New tool to enable exploration of human-environment interactions

Universal device will allow transdisciplinary collaboration globally

Peer-Reviewed Publication

WASHINGTON UNIVERSITY IN ST. LOUIS

 

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MULTIPLE OVERLAPPING DAHLIAGRAMS

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CREDIT: MICHAEL FRACHETTI/WASHINGTON UNIVERSITY

Spurred by the current climate crisis, there has been a heightened attention within the scientific community in recent years to how past climate variation contributed to historic human migration and other behaviors. 

Now, an international group of scientists — including archaeologists, historians, climate scientists, paleo-scientists, a volcanologist and others — are calling for a strengthened commitment to transdisciplinary collaboration to study past and present human-environmental interactions, which they say will advance our understanding of these complex, entangled histories. Their recommendations were published Nov. 22 in Science Advances. 

In doing so, the group has introduced a new tool, the “dahliagram,” to enable researchers to analyze and visualize a wide array of quantitative and qualitative knowledge from diverse disciplinary sources and epistemological backgrounds. 

“Backed by higher-resolution data concerning past climates, environmental change is increasingly seen as a crucial factor in debates concerning social, political and economic change — and human behavior generally — through time and space,” said Michael Frachetti, a professor of archaeology in Arts & Sciences at Washington University in St. Louis, and a lead author of the paper.

“Yet interdisciplinary attempts to cross data from history, climate science, archaeology and ecology to model past social-environmental interactions are challenged by mismatched units of measure and degrees of uncertainty,”

The dahliagram attempts to overcome those challenges by creating a universal and visual language to enable cross-disciplinary collaboration. Moreover, it allows researchers to compress vast amounts of data into a single, easy-to-interpret model. 

Named for the dahlia flower whose petals bloom in concentric arrays , the dahliagram’s “petals” illustrate the relative impact of different pull and push factors contributing to human behavior over time. For example, the petals could represent the climate and environment, conflicts, politics and power, technology and resource availability. These are just examples, though. One of the benefits of the tool is that it is fully customizable to meet each study’s needs. 

According to Frachetti, the tool is meant to stimulate conceptual thinking and promote critical engagement, dialogue and debate. It welcomes data from domains of research like history or archaeology that are not easily quantified as factors in understanding  behaviors like migration. And it requires the user to think beyond simply causality and consider the unique intersection of social, economic, political and environmental conditions for each case. 

“The tool not only allows for a more nuanced understanding of complex data, but also can be a ‘gut check’ — a way of testing your hypotheses and assumptions,” Frachetti said.   

Testing the dahliagram

To test the capabilities of the proposed dahliagram tool, the group created three models that assess the impacts of a range of factors on local- to large-scale mobility in three pivotal regions of world history: eastern Africa, inner Eurasia and the North Atlantic. These selected case studies range in chronological scale from decades to centuries to millennia. 

Although the dahliagram is a universal device for human-environmental research, for the purpose of this study, the researchers focused on human mobility as a behavioral response.

In each model, “movement” is placed at the center of the dahliagram while different factors are represented in a surrounding array of petals. The team synthesized volumes of research and data on each factor and then ranked it according to its influence from low to high over three concentric rings of increasing intensity. 

“One of the challenges to studying past phases of migration is that there’s very rarely a single driver. It’s usually a multitude of things that are impacting the people. Changes in the climate or access to resources could be one factor, but it’s usually accompanied by something like war, new innovations, economic or political pressures, etc. The people in the Sahara, for example, have adapted to desertification for more than 5,000 years, making a simple driver for their patterned mobility, or a discrete migratory event, rather unlikely,” Frachetti said. 

An interesting thing happened when the team compared the dahliagram models for each of the three case studies. Although they are separated historically by hundreds of years and thousands of kilometers, unexpected parallels between the cases became obvious to the team.

“Population movement within emergent empires in both Asia and East Africa appears to be rooted in similar forces of political and social identity, as well as ambitious interests to acquire regional resources and stimulate trade and connectivity,” the authors write. “Environmental factors were an omnipresent concern but appear to be outweighed by factors such as conflict and sovereignty.

“The historical implications of mobility within these formative empires in their respective era and region are unique, but only when visualized in the dahliagram do we see the shared correlations across an array of factors that may produce fruitful onward investigation into their behavioral similarities at the human-environmental nexus.” 

Overall, the group found the dahliagram to be effective in assessing population movements that occurred within richly documented historical time scales, as well as over long periods of time. 

“We now hope that our new dahligram approach will be applied by many scholars from different fields across the natural and social sciences and the humanities to enhance interdisciplinary investigations into the entanglements between nature and humans,”  said Ulf Büntgen, a professor of environmental systems analysis in the Department of Geography at University of Cambridge, U.K., and a lead author of the paper. 

Inspired by and built for transdisciplinary research

In recent years, the academic community has embraced the concept of transdisciplinary research. Like interdisciplinary or multidisciplinary research, transdisciplinary research connects scholarship from various disciplines to more fully grasp the complexity of problems and enable creative problem solving and discovery. What makes transdisciplinary research unique is that it incorporates the perspectives of non-academic stakeholders, including members of tribes and ethnic groups, historians, artists and other subject-matter experts. 

Translating and effectively communicating complicated findings and uncertainties across disciplines, and with non-academic stakeholders, is not without its challenges, though. In fact, the idea for the dahliagram was inspired by the group’s ongoing transdisciplinary work in the “Volcanoes, Climate and History” project, which was convened by Ulf Büntgen and Clive Oppenheimer from the University of Cambridge and supported by The Center for Interdisciplinary Research (ZiF: Zentrum für interdisziplinäre Forschung) at Bielefeld University in Germany.

The dahliagram not only enables researchers to synthesize data from various sources with different metrics, it also helps ensure equity among the various contributors, Frachetti said. Moreover, the visual nature of the dahliagram is especially helpful when communicating with various stakeholders. 

“This tool allows us to gather communities of specialists and fairly and collectively express our knowledge in a way that that is on equal footing, rather than allowing one discipline to lead the way. I think that that kind of equity is a significant component of what the dahliagram provides,” he said.

Ultimately, the team hopes the dahliagram will be adopted within the scientific community to stimulate further explorations of complex human behaviors by leveraging multidisciplinary team building and consensus. 

According to Nicola Di Cosmo, a historian and Luce Foundation professor in East Asian Studies at the Institute for Advanced Study in Princeton, NJ and co-author of the study, the addition of the dahliagram will expand the analytical tools available for historical research.

“Historians may be encouraged to use the dahliagram to translate into a visual representation a wealth of data from multiple sources and different disciplines and thus avoid monocausal explanations derived from limited datasets,” he said.

As for scientists, Frachetti said that some might initially have hesitations about the tool because it does not provide hard facts, but he hopes the community will come to appreciate the tool for what it does provide: a visualization of the facts.

“The dahliagram is a contextual tool that’s meant to help you question your assumptions and consider other explanations. And that’s really important because even our best ‘hard facts’ — things like tree rings and our measurements to monitor the planet’s health — are conditioned by assumptions and uncertainty.”

In addition to Frachetti and Büntgen, the following experts contributed to this paper: Nicola Di Cosmo, Institute for Advanced Study; Jan Esper, Johannes Gutenberg University; Lamya Khalidi, Université Côte d’Azur CNRS, CEPAM; Franz Mauelshagen, University of Bielefeld; Clive Oppenheimer, University of Cambridge; and Eleonora Rohland, University of Bielefeld. 

Dahliagram time-series modeling human movement in east Africa/southern Arabia over the past ~10,000 years.

Dahliagram time-series modeling human movement in Inner Eurasia over the past ~5,000 years.

Dahliagram time-series modeling human movement in the North Atlantic region over the past ~1500 years.

 

CREDIT

Michael Frachetti/Washington University

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JOURNAL

Science Advances

DOI

10.1126/sciadv.adj3142 

METHOD OF RESEARCH

Case study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The Dahliagram: An interdisciplinary tool for investigation, visualization, and communication of past human-environmental interaction

ARTICLE PUBLICATION DATE

22-Nov-2023

'Dolomite Problem': 200-year-old geology mystery resolved

To build mountains from dolomite, a common mineral, it must periodically dissolve. This counter-intuitive lesson could help make new defect-free semiconductors and more.

Peer-Reviewed Publication

UNIVERSITY OF MICHIGAN

Images // Video

ANN ARBOR—For 200 years, scientists have failed to grow a common mineral in the laboratory under the conditions believed to have formed it naturally. Now, a team of researchers from the University of Michigan and Hokkaido University in Sapporo, Japan have finally pulled it off, thanks to a new theory developed from atomic simulations.

Their success resolves a long-standing geology mystery called the "Dolomite Problem." Dolomite—a key mineral in the Dolomite mountains in Italy, Niagara Falls, the White Cliffs of Dover and Utah's Hoodoos—is very abundant in rocks older than 100 million years, but nearly absent in younger formations.

"If we understand how dolomite grows in nature, we might learn new strategies to promote the crystal growth of modern technological materials," said Wenhao Sun, the Dow Early Career Professor of Materials Science and Engineering at U-M and the corresponding author of the paper published today in Science.

The secret to finally growing dolomite in the lab was removing defects in the mineral structure as it grows. When minerals form in water, atoms usually deposit neatly onto an edge of the growing crystal surface. However, the growth edge of dolomite consists of alternating rows of calcium and magnesium. In water, calcium and magnesium will randomly attach to the growing dolomite crystal, often lodging into the wrong spot and creating defects that prevent additional layers of dolomite from forming. This disorder slows dolomite growth to a crawl, meaning it would take 10 million years to make just one layer of ordered dolomite.

Luckily, these defects aren't locked in place. Because the disordered atoms are less stable than atoms in the correct position, they are the first to dissolve when the mineral is washed with water. Repeatedly rinsing away these defects—for example, with rain or tidal cycles—allows a dolomite layer to form in only a matter of years. Over geologic time, mountains of dolomite can accumulate.

To simulate dolomite growth accurately, the researchers needed to calculate how strongly or loosely atoms will attach to an existing dolomite surface. The most accurate simulations require the energy of every single interaction between electrons and atoms in the growing crystal. Such exhaustive calculations usually require huge amounts of computing power, but software developed at U-M's Predictive Structure Materials Science (PRISMS) Center offered a shortcut.

"Our software calculates the energy for some atomic arrangements, then extrapolates to predict the energies for other arrangements based on the symmetry of the crystal structure," said Brian Puchala, one of the software's lead developers and an associate research scientist in U-M's Department of Materials Science and Engineering. 

That shortcut made it feasible to simulate dolomite growth over geologic timescales.

"Each atomic step would normally take over 5,000 CPU hours on a supercomputer. Now, we can do the same calculation in 2 milliseconds on a desktop," said Joonsoo Kim, a doctoral student of materials science and engineering and the study's first author.

The few areas where dolomite forms today intermittently flood and later dry out, which aligns well with Sun and Kim's theory. But such evidence alone wasn't enough to be fully convincing. Enter Yuki Kimura, a professor of materials science from Hokkaido University, and Tomoya Yamazaki, a postdoctoral researcher in Kimura's lab. They tested the new theory with a quirk of transmission electron microscopes.

"Electron microscopes usually use electron beams just to image samples," Kimura said. "However, the beam can also split water, which makes acid that can cause crystals to dissolve. Usually this is bad for imaging, but in this case, dissolution is exactly what we wanted."

After placing a tiny dolomite crystal in a solution of calcium and magnesium, Kimura and Yamazaki gently pulsed the electron beam 4,000 times over two hours, dissolving away the defects. After the pulses, dolomite was seen to grow approximately 100 nanometers—around 250,000 times smaller than an inch. Although this was only 300 layers of dolomite, never had more than five layers of dolomite been grown in the lab before.

The lessons learned from the Dolomite Problem can help engineers manufacture higher-quality materials for semiconductors, solar panels, batteries and other tech.

"In the past, crystal growers who wanted to make materials without defects would try to grow them really slowly," Sun said. "Our theory shows that you can grow defect-free materials quickly, if you periodically dissolve the defects away during growth."

The research was funded by the American Chemical Society PRF New Doctoral Investigator grant, the U.S. Department of Energy and the Japanese Society for the Promotion of Science.
Study: Dissolution enables dolomite crystal growth near ambient conditions (DOI: 10.1126/science.adi3690)

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JOURNAL

Science

DOI

10.1126/science.adi3690 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Dissolution enables dolomite crystal growth near ambient conditions

ARTICLE PUBLICATION DATE

23-Nov-2023

Dolomite crystals require cycles of saturation conditions to grow

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Addressing the long-standing “dolomite problem,” an oddity that has vexed scientists for nearly 200 years, researchers report that dolomite crystals require cycling of saturation conditions to grow. The findings provide new insights into how dolomite is formed and why modern dolomite is primarily found in natural environments with pH or salinity fluctuations. Dolomite – a calcium magnesium carbonate – is one of the major minerals in carbonate rocks, accounting for nearly 30% of the sedimentary carbonate minerality in Earth’s crust. However, despite its geological abundance, dolomite does not readily grow under laboratory conditions, hindering the study of the mineral. For two centuries, scientific efforts have failed to precipitate dolomite in the laboratory near ambient conditions. The apparent contradiction between the massive deposits of dolomite in nature and its inability to grow even in supersaturated solutions under ambient conditions has resulted in the so-called dolomite problem. Here, using atomistic simulations of dolomite, Joonsoo Kim and colleagues make a discovery that informs this issue. Kim et al. used density function theory and kinetic Monte Carlo crystal growth simulations to show that cycles of saturation conditions are needed to promote dolomite crystal growth in the laboratory. According to the simulation’s predictions, frequent cycling of a solution between supersaturation and undersaturation can speed up dolomite growth by up to 10 million times – a process that may be paramount for producing the large amounts of dolomite on Earth’s surface. The authors validated their predictions using a transmission electron microscope to observe bulk dolomite crystal growth in situ under fluctuating saturation conditions. “The findings of Kim et al. raise many questions about how geochemical fluctuations occur in the natural world over geological timescales and what factors influence the process,” writes Juan Manuel García-Ruiz in a related Perspective.

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JOURNAL

Science

DOI

10.1126/science.adi3690 

ARTICLE TITLE

Dissolution enables dolomite crystal growth near ambient conditions

ARTICLE PUBLICATION DATE

24-Nov-2023

 

The Fens of eastern England once held vast woodlands, study finds

Peer-Reviewed Publication

UNIVERSITY OF CAMBRIDGE

 

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SCIENTISTS FROM THE UNIVERSITY OF CAMBRIDGE STUDIED HUNDREDS OF TREE TRUNKS, DUG UP BY FENLAND FARMERS WHILE PLOUGHING THEIR FIELDS. THE TEAM FOUND THAT MOST OF THE ANCIENT WOOD CAME FROM YEW TREES THAT POPULATED THE AREA BETWEEN FOUR AND FIVE THOUSAND YEARS AGO.

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CREDIT: TATIANA BEBCHUK

The Fens of eastern England, a low-lying, extremely flat landscape dominated by agricultural fields, was once a vast woodland filled with huge yew trees, according to new research.

Scientists from the University of Cambridge studied hundreds of tree trunks, dug up by Fenland farmers while ploughing their fields. The team found that most of the ancient wood came from yew trees that populated the area between four and five thousand years ago.

These trees, which are a nuisance when they jam farming equipment during ploughing, contain a treasure trove of perfectly preserved information about what the Fens looked like thousands of years ago.

The Fen yew woodlands suddenly died about 4,200 years ago, when the trees fell into peat and were preserved until today. The researchers hypothesise that a rapid sea level rise in the North Sea flooded the area with salt water, causing the vast woodlands to disappear.

The climate and environmental information these trees contain could be a valuable clue in determining whether this climate event could be related to other events that happened elsewhere in the world at the same time, including a megadrought in the Middle East that may have been a factor in the collapse of ancient Egypt’s Old Kingdom. Their results are reported in the journal Quaternary Science Reviews.

Yew (Taxus baccata) trees are one of the longest-lived species in Europe, and can reach up to 20 metres in height. While these trees are fairly common in Cambridge College gardens and churchyards across southern England, they are absent in the Fens, the low-lying marshy region of eastern England. Much of the Fens was a wetland until it was drained between the 17th and 19th centuries using artificial drainage and flood protection. Today, the area is some of the most productive farmland in the UK, thanks to its rich peat soil.

While the area is great for farming and does have its own charms, few people would describe the Fens as spectacular: for the most part, the area is extremely flat and dominated by fields of potatoes, sugar beet, wheat and other crops. But five thousand years ago, the area was a huge forest.

“A common annoyance for Fenland farmers is getting their equipment caught on big pieces of wood buried in the soil, which can often happen when planting potatoes, since they are planted a little deeper than other crops,” said lead author Tatiana Bebchuk, a PhD student from Cambridge’s Department of Geography. “This wood is often pulled up and piled at the edge of fields: it’s a pretty common sight to see these huge piles of logs when driving through the area.”

For farmers, these logs are a nuisance. But for Bebchuk and her colleagues, they are buried treasure. The Cambridge team approached several Fenland farmers and took samples of hundreds of logs that had been dug up and discarded, to find out what secrets they might hold.

“I remember when I first saw this enormous pile of abandoned trees, it was incredible just how many there were,” said Bebchuk. “But when we got them back to lab, we were even more surprised: these trees were so well-preserved, it looked as if they were cut down just yesterday.”

To put current anthropogenic climate change in a long-term context of natural variability, scientists need accurate evidence from the past, and trees are some of the best recorders of past conditions: their annual growth rings contain information about temperature and hydroclimate for every growing season they witnessed. “But the further back in time we go, the less reliable evidence we have, since very old trees and well-preserved wood materials are extremely rare,” said Professor Ulf Büntgen, the senior author of the study.

However, analysis by the Cambridge Tree-Ring Unit (TRU) showed that the yew trees dug up from Fenland fields were very old indeed: some of these ancient trees were 400 years old when they died. The new find provides unique climate information for over a millennium from around 5,200 years ago until about 4,200 years ago, when much of the Fens was a woodland of yew and oak: completely different than it looks today.

“Finding these very old trees in the Fens is completely unexpected – it would be like turning a corner in rural Cambridgeshire and seeing an Egyptian pyramid – you just wouldn’t expect it,” said Bebchuk. “It’s the same with nature – wood rots and decomposes easily, so you just don’t expect a tree that died five or four thousand years ago to last so long.”

Given that most of the Fens are barely above sea level, about 4,200 years ago, a sudden rise in sea level most likely killed the Fen woodlands. The period that the Fen woodlands died coincided with major climatic changes elsewhere in the world: at roughly the same time, a megadrought in China and the Middle East was a possible trigger of the collapse of several civilisations, including Egypt’s Old Kingdom and the Akkadian Empire in Mesopotamia.

“We want to know if there is any link between these climatic events,” said Bebchuk. “Are the megadroughts in Asia and the Middle East possibly related to the rapid sea level rise in northern Europe? Was this a global climate event, or was it a series of unrelated regional changes? We don’t yet know what could have caused these climate events, but these trees could be an important part of solving this detective story.”

“This is such a unique climate and environmental archive that will provide lots of opportunities for future studies, and it’s right from Cambridge’s own backyard,” said Büntgen. “We often travel all over the world to collect ice cores or ancient trees, but it’s really special to find such a unique archive so close to the office.”

 

The Fens of eastern England, a low-lying, extremely flat landscape dominated by agricultural fields, was once a vast woodland filled with huge yew trees, according to new research. Scientists from the University of Cambridge studied hundreds of tree trunks, dug up by Fenland farmers while ploughing their fields. The team found that most of the ancient wood came from yew trees that populated the area between four and five thousand years ago.

Inner part of the pile of subfossil yew trunks. Note fresh chain-saw cuts after sampling cross-sectional discs.

Cross-section of a subfossil yew trunk after surface preparation. The disc contains 380 tree-rings, i.e the tree was at least 380 years old when it died.

CREDIT

Tatiana Bebchuk

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JOURNAL

Quaternary Science Reviews

DOI

10.1016/j.quascirev.2023.108414 

ARTICLE TITLE

Sudden disappearance of yew (Taxus baccata) woodlands from eastern England coincides with a possible climate event around 4.2 ka ago

ARTICLE PUBLICATION DATE

24-Nov-2023

 

How do plants determine where the light is coming from ?

Peer-Reviewed Publication

UNIVERSITY OF LAUSANNE

Plants have no visual organs, so how do they know where light comes from? In an original study combining expertise in biology and engineering, the team led by Prof Christian Fankhauser at UNIL, in collaboration with colleagues at EPFL, has uncovered that a light-sensitive plant tissue uses the optical properties of the interface between air and water to generate a light gradient that is 'visible' to the plant. These results have been published in the journal Science.

The majority of living organisms (micro-organisms, plants and animals) have the ability to determine the origin of a light source, even in the absence of a sight organ comparable to the eye. This information is invaluable for orienting oneself or optimal positioning in the environment. Perceiving where light is coming from is particularly important for plants, which use this information to position their organs, a phenomenon known as phototropism. This enables them to capture more of the sun's rays, which they then convert into chemical energy through the process of photosynthesis, a vital process which is necessary for the production of nearly all of the food we eat.

Although the photoreceptor that initiates phototropism has long been known, the optical properties of photosensitive plant tissue have until now remained a mystery. A multidisciplinary study published in Science, combining the expertise of the teams of DrSc. Christian Fankhauser (full professor and director of the Integrative Genomics Centre in the Faculty of Biology and Medicine at UNIL), DrSc. Andreas Schüler (head of the Nanotechnology for Solar Energy Conversion group at EPFL's Solar Energy and Building Physics Laboratory) and UNIL's Electron Microscopy Centre uncovered a surprising tissue feature allowing plants to detect directional light cues.

"It all started with the observation of a mutant of the model species Arabidopsis thaliana, the thale cress, whose stem was surprisingly transparent", explains Christian Fankhauser, who led the research. These plants failed to respond to light correctly. The UNIL biologist then decided to call on the skills of his colleague Andreas Schüler from EPFL, in order to further compare the specific optical properties of the mutant versus wild type samples. "We found that the natural milky appearance of the stems of young wild plants was in fact due to the presence of air in intercellular channels precisely located in various tissues. In the mutant specimens, the air is replaced by an aqueous liquid, giving them a translucent appearance", continues the researcher.

But what purpose do such air-filled channels serve? They enable the photosensitive stem to establish a light gradient that can be "read" by the plant. The plant can then determine the origin of the light source. This phenomenon is due to the different optical properties of air and water, which make up the majority of living tissue. “More specifically, air and water have different refractive indices. This leads to light scattering as it passes through the seedling. We have all observed this phenomenon when admiring a rainbow", explains Martina Legris, a postdoctoral fellow in Prof Fankhauser's group and co-first author of the study.

Thanks to their research, the scientists have revealed a novel mechanism that enables living organisms to perceive where the light is coming from, enabling them to position their organs such as leaves in a way that optimizes light capture for photosynthesis. The study also provided a better understanding of the formation of air-filled intercellular channels, which have a range of functions in plants, in addition to the formation of light gradients. Among other uses, these channels promote gas exchange and also make it possible to resist hypoxia (reduction in the quantity of oxygen) in the event of flooding. Their development from the embryonic stage to adulthood, is still very poorly understood. Genetic resources used in this study will be useful to better understand the formation and maintenance of these intriguing structures.

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JOURNAL

Science

DOI

10.1126/science.adh9384 

ARTICLE TITLE

Air channels create a directional light signal to regulate hypocotyl phototropism

ARTICLE PUBLICATION DATE

24-Nov-2023

 

How do temperature extremes influence the distribution of species?

McGill biology researchers found that there are patterns regarding the importance of temperature in determining where species live, shedding light on their sensitivity to climate change

Peer-Reviewed Publication

MCGILL UNIVERSITY

As the planet gets hotter, animal and plant species around the world will be faced with new, potentially unpredictable living conditions, which could alter ecosystems in unprecedented ways. A new study from McGill University researchers, in collaboration with researchers in Spain, Mexico, Portugal, Denmark, Australia, South Africa and other universities in Canada, investigates the importance of temperature in determining where animal species are currently found to better understand how a warming climate might impact where they might live in the future.

To find out, the researchers tested the role of temperature as a factor that could limit a species’ potential habitat range. They compared the temperatures and areas where 460 cold-blooded animal species currently live to the temperatures and areas where they could live based on their tolerance to temperatures.

They found that, unlike species living in the ocean, land animals such as reptiles, amphibians and insects have habitat ranges that are less directly impacted by temperature. The higher a species is in latitude, the lower its tendency to live in areas near the equator with temperatures they could tolerate, the researchers say. This means that, instead of tolerance to temperature, negative interactions with other species – like with competitors or parasites – could be what keep these species away from this potential habitat.

“It was not surprising to find that temperature doesn’t always limit species ranges, but what was surprising was that, despite the complexity, we found general patterns in the role that temperature plays across species,” said lead author of the study published in Nature Ecology & Evolution and PhD student in the Department of Biology, Nikki A. Moore.

“This research helps us to understand general patterns in how sensitive the distributions of different cold-blooded animal species might be to changes in temperature, which will help us to predict how the global distribution of species will change because of climate change.”

A pattern that predicts species distribution

The pattern that Moore and colleagues found helps resolve two conflicting hypotheses about the distribution of life on earth.

“While it had long been thought that species ranges are less limited by temperature and more limited by species interactions in the tropics, the new work shows that higher-latitude species are increasingly excluded from their potential ranges in the tropics, supporting the idea of a trade-off between broad thermal tolerances and performance in the tropics,” said Moore.

While these results provide insights into the sensitivities of species in different realms and across latitudes to climate change, the next step for this research is to test these predictions using actual observations of species range shifts, the researchers say.

The researchers say predicting and testing how species distributions respond to temperature requires on good observations of where species live. Anyone can get involved in contributing to our knowledge of species distributions through citizen science, using applications such as iNaturalist.

About the study

Temperate species underfill their tropical thermal potentials on land by Nikki A. Moore et al., was published in Nature Ecology and Evolution.

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JOURNAL

Nature Ecology & Evolution

DOI

10.1038/s41559-023-02239-x 

ARTICLE TITLE

Temperate species underfill their tropical thermal potentials on land.