Tuesday, September 05, 2023

Youth-centered groups, classes may be key in maintaining faith as kids age


Parents have largest influence on children’s religious beliefs, but congregations play integral role

Peer-Reviewed Publication

UNIVERSITY OF GEORG 

FAITH IS IDEOLOGY 
THAT'S WHY THERE WERE SOCIALIST SUMMER CAMPS


Parents are an undeniably influential force in their children’s lives. But a new study from the University of Georgia suggests that when it comes to religion, an engaged congregation may also be a deciding factor of whether youth stay involved in their religious practice as they age.

The study found that the way parents live and the conversations they have with their children have the largest impact on whether their kids continue in their faith as they age.

But things like youth groups, Sunday school and attending weekly services make a big difference in youths’ feelings of belonging within their religious community, according to the research. As a result of that, they may be more likely to stay in their faith as they grow.

About three out of 10 Americans currently identify as non-religious, according to the Pew Research Center. And that number is expected to rise.

For parents who are invested in religious tradition and religious community leaders, that may be concerning.

“It used to be just a truism that people stop attending religious services in college and then they came back when they had kids,” said Bill Stanford, lead author of the study and a doctoral graduate of UGA’s College of Family and Consumer Sciences. “But more recent studies have pointed out people aren't coming back after they have kids. The million-dollar question is why.”

1 in 6 kids from religious families say they never discuss religion with parents

The researchers analyzed responses from more than 1,700 youth and their caregivers interviewed over several years as part of the National Study of Youth and Religion. The dataset provides a big picture view of young people’s relationship with religion and spirituality and includes individuals from a variety of faiths, such as Christianity, Islam and Judaism, among others.

More than three out of four of the parents in the study said their faith was either a very or extremely important guide in their daily decisions. And more than half said they went to at least weekly religious services.

But more than one in six of the kids surveyed said they never discussed religion with their parents. Less than half of the youth reported having conversations about religion with their caregivers on a weekly basis.

“It's not something that we commonly talk about, in terms of educating parents on how to help facilitate religiosity and spirituality with their kids,” said Ted Futris, co-author of the study and a professor of human development and family science. “It's often seen as something personal.

“What Bill’s work is showing is that building spirituality in youth is a community process. It’s both parents and the faith-based community working together to help foster that religiosity and spirituality among our young people.”

Only 2 out of 5 youth attend youth group

Although more than 60% of adults said youth ministry was a priority in their faith communities, only two out of five children said they participated in a youth-oriented group.

Almost 30% of youth reported never taking religious education courses, and half said they’d never undergone a rite of initiation into the religious community, such as a baptism or confirmation.

“The role of parents is incredibly powerful in shaping future religiosity in children, but engagement matters,” said Stanford, who is now an associate priest at St. Thomas Anglican Church in Athens, Georgia. “Nonfamilial adult mentorship relationships are extremely important. Integrating youth into the community and connecting them with religious education and the rites of passage—the congregation has an important role to play in helping pass down religious tradition.”

Youth groups, religious education courses lead to more religiosity in young people

Young people in religious organizations that emphasize youth group and religious education and expect kids to regularly attend worship services are more likely to report high levels of personal religious practice, such as fasting and independent study of religious texts.

The study also explored differences between religious denominations. The researchers found some traditions put more of an emphasis on integrating youth into their communities than others.

“What you're doing as parents is you're creating a framework through which to view the world,” Stanford said. “And religion's part of that for a lot of people. Religion becomes part of the scaffolding for how you view the world.

“I would say part of purposefully engaging youth is thinking through, how are we as a congregation coming alongside parents and providing a lens through which the world makes sense? How are we being purposeful about talking through what we believe, why we believe it, how we see it acting in the world?”

Published in Applied Developmental Science, the study was co-authored with Geoffrey Brown, of UGA’s College of Family and Consumer Sciences, and J. Derrick Lemons, of UGA’s Franklin College of Arts and Sciences

 

AI performs comparably to human readers of mammograms


Peer-Reviewed Publication

RADIOLOGICAL SOCIETY OF NORTH AMERICA

Mammogram shows an 8-mm ill-defined mass 

IMAGE: (A) RIGHT MEDIOLATERAL OBLIQUE UNADULTERATED MAMMOGRAM SHOWS AN 8-MM ILL-DEFINED MASS (ARROWHEAD), WHICH, AFTER BIOPSY, WAS DETERMINED TO BE A HISTOLOGIC GRADE 2 DUCTAL CARCINOMA OF NO SPECIAL TYPE. (B) MAMMOGRAM SHOWS FINDINGS BY HUMAN READERS (BLUE AREAS) AND THE LUNIT INSIGHT MMG ARTIFICIAL INTELLIGENCE (AI) ALGORITHM (RED CROSS). EACH BLUE DOT IS A MARK PLACED BY AN INDIVIDUAL HUMAN READER ON A PERCEIVED ABNORMALITY WHEN THE PERSONAL PERFORMANCE IN MAMMOGRAPHIC SCREENING (PERFORMS) CASE WAS READ. A REGION OF INTEREST (PENTAGON) HAS BEEN ANNOTATED BY THE PERFORMS SCHEME ORGANIZERS AND THEIR EXPERT RADIOLOGY PANEL. AI HAS CORRECTLY MARKED THE REGION OF INTEREST IN THE RIGHT BREAST FOR RECALL. SOURCE: PERFORMS VIA YAN CHEN. view more 

CREDIT: RADIOLOGICAL SOCIETY OF NORTH AMERICA




OAK BROOK, Ill. – Using a standardized assessment, researchers in the UK compared the performance of a commercially available artificial intelligence (AI) algorithm with human readers of screening mammograms. Results of their findings were published in Radiology, a journal of the Radiological Society of North America (RSNA).

Mammographic screening does not detect every breast cancer. False-positive interpretations can result in women without cancer undergoing unnecessary imaging and biopsy. To improve the sensitivity and specificity of screening mammography, one solution is to have two readers interpret every mammogram.

According to the researchers, double reading increases cancer detection rates by 6 to 15% and keeps recall rates low. However, this strategy is labor-intensive and difficult to achieve during reader shortages.

“There is a lot of pressure to deploy AI quickly to solve these problems, but we need to get it right to protect women’s health,” said Yan Chen, Ph.D., professor of digital screening at the University of Nottingham, United Kingdom.

Prof. Chen and her research team used test sets from the Personal Performance in Mammographic Screening, or PERFORMS, quality assurance assessment utilized by the UK’s National Health Service Breast Screening Program (NHSBSP), to compare the performance of human readers with AI. A single PERFORMS test consists of 60 challenging exams from the NHSBSP with abnormal, benign and normal findings. For each test mammogram, the reader’s score is compared to the ground truth of the AI results.

“It’s really important that human readers working in breast cancer screening demonstrate satisfactory performance,” she said. “The same will be true for AI once it enters clinical practice.”

The research team used data from two consecutive PERFORMS test sets, or 120 screening mammograms, and the same two sets to evaluate the performance of the AI algorithm. The researchers compared the AI test scores with the scores of the 552 human readers, including 315 (57%) board-certified radiologists and 237 non-radiologist readers consisting of 206 radiographers and 31 breast clinicians.

“The 552 readers in our study represent 68% of readers in the NHSBSP, so this provides a robust performance comparison between human readers and AI,” Prof. Chen said.

Treating each breast separately, there were 161/240 (67%) normal breasts, 70/240 (29%) breasts with malignancies, and 9/240 (4%) benign breasts. Masses were the most common malignant mammographic feature (45/70 or 64.3%), followed by calcifications (9/70 or 12.9%), asymmetries (8/70 or 11.4%), and architectural distortions (8/70 or 11.4%). The mean size of malignant lesions was 15.5 mm.

No difference in performance was observed between AI and human readers in the detection of breast cancer in 120 exams. Human reader performance demonstrated mean 90% sensitivity and 76% specificity. AI was comparable in sensitivity (91%) and specificity (77%) compared to human readers.

“The results of this study provide strong supporting evidence that AI for breast cancer screening can perform as well as human readers,” Prof. Chen said.

Prof. Chen said more research is needed before AI can be used as a second reader in clinical practice.

“I think it is too early to say precisely how we will ultimately use AI in breast screening,” she said. “The large prospective clinical trials that are ongoing will tell us more. But no matter how we use AI, the ability to provide ongoing performance monitoring will be crucial to its success.”

Prof. Chen said it’s important to recognize that AI performance can drift over time, and algorithms can be affected by changes in the operating environment.

“It’s vital that imaging centers have a process in place to provide ongoing monitoring of AI once it becomes part of clinical practice,” she said. “There are no other studies to date that have compared such a large number of human reader performance in routine quality assurance test sets to AI, so this study may provide a model for assessing AI performance in a real-world setting.”


  

Left mediolateral oblique mammogram. Unadulterated mammogram shows an asymmetric density (arrowhead) which, after biopsy, was determined to be a histologic grade 2 ductal carcinoma. (B) Artificial intelligence (AI) has correctly marked the region of interest in the left breast for recall (red cross) when set at a recall threshold of 2.91 or higher to match average human specificity, demonstrating a true-positive case. (C) AI has not marked the region of interest in the same breast when set at a recall threshold of 3.06 or higher, indicating a false-negative case. Blue dots indicate findings identified by the human readers. This shows how modifying the threshold for recall can impact the sensitivity of the AI model. Source: Personal Performance in Mammographic Screening via Yan Chen.

CREDIT

Radiological Society of North America

“Performance of a Breast Cancer Detection AI Algorithm Using the Personal Performance in Mammographic Screening Scheme.” Collaborating with Dr. Chen were Adnan G. Taib, B.M.B.S., Iain T. Darker, Ph.D., and Jonathan J. James, FRCR.

In 2023, Radiology is celebrating its 100th anniversary with 12 centennial issues, highlighting Radiology’s legacy of publishing exceptional and practical science to improve patient care.

Radiology is edited by Linda Moy, M.D., New York University, New York, N.Y., and owned and published by the Radiological Society of North America, Inc. (https://pubs.rsna.org/journal/radiology)

RSNA is an association of radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Illinois. (RSNA.org)

For patient-friendly information on breast cancer screening, visit RadiologyInfo.org.

 

Obesity experts spotlight safety gap in clinical trials and drug labeling for people with obesity


A new publication calls for safe and effective drug dosing and better labeling


Peer-Reviewed Publication

EMERALD LAKE SAFETY




A new opinion piece published in Health Affairs Forefront raises questions around current approaches to assess drug safety and effectiveness in people with obesity. The article sheds light on how increased body fat can modify the effects of drugs used to treat common conditions, in some cases rendering the drugs ineffective or unsafe for people with obesity.

The article, titled “Assessments Of Drug Safety And Effectiveness Continue To Fail People With Obesity,” argues that drug manufacturers should be required to show correct dosing instructions on their labels for people with obesity when they are well-known and, when appropriate, include people with obesity in clinical trials during the drug approval process.

“People with obesity deserve to know that the prescription drugs they take are safe and effective for them,” according to William Dietz, Director of the STOP Obesity Alliance at The George Washington University, and one of the paper’s authors. “Today, neither patients nor their providers know how some drugs may act differently in people with obesity.”

According to the article, the FDA has recognized that people with obesity are often intentionally excluded from clinical trials in an effort to reduce the observed variability of early-phase trials. For some drugs, this makes little or no clinical difference. But with drugs that are lipophilic, meaning highly fat soluble, the difference in clinical impact for patients with obesity can be serious or even fatal.

For example, brexpiprazole, marketed under the brand name Rexulti, is a drug that treats schizophrenia and depression, two very serious conditions with life-threatening implications. Rexulti is lipophilic. It was approved by the FDA in 2015 without being tested fully on people with obesity, despite the fact that around 60% of people with schizophrenia have obesity. A 2021 study conducted by former senior FDA officials, as well as researchers at Tufts and Emerald Lake Safety, showed that Rexulti took substantially longer to reach effective levels in people with obesity –and in some patients may never reach effective levels. Yet the label provides no specific instructions or warning for patients or their providers regarding how to treat people with obesity.

This lack of information may have serious consequences. For example, people with schizophrenia who are under-treated or who stop treatment may suffer mental health crises or harm themselves or others.

As another example, posaconazole, marketed under the brand name Noxafil, is a drug that treats fungal infections such as candidiasis, which is reported to be more frequent in people with obesity. Researchers at Tufts and Emerald Lake Safety showed that the half-life of posaconazole is significantly longer in people with obesity. This results in prolonged inhibition of a key drug metabolizing enzyme and puts people with obesity at risk of dangerous drug-drug interactions for weeks after they stop taking posaconazole. There is no information on the Noxafil label to address these findings, despite its known risks.

“These data are part of the growing body of literature demonstrating that obesity can change the pharmacokinetics of some drugs, including changes in metabolism, clearance, volume of distribution, and half-life,” stated Christina Chow, Head of Research at Emerald Lake Safety and co-author. “Studies must be done in people with obesity to assess the drugs’ clinical impact before they are on the market, and labels must reflect this information. Unfortunately, the effects of obesity on the pharmacokinetics of many commonly prescribed drugs are still unknown.”

The authors recommend a three-pronged approach to address the gap:

  • First, the FDA should revise its Clinical Trials Guidance Documents and Regulations Relating to Good Clinical Practice to require testing on people with obesity.
  • Second, whenever appropriate, drug manufacturers should include information on the effects of obesity on specific drugs in the drug package insert.
  • Third, a reporting system for adverse events relating to drug metabolism in people with obesity should be established to enable the FDA and drug manufacturers to identify and track issues.

“Regulators and policy makers can and should act now to address this gap, reduce risks to patients with obesity, and improve health,” says co-author David J. Greenblatt, Louis Lasagna Endowed Professor of Immunology at Tufts University.

STOP Obesity Alliance comprises a diverse group of business, consumer, government, advocacy, and health organizations dedicated to reversing the obesity epidemic in the United States. Emerald Lake Safety conducts independent research to make pharmaceuticals safer.

 

Link to article: https://www.healthaffairs.org/content/forefront/assessments-drug-safety-and-effectiveness-continue-fail-people-obesity

DOI: 10.1377/forefront.20230829.36462

 

Media Contacts:

Kelly Whittier, kwhittier@gwu.edu, 202-604-9893

Rachel Larris, rlarris@gwu.edu

 

New research sheds light on origins of social behaviors


Peer-Reviewed Publication

CORNELL UNIVERSITY




ITHACA, N.Y. – Male fruit flies don’t usually like each other. Socially, they reject their fellow males and zero in on the females they discern via chemical receptors – or so scientists thought.

New research from Cornell University biologists suggests the fruit fly’s visual system, not just chemical receptors, are deeply involved with their social behaviors. The work sheds light on the possible origin of differences in human social behaviors, such as those seen in people with bipolar disorder and autism.

The paper, “Visual Feedback Neurons Fine-tune Drosophila Male Courtship via GABA-mediated Inhibition,” published in Current Biology on Sept. 5.

Many species of animals use vision to regulate their social behaviors, but the underlying mechanisms are largely unknown. In fruit flies, vision is thought to be used explicitly for motion detection and following, not to regulate social behaviors – but the researchers found that may not be the case.

“In our study, we found that hyperactivating the visual system overran the inhibition generated by chemical signals emitted by the male fly to say to the other male, ‘Okay, you know, I’m another male, don’t mess with me,’” said senior author Nilay Yapici, assistant professor of neurobiology and behavior. “Surprisingly, increasing the visual gain in the brain somehow overrides the chemosensory inhibition, attracting male flies to other males.”

The researchers found that altering the GABARAP/GABAA receptor signaling in visual feedback neurons in the male brain affected the flies’ social inhibitions. When GABARAP is knocked down in the visual system, the males unexpectedly exhibit increased courtship toward other males.

The researchers have found that genes similar to those in the human brain control the fruit fly’s visual neurons. Decreasing GABA signaling in the human brain has been associated with social withdrawal characteristics in conditions such as autism and schizophrenia.

“Our results offer a promising avenue for investigating how these proteins regulate social behaviors in the mammalian brain and their potential contribution to human psychiatric conditions,” said lead author Yuta Mabuchi, Ph.D. ’23.

For additional information, see this Cornell Chronicle story.

-30-

 

Hungarian researchers reveal the complex society of wild horses by drones


The results show that wild horses, just like humans, live in a complex, multilevel society, the structure of which ‒ and even group changes in the past and future ‒ can be understood with the help of high-resolution aerial videos


Peer-Reviewed Publication

EÖTVÖS LORÁND UNIVERSITY

Harem stallions 

IMAGE: HAREM STALLIONS FIGHT FOR THE FEMALES AND PROTECT THEIR HAREMS AGAINST PREDATORS AND THE BACHELOR MALES, WHICH ARE NON-BREEDING MALES WITHOUT A HAREM. view more 

CREDIT: PHOTO: KATALIN OZOGÁNY




Researchers of the Hungarian Research Network (HUN-REN), the University of Debrecen (UD), the Eötvös Loránd University (ELTE) and the Hortobágy National Park Directorate investigated the social system of the Przewalski’s horse herd in Hortobágy by combining drone-based movement analysis and long-term population monitoring data. The researchers used two drones to track the movements of each individual in the herd of 278 Przewalski’s horses with high temporal and spatial resolution, while individually identifying most of the animals. The results show that wild horses, just like humans, live in a complex, multilevel society, the structure of which ‒ and even group changes in the past and future ‒ can be understood with the help of high-resolution aerial videos. The paper presenting the research was published in the prestigious scientific journal Nature Communications.

Investigating the social behaviour of a large group of animals is a time-consuming work if one uses classical observation methods. However, the study published in Nature Communications highlights that by collecting high-resolution data, even a few minutes of footage of animal movements can provide enough information to learn about the social structure of the population and even draw conclusions about the past and future dynamics of the group.

"We wanted to investigate the group movements of the Przewalski’s horse herd in Hortobágy, Hungary. However, observing nearly 300 horses at the same time is not an easy task," says Katalin Ozogány, the first author of the study, member of the HUN-REN–UD Behavioural Ecology Research Group of the Hungarian Research Network and the University of Debrecen (Hungary). "We took aerial videos of the herd using drones while they were moving around the reserve, and based on the footage, we determined the movement routes of all the individuals of the herd with high spatio-temporal resolution."

Multilevel societies

The multilevel social structure that is also characteristic of humans is rare in animals. It is mainly found in primates, but also occurs in cetaceans, elephants, and some ungulates that individuals form smaller family groups (for example harems or a group of related females led by a matriarch), and these family groups form a larger, looser community.

VIDEOABSTRACT: youtube.com/watch?v=H2BhFjEbZDE

Przewalski’s horses have been living in Hortobágy since 1997 in the Pentezug reserve. In the first years after founding the population, the harems of wild horses lived in their own home ranges and rarely interacted with each other. For over a decade, however, the harems together form a large herd, in which harems can still be distinguished, but they move together in the reserve. The researchers studied the group movements of this complex herd, made up of harems.

Analysis of collective movements reveals social behaviour

Analysis of the herd’s movements yielded surprising results. "The individuals of the group coordinate their movements and align with each other, and by detecting these fine interactions between the individuals, it turned out that we can assess the herd's social network based on the group movements," explains lead author Máté Nagy, head of the Collective Behaviour 'Lendület' Research Group of the Hungarian Academy of Sciences and Eötvös Loránd University (Hungary).

The researchers combined the short-term movement observations of a few minutes with the long-term population monitoring data of the national park going back two decades. Since the establishment of the reserve, the wild horses have been individually recognized by the park staff who regularly collected data on population changes. "Thanks to population monitoring, we know the parentage of the animals, which we also confirm with genetic sampling, as well as their place in the social system, that is, we regularly record which individual belongs to which harem," says co-author Viola Kerekes, project leader of the Hortobágy National Park Directorate.

The herd's social network

The analyses showed that the social relations of wild horses are related to kinship and familiarity of the animals. For example, female horses (mares) are closer to each other in the social network if they have been harem mates for a longer time. Kinship may play a significant role in the organization of harems into herds since harems of sibling stallions (the single breeding male in a harem) are closer to each other in the social network than harems of unrelated stallions. Between the closer harems, at the same time, the dispersal of mares was greater, which also contributes to the relations between harems through familiarity.

"It is an exceptional opportunity to explore the social network of an entire population and its dynamics," explains co-author Attila Fülöp, a researcher at the Babeş-Bolyai University (Romania) and the HUN-REN–UD Behavioural Ecology Research Group. It turned out that older and larger harems, which typically belong to older and more experienced stallions, occupy more central locations in the herd’s social network. A possible explanation is that harem stallions form an alliance to protect their harems more effectively against the bachelor males.

Future group dynamics

"One of the surprising outcomes of the study is that we can infer future group dynamics by observing current movement," adds Zoltán Barta, lead author, head of the Department of Evolutionary Zoology of the University of Debrecen and the HUN-REN–UD Behavioural Ecology Research Group. The researchers showed that mares that lived in different harems at the time of the aerial observations but became harem mates within two years after the observations, were already moving in more similar routes than the other mares. So, through the movement analysis, it was also possible to conclude which mares will leave their harem in the next two years and which harem they will transfer to.

"Not only did we learn new, previously unknown details about the social life of Przewalski's horses, but we highlighted that drone observations, which can be applied even in wild populations, can provide very detailed information."


In Hortobágy National Park, Hungary, harems of Przewalski’s horses come together to form a large multilevel herd. Each harem consists of a single male - the harem stallion -, several females and their juvenile offspring.

CREDIT


Authors Katalin Ozogány, Attila Fülöp and Zoltán Barta are researchers at the University of Debrecen and members of the HUN-REN–UD Behavioural Ecology Research Group. Attila Fülöp is also a researcher at the Babeş-Bolyai University. Viola Kerekes works at the Hortobágy National Park Directorate. Máté Nagy is associated with Eötvös Loránd University, the Hungarian Academy of Sciences, and the Max Planck Institute of Animal Behavior.

 

Extreme El Niño weather saw South America’s forest carbon sink switch off


Peer-Reviewed Publication

UNIVERSITY OF LEEDS

Forest at Chapada de Guimaraes, Brasil 

IMAGE: THE VALLEY FOREST AT CHAPADA DE GUIMARAES, BRASIL, IS ON THE PERIPHERY OF THE AMAZON FOREST AND IS ESPECIALLY VULNERABLE TO DROUGHT. view more 

CREDIT: RAINFOR.ORG




Extreme El Niño weather saw South America’s forest carbon sink switch off

  • Hot and dry conditions resulted in increased tree death 
  • Evidence that most forest areas withstand periods of severe drought
  • Greatest impact in forests with drier climates 

Tropical forests in South America lose their ability to absorb carbon from the atmosphere when conditions become exceptionally hot and dry, according to new research. 

 

For a long time, tropical forests have acted as a carbon sink, taking more carbon out of the air than they release into it, a process that has moderated the impact of climate change. 

 

But research led by Dr Amy Bennett, a Research Fellow at the University of Leeds, found that in 2015 – 2016, when an El Niño climate event resulted in drought and the hottest temperatures ever recorded, South American forests were unable to function as a carbon sink. 

 

El Niño occurs when sea-surface temperatures in the Pacific Ocean increase sharply, triggering a major shift in the world’s climate system. In 2015-2016, the result was exceptionally hot weather for South America. A similar event is underway now. 

 

Dr Bennett, from the School of Geography at Leeds, said: “Tropical forests in the Amazon have played a key role in slowing the build-up of carbon dioxide in the atmosphere. 

 

“Scientists have known that the trees in the Amazon are sensitive to changes in temperature and water availability, but we do not know how individual forests could be changed by future climate change. 

 

“Investigating what happened in the Amazon during this huge El Niño event gave us a window into the future by showing how unprecedented hot and dry weather impacts forests.” 

 

The researchers today report their findings in the journal Nature Climate Change. The study united the RAINFOR and PPBio research networks, with dozens of short-term grants enabling more than 100 scientists to measure forests for decades across 123 experimental plots. 

 

The plots span Amazon and Atlantic forests as well as drier forests in tropical South America. 

 

These direct, tree-by-tree records showed that most forests had acted as a carbon sink for most of the last 30 years, with tree growth exceeding mortality. When the 2015–2016 El Niño hit, the sink shut down. This was because tree death increased with the heat and drought.  

 

Professor Beatriz Marimon, of Brazil’s Mato Grosso State University, added “Here in the southeastern Amazon on the edge of the rainforest, the trees may have now switched from storing carbon to emitting it. While tree growth rates resisted the higher temperatures, tree mortality jumped when this climate extreme hit.” 

 

Study’s findings 

Of the 123 plots studied, 119 of them experienced an average monthly temperature increase of 0.5 degrees Celsius. 99 of the plots also suffered water deficits. Where it was hotter, it was also drier. 

 

Prior to El Niño, the researchers calculated that the plots were storing and sequestering around one third of a tonne of carbon per hectare per year. This declined to zero with the hotter and drier El Niño conditions. 

 

The change was due to biomass being lost through the death of trees. 

 

Writing in the paper, the researchers noted that the greatest relative impact of the El Niño event were in forests where the long-term climate was already relatively dry. 

 

The expectation was that wetter forests would be most vulnerable to the extreme drier weather, as they would be least adapted to such conditions. However, the opposite was the case. Instead, those forests more used to a drier climate at the dry periphery of the tropical forest biome turned out to be most vulnerable to drought. 

 

This suggested some trees were already operating at the limits of tolerable conditions. 

 

For Professor Oliver Phillips, an ecologist at the University of Leeds who supervised the research and leads the global ForestPlots initiative, the findings offered hope about the resilience of the South American tropical nature. 

 

He added: “The full 30-year perspective that our diverse team provides shows that this El Niño had no worse effect on intact forests than earlier droughts. Yet this was the hottest drought ever. 

 

“Where tree mortality increased was in the drier areas on the Amazon periphery where forests were already fragmented. Knowing these risks, conservationists and resource managers can take steps to protect them. 

 

“Through the complex dynamics that happen in forest environments, land clearance makes the environment drier and hotter, further stressing the remaining trees. 

 

“So, the big challenge is to keep forests standing in the first place. If we can do that, then our on-the-ground evidence shows they can continue to help lock up carbon and slow climate change.” 

 

Two reports are published in Nature Climate Change related to this research. The scientific paper, “Sensitivity of South American tropical forests to an extreme climate anomaly”, and a research brief titled “Impact of the 2015-2016 El Nino on South American tropical forests”. 

 

Once the paper is live, it can be downloaded from the journal website: https://www.nature.com/articles/s41558-023-01776-4