It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, January 28, 2022
Post-mortem interval of human skeletal remains accurately determined by means of non-destructive techniques
The UPV/EHU-University of the Basque Country is developing a useful, versatile model to accurately determine the post-mortem interval (PMI)
IMAGE: THE RESEARCHERS OF THE UNIVERSITY OF THE BASQUE COUNTRY LUIS BARTOLOMÉ AND ALFREDO SARMIENTO.view more
CREDIT: JORGE NAVARRO. UPV/EHU.
In the field of forensic analysis there is a significant demand for objectively determining the post-mortem interval (PMI) when human skeletal remains are discovered. So far, a whole range of techniques have been used to establish the approximate time that has elapsed since the death of the individual, but they have significant drawbacks in terms of reliability and accuracy: they provide an approximate interval but not an exact date; they are relatively invasive techniques, which require staining or removal of a part of the bone, etc.
"The aim of this research was precisely to come up with a method capable of determining the relatively accurate post-mortem interval in human remains by using non-destructive measurements," said Luis Bartolomé, technician in the UPV/EHU’s SGIker Central Analysis Service (SCAB).
So "we analysed a set of 53 actual human skeletal remains with a known post-mortem interval provided by the Department of Legal Medicine, Toxicology and Physical Anthropology of the University of Granada. Using actual samples for the first time, we built and validated a model by combining two non-destructive tools: Raman spectroscopy and chemometrics", explained the author of the paper.
“Raman spectra," Bartolomé went on to explain, "contain physico-chemical information on nearly all the components of the sample; however, due to their complexity, in most cases it is not possible to differentiate between all the information they contain. Chemometrics is capable of extracting the parameters of interest from the spectra through mathematical and statistical methods".
"By combining both techniques, we have been able to build a model in which the Raman spectrum of each set of skeletal remains analysed is associated with a post-mortem interval. Relating the spectrum to a time interval is no easy task and for this we used statistical models and logarithms that allow us to relate each spectrum to a time. So when we receive human skeletal remains for which we don't know the time that has elapsed since death, what we do is an interpolation by inserting these data into the validated model, and that way a relatively accurate post-mortem interval can be obtained," explained Luis Bartolomé. "The data recorded in the model developed provides valuable, potentially useful, versatile information," he stressed.
According to the UPV/EHU researcher, "the combination of both techniques is a significant achievement for forensic medicine and anthropology. However, there is always room for improvement as these types of models perform better the more samples there are and the more varied they are; the model includes more heterogeneity and responds more robustly to a wider range of cases.”
Estimation of the post-mortem interval of human skeletal remains using Raman spectroscopy and chemometrics
ARTICLE PUBLICATION DATE
29-Oct-2021
A game changer in water electrolysis technology for production of green hydrogen energy
The novel high-performance anion exchange membrane water electrolyzers (AEMWEs) technology offsets the disadvantage of the high cost in the conventional water electrolysis technology
IMAGE: SCHEMATIC DIAGRAM OF THE AEMWE, WHERE THE CATALYST LAYER CONSISTS OF IONOMERS AND CATALYSTSview more
CREDIT: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY(KIST)
In recent times, hydrogen has drawn significant attention as a potential clean energy resource as an alternative to fossil fuels. In particular, there has been active research and development of water electrolysis technology that extracts hydrogen from water to produce green energy and avoids the emission of greenhouse gases. The proton exchange membrane water electrolyzer (PEMWE) technology, which is currently present in some handful of advanced countries holds core material technology and uses expensive noble metal-based catalysts and perfluorocarbon-based proton exchange membranes. Such technology results in high costs of system manufacturing. To address these limitations of the conventional technology, a research team in Korea has recently developed core technology for the next-generation water electrolysis system that has significantly improved the durability and performance while significantly lowering the cost of producing green hydrogen energy.
Korea Institute of Science and Technology (KIST, President Yoon, Seok-Jin) announced the project under the joint research between the research team of Dr. So Young Lee at the Center for Hydrogen and Fuel Cell Research and under Prof. Young Moo Lee of the Department of Energy Engineering, Hanyang University, a membrane electrode assembly (MEA) for anion exchange membrane water electrolyzers (AEMWE) was developed that is expected to replace the costly existing PEMWE technology.
AEMWE, which uses an anion exchange membrane and electrode binder, does not rely on the expensive platinum group-metal electrodes and replaces the separator plate material of the water electrolysis cell with iron instead of titanium. When comparing the price of catalyst and separator material alone, the manufacturing cost is reduced by approximately 3,000 times that of the existing PEMWE. However, it has not been commercially utilized owing to its low performance compared to that of the PEMWEs and durability issues of less than 100 h of sustained operation.
The research team developed poly(fluorenyl-co-aryl piperidinium) (PFAP)-based anion exchange materials (electrolyte membrane and electrode binder) with high ion conductivity and durability under alkaline conditions by increasing the specific surface area within the structure and based on this technology, a membrane electrode assembly was developed. The developed material represented excellent durability of more than 1,000 h of operation and has achieved a new record cell performance of 7.68 A/cm2. This is about six times the performance of existing anion exchange materials and about 1.2 times that of the expensive commercial PEMWE technology (6 A/cm2).
The technology has overcome the performance and durability issues of the core materials pointed out as limitations in the AEMWE technology to date and has raised the quality of the technology to such a level that allows replacement of the PEMWE technology. In addition to the excellent performance and durability, the commercialization of the developed anion exchange membrane materials has been underway with the incorporation of large-capacity and large-area applications.
Dr. So Young Lee of KIST commented, "Our team has developed a material and high-efficiency technology that goes beyond the limitations of the existing water electrolysis technology. This technology is expected to lay the foundation for introducing the next-generation water electrolysis technology that allows a significant reduction of the cost involved in the green hydrogen production." Professor Young Moo Lee of Hanyang University commented, "The developed material has a high potential for application as a core material for not only water electrolysis but also for the hydrogen fuel cells, carbon capture utilization and direct ammonia fuel cells, which are the next-generation hydrogen industry."
CAPTION
A graphic image of a high-performance and high-durability next-generation AEMWE device that produces green hydrogen by receiving electricity from renewable energy.
CREDIT
Korea Institute of Science and Technology(KIST)
USAGE RESTRICTIONS
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Korea Institute of Science and Technology(KIST), founded as the first multidisciplinary government-funded research institute in Korea, established a national development strategy based on science and technology and disseminated various essential industrial technologies. Now, half a century later, KIST is elevating Korea's status in the field of science and technology through world-leading fundamental technology R&D. Looking to the future, KIST will continue to strive to be a premier research institute, pursuing a brighter future of human.
This research was supported by the Ministry of Science and ICT (Minister Lim Hyesook) and was conducted as one of the institutional research program of KIST and the material-components technology development project of the Korea Evaluation Institute of Industrial Technology. The research was published in the recent issue of 'Energy & Environmental Science' (IF: 38.532, JCR top 0.182%).
IMAGE: ENGINEERING PROFESSOR JAY KAPAT LEADS THE TEAM. KAPAT IS A RECOGNIZED EXPERT IN ENERGY RESEARCH. HE LEADS CATER, WHICH HAS BROUGHT TOGETHER EXPERTS WHO ARE SOLVING SOME OF THE MOST COMPLEX RESEARCH PROBLEMS IN TURBOMACHINERY FOR POWER GENERATION, AVIATION, AND SPACE PROPULSION. KAPAT HAS MULTIPLE DEGREES INCLUDING A DOCTORATE IN MECHANICAL ENGINEERING FROM MASSACHUSETTS INSTITUTE OF TECHNOLOGY. HE IS A FELLOW OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS, AND AN AMERICAN INSTITUTE OF AERONAUTICS AND ASTRONAUTICS ASSOCIATE FELLOW. HE JOINED UCF IN 1997 AND HAS PUBLISHED MORE THAN 350 ARTICLES, MANY OF WHICH ARE HIGHLY CITED BY RESEARCHERS AROUND THE WORLD.view more
CREDIT: UCF/KAREN NORUM
The University of Central Florida (UCF) is developing new technology that is expected to make airplane engines emission free, potentially revolutionizing the aviation industry.
UCF put together a team of experts and stakeholders to evaluate their innovation, which aims to not only make aviation fuel green, but also create engines and fueling systems that easily integrate into current airport infrastructure thus saving airports and aircraft manufacturers millions of dollars as they look to retrofit.
“We don’t want to create something that will be too cumbersome and expensive to implement,” says lead investigator and UCF Engineering Professor Jay Kapat. “If we want people to adopt this green tech, it needs to be scalable. To adopt hydrogen, for example, we can’t expect every airport to set up large cryogenic liquid hydrogen systems like Kennedy Space Center. That’s unreasonable.”
With this practical approach, Kapat put together a team of experts from UCF, Georgia Tech and Purdue and with industry experts from Boeing, General Electric, ANSYS, Southwest Research Institute and the Greater Orlando Aviation Authority. The team landed a $10 million five-year NASA University Leadership Initiative grant to get the ball rolling.
“We have a good concept,” Kapat says. “And by having our partners in industry we know we’ll fine tune and be ready for technology transition, so we can provide a greener future for our children.”
The Tech
Kapat and several of his UCF colleagues in engineering and the Florida Space Institute propose using liquid ammonia (NH3) as the fuel for aircraft which, upon combustion, will produce harmless emissions that are green while still providing enough power to keep the aircraft aloft. At high altitudes ammonia is naturally liquid thereby limiting the need for special handling. Airports and airplanes are expected to store the ammonia in fuel tanks. Ammonia is commonly used as a fertilizer and, when mixed with water, in some household cleaners.
Ammonia will be the hydrogen carrier, which will be catalytically “cracked” to release nitrogen and hydrogen. The hydrogen will be burned in the onboard combustors (inside the engine) to provide the power. Airports and aircraft are expected to store the NH3 in fuel tanks. Excess NH3 will then be used to catalytically reduce any NOx left in the exhaust converting it to nitrogen and water.
When the hydrogen is released, there will be an added bonus, Kapat explained. The conversion process also provides cooling, which can be used to keep engines from overheating and burning out. The impact may be better engine performance and efficiency. Engine exhaust heat is then converted back to electricity for onboard use, thus reducing power draw from the core engines.
The team also is developing new components for jet engines to be used in conjunction with the new fuel. The team is using the 737-8 class for a baseline as it represents nearly a quarter of all commercial aircraft, according to Boeing.
The Team
“This project would not have been possible without our internal and external partners,” Kapat says.
Catalyst development and improvement of known catalysis pathways are key to the UCF effort and will be undertaken in Professor Richard Blair’s laboratory at the Florida Space Institute. Engineering Professor Subith Vasu will lead the efforts to design tools, computer models, and combustion testing from his lab. Professor Kapat will lead a team that will conduct thermal management and system integration at UCF’s Center for Advanced Turbomachinery and Energy Research (CATER), which he leads. UCF Chemical Safety and Security Coordinator Sandra Hick will oversee safety and occupational health issues that are central to any use of ammonia and hydrogen. Georgia Tech will provide its aviation simulation expertise and Purdue is providing some of its unique labs and expertise in combustion and aerodynamics. Boeing is providing the integration know-how to the aircraft, and GE is contributing its knowledge of the jet engines. Other industry partners are advising on large scale simulation, the feasibility of the technology in the real world and providing a pathway for technology transition. Student training and workforce development are also key aspects of the overall project. Several UCF students working under faculty in the various labs will contribute to the research.
The UCF team includes:
Vasu, an expert in spectroscopy, propulsion combustion and optical diagnostics
Blair, an expert in energy efficient catalytic processing of bio-derived compounds for fuels and chemical feedstock
Hick, chemical safety and security coordinator for UCF Environmental Health and Safety.
Hans-Jürgen Kiesow, a courtesy professor in CATER at UCF. A retired Siemens vice president who over saw gas turbines design and development, and management of complex global teams.
Erik Fernandez, a research assistant professor in Engineering
Terrence Meyer, Guillermo Paniagua form Purdue University
Dimitri Marvis and Jonathan Gladin from Georgia Institute of Technology
Greg Natsui, ’10 ’12 MS ’15PhD and Keith McManus from GE
Michael Stoia, Kevin Jui and Nickolas Applegate from Boeing
Swati Saxena from ANSYS
Joshua Schmitt‘15MS, Tim Allison and Grant Musgrove from the Southwest Research Institute
Kevin Thompson from the Greater Orlando Aviation Authority.
Kapat is recognized expert in energy research. He leads CATER, which has brought together experts who are solving some of the most complex research problems in turbomachinery for power generation, aviation, and space propulsion. Kapat has multiple degrees including a doctorate in mechanical engineering from Massachusetts Institute of Technology. He is a Fellow of the American Society of Mechanical Engineers, and an American Institute of Aeronautics and Astronautics Associate fellow. He joined UCF in 1997 and has published more than 350 articles, many of which are highly cited by researchers around the world.
The University of Central Florida is a metropolitan public research university in Orlando. Founded in 1963, UCF and its colleges offer more than 220 degreesfrom the university’s main campus, downtown campus, hospitality campus, health sciences campus, online and through multiple regional locations. The university benefits from a diverse faculty, staff and student body who create a welcoming environment and thrive on the opportunity to learn, discover and transform lives. Learn more at ucf.edu.
21st Century Jobs in Healthcare, Education, Space and Defense will require modeling and simulation talent
$1M Department of Education Grant to create modeling and simulation pipeline in Florida
IMAGE: PROFESSOR ROGER AZEVEDO IS THE LEAD INVESTIGATOR ON THE GRANT. HE SPECIALIZES IN INTELLIGENT SYSTEM DESIGN — THE INTERSECTION OF INTELLIGENT MACHINES AND HOW HUMANS USE THEM.view more
CREDIT: UCF/KAREN NORUM
Many of tomorrow’s jobs haven’t been imagined yet, but those well versed in cutting-edge technologies, such as modeling and simulation will have the competitive edge.
UCF’s School of Modeling, Simulation and Training (SMST) is already a national leader in modeling and simulation research and education. The Department of Defense employs many of our doctoral graduates as do a range of commercial companies. Now, thanks to a Department of Education $1 million grant, UCF will strengthen its existing graduate program, create a new undergraduate modeling and simulation curriculum and launch outreach programs for high schools, all to create a pipeline of talent that will help lead the nation in this exploding area of innovation.
“It is essential to build a future workforce with the critical skills and competencies in modeling and simulation so that we retain our competitiveness in national security and space,” says Grace Bochenek, the school’s director and a co-investigator on the grant. “The new skills are going to be necessary across many industries from security and space to education and healthcare.”
Congress declared modeling and simulation a National Critical Technology as early as 2007. It has only become more important since then as the technology has advanced. At UCF, modeling and simulation research has helped train firefighters, co-pilots, fighter pilots, law enforcement, teachers, clinicians and military medics, among others. There’s also ongoing research using simulation that focuses on teams that will travel together on long missions to other planets and asteroids.
Even some of the most popular video games kids are playing are simulations —Fortnite, Halo, etc. One of the hottest holiday toys of 2021 was the Oculus, a virtual reality home system that transports users into a simulated world.
“We can’t lose sight of the human element in the design and use of intelligent machines for training and education,” says SMST Professor Roger Azevedo, the lead investigator on the grant. He specializes in intelligent system design — the intersection of intelligent machines and how humans use them.
Part of Azevedo’s work will focus on ensuring the new courses and curriculum developed accounts for the human element. The new courses and curriculum will take into consideration the role of cognitive, metacognitive, affective, and motivational self-regulatory processes during learning with advanced learning technologies, which is Azevedo’s area of expertise. He focuses on understanding the complex interactions between humans and intelligent learning systems by using interdisciplinary methods to measure cognitive, metacognitive, emotional, motivational, and social processes and their impact on learning, reasoning, performance, and transfer. Even more critical is that students learn how to take on complex challenges by using critical thinking/problem solving skills to solve societal challenges using innovative and transformative new immersive technologies and platforms, such as Metaverse, as research, learning, training, and assessment tools.
“This is exciting work, and the future is full of possibility because simulation and modeling has so many potential applications to help people and our society as a whole,” Azevedo says. “We can’t wait to get started.”
Azevedo also has affiliations with UCF’s departments of computer science and internal medicine. He co-leads UCF’s Learning Sciences cluster, which develops new technologies to improve learning outcomes and human performance, exploring how we interact with and learn using machines. He received his doctorate in educational psychology from McGill University and completed postdoctoral training in cognitive psychology at Carnegie Mellon University. He joined UCF in 2018 and in 2021 he was named among the top 2% of researchers in his field by the journal PLOS Biology.
The award comes during SMST’s 40th anniversary year, which has seen modeling and simulation go from small scale projects to being used in practically every field.
LSU chemists unlock the key to improving biofuel and biomaterial production
IMAGE: PLANT BIOMASS CONSTRUCTED BY CARBOHYDRATE AND AROMATIC COMPONENTS.view more
CREDIT: LSU
As the world searches for and demands more sustainable sources of energy and materials, plant biomass may provide the solution by serving as a renewable resource for biomaterials and biofuel production. However, until now, the complex physical and chemical interactions in plant biomass have been a challenge in post-harvest processing.
In a new study published today in Nature Communications, LSU Department of Chemistry Associate Professor Tuo Wang and his research team reveal how carbohydrates interact with the aromatic polymer, lignin, to form plant biomass. This new information can help advance the development of better technology to use biomass for energy and materials.
The Wang research team examined the nanoscale assembly of lignocellulosic components in multiple plant species, including grasses and hardwood and softwood species. The grasses contain many food crops, such as maize, and are the primary feedstock for biofuel production in the U.S. Woody plants, often used for building construction materials, have become promising candidates for the next generation of biofuel to reduce the dependence on food crops.
The team used their expertise in solid-state nuclear magnetic resonance spectroscopy to compare the nanoscale organization of the lignin-carbohydrate interfaces across the three plant species and reveal how the structures of biopolymers affect their association with other cell wall components.
“We discovered that the hemicellulose xylan uses its flat structure to bind cellulose microfibrils and primarily relies on its non-flat structure to associate with lignin nanodomains,” Wang said. “However, in the tightly packed woody materials, cellulose is also forced to serve as a secondary interactor with lignin.”
The newly discovered, high-resolution information on the organization of the lignin-carbohydrate interfaces has revised the research of plant biomaterials. Through the spectroscopy method, samples being studied were kept in their native status, without chemical perturbation. Results unveiled structural differences underlying the cell wall construction among the different plants.
The research was conducted by a team comprised of LSU graduate students Alex Kirui and Wancheng Zhao as well as postdoctoral researchers Fabien Deligey and Xue Kang from the Wang research group; Frederic Mentink-Vigier, an expert in Dynamic Nuclear Polarization technique at the National High Magnetic Field Laboratory (Tallahassee, Fla.) who collaborated on the project; and Hui Yang at the Pennsylvania State University, who offered extensive modeling expertise.
This methodology enables future opportunities for looking at complex biomolecules in different plants and engineered mutants, which will assist the development of better technology for the production of biorenewable energy and biomaterials.
IMAGE: EXCAVATION OF A NOK VESSEL AT THE IFANA 3 SITE.view more
CREDIT: PETER BREUNIG
FRANKFURT. Over 450 prehistoric pots were examined, 66 of them contained traces of lipids, that is, substances insoluble in water. On behalf of the Nok research team at Goethe University, chemists from the University of Bristol extracted lipid profiles, with the aim of revealing which plants had been used. The results have now been published in “Archaeological and Anthropological Sciences”: over a third of the 66 lipid profiles displayed very distinctive and complex distributions – indicating that different plant species and parts had been processed.
Today, leafy vegetables, for example the cooked leaves of trees such as the baobab (Adansonia digitata) or of the shrubby – nomen est omen – bitter leaf (Vernonia amygdalina), accompany many West African dishes. These leafy sauces are enhanced with spices and vegetables as well as fish or meat, and complement the starchy staples of the main dish, such as pounded yam in the southern part of West Africa or thick porridge made from pearl millet in the drier savannahs in the north. By combining their expertise, archaeology and archaeobotany researchers at Goethe University and chemical scientists from the University of Bristol have corroborated that the origins of such West African dishes date back 3,500 years.
The studies are part of a project funded by the German Research Foundation, which was headed by Professor Peter Breunig and Professor Katharina Neumann and ended in December 2021. For over twelve years, archaeologists and archaeobotanists from Goethe University studied the Nok culture of Central Nigeria, which is known for its large terracotta figures and early iron production in West Africa in the first millennium BC – although the roots of the Nok culture in fact stretch back to the middle of the second millennium. Research focused above all on the social context in which the sculptures were created, that is, including eating habits and economy. Using carbonised plant remains from Central Nigeria, it was possible to prove that the Nok people grew pearl millet. But whether they also used starchy plants, such as yam, and which dishes they prepared from the pearl millet had so far been a mystery.
“Carbonised plant remains such as seeds and nutshells preserved in archaeological sediments reflect only part of what people ate back then,” explains Professor Katharina Neumann. They hoped, she says, that the chemical analyses would deliver additional insights into food preparation. And indeed, with the help of lipid biomarkers and analyses of stable isotopes, the researchers from Bristol were able to show, by examining over 450 prehistoric pots, that the Nok people included different plant species in their diet.
Dr Julie Dunne from the University of Bristol’s Organic Geochemistry Unit says: “These unusual and highly complex plant lipid profiles are the most varied seen (globally) in archaeological pottery to date.” There appear to be at least seven different lipid profiles in the vessels, which clearly indicates the processing of various plant species and plant organs in these vessels, possibly including underground storage organs (tubers) such as yam.
Since the beginning of the project, the archaeobotanists have sought evidence for the early use of yam. After all, the Nok region is situated in the “yam belt” of West Africa, that is, the area of the continent in which yam is nowadays grown. Carbonised remains are of no further help here because the soft flesh of the tubers is often poorly preserved and mostly non-specific as well. The chemical analyses indicate that – apart from leaves and other as yet unidentified vegetables – the Nok people also cooked plant tissue containing suberin. This substance is found in the periderm of both overground and underground plant organs – possibly a first indication that yam was used, if not the unequivocal proof hoped for.
Through the archaeobotanical study of carbonised remains, pearl millet (Cenchrus americanus) and cowpea (Vigna unguiculata), the oily fruits of the African elemi (Canarium schweinfurthii) and a fruit known as African peach (Nauclea latifolia), which due to its high number of seeds is reminiscent of a large fig, were already known. Molecular analysis now rounds off the picture of food preparation at the sites of the Nok culture. Archaeobotanist Dr Alexa Höhn from Goethe University explains: “The visible and invisible remains of food preparation in the archaeological sediment and the pottery give us a much more complete picture of past eating habits. This new evidence suggests a significant time depth in West African cuisine.”
Publication: Julie Dunne, Alexa Höhn, Katharina Neumann, Gabriele Franke, Peter Breunig, Louis Champion, Toby Gillard, Caitlin Walton‑Doyle, Richard P. Evershed Making the invisible visible: tracing the origins of plants in West African cuisine through archaeobotanical and organic residue analysis. Archaeological and Anthropological Scienceshttps://doi.org/10.1007/s12520-021-01476-0
IMAGE: ARCTIC WINTERGREEN, A VERY RARE SPECIES, GROWS AMONG BIRCH AND WILLOW SHRUBS NEAR KANGERLUSSUAQ, GREENLAND.view more
CREDIT: ERIC POST,UC DAVIS
Being common is rather unusual. It’s far more common for a species to be rare, spending its existence in small densities throughout its range. How such rare species persist, particularly in an environment undergoing rapid climate change, inspired a 15-year study in arctic Greenland from the University of California, Davis.
The study, published in the journal Scientific Reports, found that caribou and muskoxen helped mitigate the effects of climate change on rare arctic plants, lichens and mushrooms at the study site.
The authors suggest that by constraining the abundance of the two most common plant species — dwarf birch and gray willow — large herbivores may allow other, less common species to persist rather than be shaded or outcompeted for nutrients by the woody shrub’s canopy, or suppressed by leaf litter and cooler soils.
“This is more evidence that conserving large herbivores is really important to maintaining the compositional integrity of species-poor systems like the arctic tundra,” said lead author Eric Post, director of the UC Davis Polar Forum and a professor in the UC Davis Department of Wildlife, Fish and Conservation Biology.
A rare find
Recent studies have shown that when rare species risk extinction due to climate change, it is often due to effects on local habitat. Greater numbers of rare species persist in regions with a stable climate than in regions with a changing climate. This study shows that species interactions can also be important in maintaining rare species under climate change.
For this study, the scientists investigated the effects of warming and the presence or exclusion of large herbivores — caribou and muskoxen — on 14 species of tundra plants, lichens and mushrooms, three of which were common and 11 of which were rare in the study site, looking for trends in commonness or rarity.
They found no predictable pattern related to warming. It made some plants more common and others rarer.
But the presence or absence of caribou and muskoxen made a clear difference. Excluding large herbivores from study plots made seven species — five of them rare — less common, and two species more common, and led to common species dominating study plots.
A herd of caribou in arctic Greenland. Caribou at this study site have been declining over the past several years, while muskoxen have been increasing. Such herbivores help rare plant species persist in a rapidly changing climate.
CREDIT
Eric Post, UC Davis
Herbivores’ critical role in sustaining biodiversity
Caribou at the study site near Kangerlussuaq, Greenland, dropped from several hundred animals in the early 2000s, at the beginning of this study, to a little over 100 by the study’s end. Muskoxen increased from about 20 to 50 over the same period, according to a March 2021 study Post co-authored. Meanwhile, the arctic tundra is warming two to three times as fast as the rest of the planet.
“The conservation of large herbivores will serve a critical role in preserving arctic tundra as it warms,” Post said. “If caribou or muskoxen eventually go locally extinct from parts of the Arctic, or even fall to severely low abundance, what we’ll likely see in response to warming is a tundra increasingly dominated by a few common species, like shrubs.”
Post said that rare species contribute vitally to biodiversity, ecosystem function and resilience, largely because there are so many of them compared to common species.
“Creative solutions to sustaining tundra biodiversity, such as maintaining intact populations of large herbivores, will help buffer this sensitive biome against climate change,” Post said.
This study’s co-authors include Christian Pedersen of the Norwegian Institute of Bioeconomy Research, and David A. Watts of Alaska Department of Health and Social Services.
The study was funded by the National Science Foundation, National Geographic Committee for Research and Exploration, and Penn State University.
A muskox stands amid Greenland's arctic tundra. Large herbivores have been found to play a critical role in maintaining tundra biodiversity.
