronze Age sheep teeth, the study reveals that Sheeppox has threatened livestock for over 3,700 years.

Unlike other skeletal material, teeth can preserve genetic evidence of infection over thousands of years, providing a valuable record of past outbreaks.

The research team identified the earliest known detections of sheeppox virus from dental remains recovered from ancient pastoralist settlements in the Eurasian steppe.

By comparing these ancient sequences with modern ones, they  estimate that the major lineages of capripoxviruses (sheeppox virus, goatpox virus, and lumpy skin disease virus) diverged between 11,500 and 3,700 years ago. 

This timeline aligns with the rise of animal domestication and the major translocation of sheep from the steppe into Europe.

“People around the world are still fighting against this pathogen - there is currently an outbreak of sheeppox in Greece, causing much economic damage,” said Louis L’Hôte.

“Ancient genomes can help us understand how these pathogens affecting us today evolved. We find that unlike the smallpox virus, the sheeppox virus genome was very stable over the last few millennia.”

Adding: “This might mean that genetic changes before this point were very important to how the sheeppox virus evolved to infect its host, which may help us fight the pathogen in the future.”

This study was funded by Taighde Éireann-Research Ireland and the European Research Council, and led by researchers at UCD in collaboration with over 30 Irish and international institutions including Trinity College Dublin, the Helmholtz Institute for One Health, Université Paris 1 Panthéon-Sorbonne, the University of Leicester, Cambridge University, and the University of Copenhagen.

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Journal

Science Advances

DOI

10.64898/2026.02.23.707469 

Wrapping grains in leaves: from tomb to table

Peer-Reviewed Publication

Science China Press

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image: 

The East I chamber of the Wuwangdun Tomb (A) and the plant bundle (B), note the floating plant bundles in the water surface. Phytoliths (C 1-9 and 11, 12) and pollen (C 12) from the plant bundles indicating Poaceae plant remains dominated the plant bundle. Plant seeds (D) remains illustrated the full husk condition. Specific details of phytoliths, pollen and seeds can be found in the supplementary of the article.

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Credit: Yong Ge

The research team, led by Dr. Yong Ge from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, and Dr. Fan Yang from the National Center for Archaeology, conducted systematic archaeobotanical analyses of the plant bundles unearthed from the Wuwangdun Tomb. Their findings suggest that these plant bundles may represent a possible precursor of zongzi, the well-known traditional Chinese food.

The study revealed that the plant bundles were wrapped in oak (Quercus dentata) leaves, stuffed with rice (Oryza sativa), millets (Panicum miliaceum and Setaria italica), and other cereals (species not yet determined), and bound with cordage made from grass leaves (subfamilies Panicoideae and Arundinoideae). Structurally, they are identical to modern zongzi, which are typically wrapped in bamboo (Indocalamus tessellatus) leaves, filled with glutinous rice, and tied with cordage made from Chinese iris (Iris lactea) leaves. Notably, however, the grains found in the archaeological bundles were unhulled and the bundles still contained inflorescence remains, suggesting that these bundles were not intended for consumption but rather served as funerary offerings—a key distinction from their modern counterparts.

Dated to approximately 2,200 years ago, these plant bundles fall within both the historical period of the Chu State and the same geographic region associated with the legend of Qu Yuan. According to the legend, people threw zongzi into the Miluo River—where Qu Yuan drowned himself—to prevent fish from consuming his body. This legend not only reflects the use of zongzi in commemorating the dead but also aligns remarkably well with the funerary context of the archaeological discovery.

Prior to this study, the only unequivocal archaeological evidence of typical zongzi came from a tomb dating back about 1,000 years to the Song Dynasty, with specimens nearly the same to modern ones. The Wuwangdun finds, could potentially extend the known history of zongzi by another millennium. Over this 1,000-year timespan, the structure and function of zongzi appear to have undergone a significant transformation—from ritual offerings to everyday food. In modern times, zongzi has diversified greatly: wrapping materials vary according to local resources, ranging from banana leaves to bamboo tubes, and fillings have expanded to include everything from sago to seafood. While cultural innovation has never ceased, the deep-rooted origin of this tradition may now be finally elucidated.

This discovery not only enhances our understanding of ancient funerary rituals but also bridges historical records with archaeological evidence, offering tangible proof of China's long and splendid cultural traditions.

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Journal

National Science Review

DOI

10.1093/nsr/nwag504 

 

Human-driven fires have shaped the Amazonian forest for over 10,000 years

 

Peer-Reviewed Publication

Pensoft Publishers

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a. Map of Amazonian sites with 1329 14C AMS dated charcoal fragments or burned archaeological material used in the summed probability analyses. Sites are color coded by geographic region: central (CA), eastern (EA), northwestern (WAN), southwestern (WAS), southern (SA) Amazonia, and Guiana Shield (GS). Symbols denote new 14C dates from this study (squares inside dashed boxes), and previously published 14C dates from soil charcoal surveys (circles) and archaeological surveys (triangles). Symbol size indicates the number of 14C dates at each site. Tree cover is shown as the fractional tree cover in proportions ranging from 0 to 1 for the year 2020 (Liu et al. 2024); b. Frequencies of 14C dates over the last 12,000 years for this study (left), previously published dated soil charcoal fragments from paleoecological surveys (center), or previously published dated material from archaeological sites (right).

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Credit: McMichael et al., 2026

New research is dismantling the long-standing myth of the "pristine" Amazon. A reconstruction of 10,000 years of Amazonian pyrogeography, based on 1,361 radiocarbon (¹⁴C) dates across 303 sites - including soil charcoal and burned archaeological material - shows that fire in the rainforest is almost exclusively a human-driven phenomenon, not a natural one. Over the last two millennia, human-ignited fire has driven vegetation change on a scale comparable to major climatic shifts, such as deglaciation or the extinction of Pleistocene megafauna. The research has been published in the open-access, peer-reviewed Frontiers of Biogeography journal.

The human spark

Amazonian fires rarely, if ever, ignite without human input. In the pre-human evolutionary history of these wet forests, fire was an exceptional rarity.

Glacial-aged paleoecological reconstructions from sites like the Hill of Six Lakes in Brazil and the Serra Sul dos Carajás reveal that charcoal was either entirely absent or present in only minuscule amounts before human arrival. Even more striking, the Campo Libre sediment core on the Andean slopes of Ecuador showed a total absence of fire for 30,000 years, ending only when humans appeared on the landscape around 4,500 years ago.

In their paper, the researchers, describes the arrival of humans as the introduction of fire to a "naïve landscape." Because Amazonian plants are evolutionarily fire-sensitive, the introduction of regular burning by a fire-using species fundamentally altered a system that had been stable since the late Pleistocene.

The ignition timeline

By compiling and analysing 1,361 (¹⁴C) radiocarbon-dated charcoal fragments and archaeological materials, researchers mapped a history of human-driven fire across Amazonia that unfolded over three phases of the Holocene. 

Between 10,000 and 6,000 years ago, fires were highly restricted, occurring primarily within the basin's peripheral areas and along the main channel of the Amazon River. This localised footprint shifted dramatically between 6,000 and 4,000 years ago, as the geographic spread of fire and occupation sites accelerated sharply across most regions - a development that coincided with the onset of early maize cultivation in northwestern and southwestern Amazonia. 

Finally, between 3,000 and 2,000 years ago, fire reached the deep interior of the basin: though central Amazonia had remained a relatively fire-free refuge for thousands of years while the periphery burned, it was ultimately transformed as expanding human influence and fire-use reached the very heart of the forest. 

The dying fire

This human-driven fire history is marked by a dramatic, two-phase decline over the last 700 years. 

First, an initial decrease in fire frequency 600 to 700 years ago which supports the "early abandonment" of lands several centuries before European arrival. Physical evidence from lake sediments shows a significant "pollen surge" during this window, signaling massive reforestation and a major pre-Columbian shift in land use or site abandonment.

The second and larger decline followed the "Great Dying" after A.D. 1541, when disease, warfare, and enslavement killed an estimated 90-95% of Indigenous peoples in the Americas. As ignitions vanished with the population, the forest entered a second, more extensive phase of recovery. 

The ecological legacy of 10 000 years of fire

These changing fire patterns - particularly over the last two millennia - led to an increase in human-caused fires, which spread across all regions and accelerated changes in vegetation. Ultimately, this left a profound ecological imprint that has strongly shaped today’s plant communities by selectively favoring fire-tolerant species, such as palms, over fire-sensitive vegetation.

The restructuring of Amazonian pyrogeography over the last 2,000 years has likely played a large role in shaping modern forests. The intensification of fire during this period induced rates and magnitudes of vegetation change that are comparable to major climatic shifts. The impact was subtle,  favoring species that were already there but showed the most fire tolerance, such as some palms, but this pressure has undoubtedly changed the configuration of Amazonian plant communities.

- the team explained in their research article

Citation:

McMichael CNH, Heijink BM, Witteveen NH, Zwarts A, Bush MB (2026) The pyrogeography of Amazonia: a Holocene perspective. Frontiers of Biogeography 19: e169863. https://doi.org/10.21425/fob.19.169863

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