As galaxies move through the Universe, they sometimes encounter other galaxies. As they interact, each galaxy’s gravity pulls on the other. The ensuing tug-of-war flings gas and stars away from the galaxies, leaving behind streams of material known as tidal tails.

And that’s just what scientists believe happened to SDSS J1448+1010, but with a plot twist. The massive galaxy, which was born when the Universe was about half its current age, has nearly completed merging with another galaxy. During observations with the HST and ALMA — an international collaboration in which the U.S. National Science Foundation’s National Radio Astronomy Observatory (NRAO) is a partner — scientists discovered tidal tails containing roughly half of the entire system’s cold, star-forming gas. The discovery of the forcefully discarded material — equal to 10 billion times the mass of Earth’s Sun — was an indication that the merger may be responsible for snuffing out star formation, and that’s something scientists didn’t expect.

“What initially made this massive galaxy interesting was that, for some reason, it suddenly stopped forming stars about 70 million years ago immediately following a burst of star-forming activity. Most galaxies are happy to just keep forming stars,” said Justin Spilker, an astronomer at Texas A&M University and the lead author of the paper. “Our observations with ALMA and Hubble proved that the real reason the galaxy stopped forming stars is that the merger process ejected about half the gas fuel for star formation into intergalactic space. With no fuel, the galaxy couldn’t keep forming stars.”

The discovery is shedding light on the processes by which galaxies live or die, and helping scientists to better understand their evolution.

“When we look out at the Universe, we see some galaxies that are actively forming new stars, like our own Milky Way, and some that aren’t. But those ‘dead’ galaxies have many old stars in them, so they must have formed all of those stars at some point and then stopped making new ones,” said Wren Suess, a cosmology fellow at the University of California Santa Cruz and a co-author of the paper. “We still don’t yet understand all of the processes that make galaxies stop forming stars, but this discovery shows just how powerful these major galaxy mergers are, and how much they can affect how a galaxy grows and changes over time.”

Because the new result is from a single observation, it is currently unclear just how common this tug-of-war and its resultant quiescence may be. However, the discovery challenges long-held theories about exactly how star formation stops and galaxies die and has provided scientists with an exciting new challenge: to find more examples.

“While it’s pretty clear from this system that cold gas really can end up way outside of a merger system that shuts off a galaxy, the sample size of one galaxy tells us very little about how common this process is,” said David Setton, a graduate student in the department of physics and astronomy at the University of Pittsburgh and a co-author of the paper. “But, there are many galaxies out there like J1448+1010 that we’re able to catch right in the middle of those crashes and study exactly what happens to them when they go through that stage. The ejection of cold gas is an exciting new piece of the quiescence puzzle, and we’re excited to try to find more examples of this.”

Spilker added, “Astronomers used to think that the only way to make galaxies stop forming stars was through really violent, fast processes, like a bunch of supernovae exploding in the galaxy to blow most of the gas out of the galaxy and heat up the rest. Our new observations show that it doesn’t take a ‘flashy’ process to cut off star formation. The much slower merging process can also put an end to star formation and galaxies.”

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The heavy elements in interstellar matter significantly impact the mechanism of star formation. In the early universe, the abundance of heavy elements was lower than in the present universe because there was not enough time for nucleosynthesis to produce heavy elements in stars. It has not been well understood how star formation in such an environment differs from present-day star formation.

An international team led by Professor Toshikazu Onishi, Osaka Metropolitan University, and Project Assistant Professor Kazuki Tokuda, Kyushu University/NAOJ, used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe high-mass young stellar objects in the Small Magellanic Cloud.

The Small Magellanic Cloud is characterized by a low abundance of elements heavier than helium, similar to the galaxies 10 billion years ago. The target provides a detailed observational view thanks to the relatively close distance from Earth. In this study, researchers detected a bipolar gas stream flowing out of the “baby star” Y246 and determined that the molecular flow has a velocity of more than 54,000 km/h in both directions.

In the present universe, growing “baby stars” are thought to have their rotational motion suppressed by this molecular outflow during gravitational contraction, accelerating the star growth. The discovery of the same phenomenon in the Small Magellanic Cloud suggests that this process of star formation has been common throughout the past 10 billion years. The team also expects this discovery to bring new perspectives to studying stars and planet formation.

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PNe are the ejected, glowing shrouds of dying stars that shine with a rich emission line spectrum and display, as a result, their distinct colours and shapes that make them photogenic magnets for public interest. It was no coincidence that one of the first James Webb Space Telescope (the largest optical telescope in space) images released to the public was a PN.

The PN, with the rather ungainly name of “IPHASX J055226.2+323724,” is only the third example of an association between a PN and an OC out of the ~4,000 PNe known in our Galaxy. It also appears to be the oldest PN ever found. The small team led by Professor Quentin PARKER, Director of the HKU LSR, have determined some interesting properties for their discovery: the authors found the PN has a “kinematic age” of 70,000 years. This estimate is based on how fast the nebula is expanding, as determined from the PN emission lines, and assuming this speed has remained effectively the same since the beginning, and is the time elapsed since the nebular shell was first ejected by the host, a dying star. This compares to typical PN ages of 5,000-25,000 years. It is truly a grand old dame in PN terms but of course a mere “blink of the eye” in terms of the life of the original star itself that runs to hundreds of millions of years.

Because this “grand old dame” lives in a stellar cluster, this environment enables the team to determine powerful additional parameters not possible for the general Galactic PN population. These include estimating the mass of the PN’s progenitor star when it turned off the stellar main sequence, as derived from the observed properties of the thousands of stars in the cluster when plotted in a so-called colour-magnitude diagram. The team can also estimate the residual mass of the central star that ejected the PNe via theoretical isochrones and observed properties of the hot, blue central star. As a result, they figured how massive the star was that ejected the PN gaseous shell when it was born and how much mass is now left in its residual, contracting hot core (which is already a so-called ‘White Dwarf’ star). Fresh “Gaia” data for the hot blue, PN central star also provide a good distance estimate allowing the PN’s actual size at this extreme age to be determined as 3.2pc (parsec, an astronomical unit of measure for interstellar space with 1pc equals to 3.26 light-years) in diameter — unsurprisingly perhaps also at the extreme end of known PN physical sizes.

Former HKU PhD student Dr Vasiliki FRAGKOU, the first author of the study stated, “I am so excited to be able to work on these fascinating rare cases of OC-PN associations because they keep turning up important science results, like all three cases we have found are butterfly (bi-polar) PN in terms of shape, all are very faint and highly evolved, and all have Type-I chemistry according to their emission lines, and of course all have intermediate to high progenitor masses.”

Corresponding author Professor Quentin Parker said, “This is only the third example of a PN found in a Galactic open star cluster, and my group has found all three confirmed examples. They are incredibly rare but also very important as these beautiful objects allow us to independently determine points on the so called initial to final mass relation (IFMR) for stars — an important astrophysical relation — independent of the traditional method of using white dwarfs in clusters. Intriguingly, all our points lie just below the empirical IFMR trend currently established but add to the “kink” in this relation found recently in the 2-3 Solar mass range for the original progenitor mass by Marigo et al in the Nature Astronomy journal. Our OC-PN points fortuitously are found in currently sparsely populated regions of the IFMR, making them even more valuable.”

Co-author Professor Albert ZILJSTRA, Hung Hing Ying Distinguished Visiting Professor in Science and Technology at HKU LSR from the University of Manchester commented on the PN visibility lifetimes which have previously been much shorter in the general Galaxy. “This new result implies that the location of a PN in an OC provides an environment suitable for allowing the PNe to expand and fade without disruption by the ambient ISM (which is typically much weaker in an OC) and not as would be the case in the Galaxy.”

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“We concluded that many of the symptoms children experience post-COVID-19 are similar to what is seen in adults, but there are some features more unique to children, such as myocarditis, abnormal liver enzymes, hair loss, skin rashes and diarrhea,” said Rao. “There has been a critical need to understand the impact of COVID-19 in children both in the short as well as long-term. This is one of biggest studies we know of to explore what the post-acute sequelae look like in kids. Studies using electronic health record data are a great way to explore research questions that require further confirmation in longer term prospective studies.”

While the presentation has some overlap compared with adults, distinct features exist in children. The risk for PASC appears to be higher in children younger than five years of age, those with medical complexity and those admitted to the intensive care unit with their initial COVID-19 infection.

The exploratory study, “Syndromic, Systemic and Medication Features of Post-acute Sequelae of SARS-CoV-2 Infection in Children and Adolescents: EHR-based Cohort Study from the RECOVER Program,” used electronic health record data from PEDSnet member institutions of 659,286 children tested for SARS-CoV-2 and compared 59,893 children who tested positive with those who tested negative.

The NIH RECOVER Pediatric EHR Cohort investigators conducted a multistate analysis using EHR data of children and people younger than 21 years of age who underwent testing for SARS-CoV-2 at one of eight pediatric health systems in the country between March 1, 2020, and Oct. 31, 2021. Clinicians identified conditions, symptoms and medications associated with PASC in the one to six months following testing. Out of 660,000 children who underwent testing, 9% were positive and most were tested as outpatients.

Symptoms most strongly associated with infection included changes in loss of smell and taste, hair loss, chest pain, abnormal liver enzymes, skin rashes, fever and chills, fatigue and malaise. Conditions most strongly associated with infection included myocarditis, acute respiratory distress and myositis. There was also a higher association with mental health treatment among children who tested positive for PASC compared with those who tested negative.

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“Our study shows that the glymphatic system loses its functionality when an infection occurs in the brain,” says Federico Iovino, associate professor (docent) and group leader at the Department of Neuroscience, Karolinska Institutet and leading author of the study. “Even though we’ve only studied rats so far, we believe it’s possible that the same mechanisms are at play in humans and that the glymphatic system could be a new avenue to explore in the hopes of finding treatments to prevent neurological disabilities caused by bacterial meningitis.”

The glymphatic system was first described in 2013 as a sort of washing-machine that clears waste from the central nervous system, which comprises the brain and the spinal cord. Several neurological diseases, including Alzheimer’s and Parkinson’s disease, have since been associated with its dysfunction.

In this study, the research group of Dr. Federico Iovino and collaborators at the University of Texas Health Science Center at Houston in the U.S. and the University of Southern Santa Catarina in Brazil examined the glymphatic system in rats infected with the bacteria Streptococcus pneumoniae. S. pneumoniae is the leading pathogen causing bacterial meningitis, a potentially deadly infection that in many cases leads to permanent disabilities.

The researchers found higher amounts of bacterial waste products in the brains of rats with meningitis than in a control group. The concentrations were highest in the brain’s cerebrospinal fluid compartments. In contrast, blood tests revealed low levels of bacterial components, indicating the glymphatic system had failed to drain the brain from bacteria and associated rest products. Over time, increased signs of neuroinflammation and neuronal damage were observed, with a corresponding loss of cognitive abilities.

“About half of pneumococcal meningitis survivors suffer from neurological impairments, such as hearing loss, motor and cognitive delay and psychiatric disorders, because of neurons damaged by the infection,” Federico Iovino says. “Since damaged neurons often cannot be repaired or replaced, it is important to find ways to prevent the injury, and the first step in that direction is to understand the molecular mechanisms.”

To further their understanding, the researchers examined brain tissues and cells in detail. They zeroed in on a key fluid transporter, the aquaporin-4 (AQP4)-water channel located at the end-feet of the strings of astrocytes, which are star-shaped cells that act as housekeepers of the glymphatic system.

This water channel normally regulates fluid exchanges between the cerebrospinal fluid compartments and other areas of the brain. But what the researchers found was that during pneumococcal meningitis, the AQP4-water channel lost its natural place and connection with the blood-brain barrier vessel wall. The astrocytic end-feet had detached from the vessel walls after the astrocytes swelled in response to the neuroinflammation caused by the bacterial infection.

“It’s like a snowball effect,” Federico Iovino says. “The infection causes a buildup of toxic bacterial products which activates an immune response that leads to neuroinflammation. The inflammation triggers cellular processes that lead to a detachment of astrocytic end-feet from the blood-brain barrier walls with consequent misplacement and loss of function of the important AQP4-water channel. Combined these events result in a malfunctioning glymphatic system and consequent neuronal damage.”

The study was funded by the Karolinska Institutet Committee for Research, the Karolinska Institutet Research Foundation Grants, the Swedish Research Council, the Bjarne Ahlström Foundation for research in Clinical Neurology, the Clas Groschinsky Foundation, the HKH Crown Princess Lovisa Association for Child Care, the Magnus Bergvall Foundation, the Tore Nilson Foundation, the McGovern Medical School, The University of Texas Health Science Center at Houston, the University of Southern Santa Catarina in Brazil, the Alzheimer’s Association and the National Institutes of Health/National Institute on Aging.

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Despite the impressive power of the immune system’s complex defense network, one type of threat is especially challenging to combat. This arises when the body’s own native cells turn rogue, leading to the phenomenon of cancer. Although the immune system often engages to try to rid the body of malignant cells, its efforts are frequently thwarted as the disease progresses unchecked.The illustration shows a cancer cell (center) surrounded by immune T-cells augmented with an oncolytic (cancer-fighting) virus. A new study describes how a combination of immunotherapy and virotherapy, using myxoma virus, provides new hope for patients with treatment resistant cancers.

In new research appearing in the journal Cancer Cell, corresponding authors Grant McFadden, Masmudur Rahman and their colleagues propose a new line of attack that shows promise for treatment-resistant cancers.

The approach involves a combination of two methods that have each shown considerable success against some cancers. The study describes how oncolytic virotherapy, a technique using cancer-fighting viruses, can act in concert with existing immunotherapy techniques, boosting the immune capacity to effectively target and destroy cancer cells.

Oncolytic viruses represent an exciting new avenue of cancer therapy. Such viruses have the remarkable ability to hunt and terminate cancer cells while leaving healthy cells unharmed, as well as enhancing the immune system’s ability to recognize and terminate cancer cells.

One such virus, known as myxoma, is the focus of the current research and an area of expertise for the research group. The study shows that the use of T-cells infected with myxoma virus can induce a form of cancer cell death not previously observed.

Known as autosis, this form of cell destruction may be particularly useful against solid tumors that have proven treatment-resistant to various forms of cancer therapy, including immunotherapy alone.

“This work affirms the enormous potential of combining virotherapy with cell therapy to treat currently intractable cancers,” McFadden says.

McFadden directs the Biodesign Center for Immunotherapy, Vaccines and Virotherapy at Arizona State University.

Internal sentries

The immune system is composed of a range of specialized cells designed to patrol the body and respond to threats. The system is involved in a ceaseless arms race against pathogens, which evolve sophisticated techniques to attempt to outwit immune defenses, propagate in the body and cause disease. Cancer presents a unique challenge to the immune system as tumor cells often lack the identifying cell features that allow the immune system to attack them by distinguishing self from non-self.

Cancer cells can further short-circuit immune efforts to hunt and destroy them, through a range of evasive strategies. Researchers hope to help the immune system to overcome cancer’s notorious tactics of disguise, developing new experimental techniques belonging to a category known as adoptive cell therapy, or ACT.

Such methods often involve removing a collection of cancer-fighting white blood cells known as T-cells, modifying their seek-and-destroy capacities and reinjecting them in patients. Two forms of ACT immunotherapy are described in the new study: CAR T-cell therapy (CART) and T Cell Receptor Engineering (TCR). The basic idea in each case is the same: treating cancer with activated T lymphocytes extracted from the patient.

New method delivers one-two punch to tumor cells

The development of these therapies has been nothing short of revolutionary, and some cancer patients facing grim prospects have made remarkable recoveries following the use of immunotherapy. But techniques like CART and TCR nevertheless have their limitations and are often ineffective against advanced solid tumors. In such cases, cancer cells often manage to evade destruction by T-cells by downregulating or losing the surface antigens or MHC proteins that T-cells use to identify them.

The new study highlights the ability of immunotherapy when it is coupled with virotherapy to break through the wall of cancer resistance, specifically using myxoma-equipped T-cells. The myxoma can target and kill cancer cells directly but more usefully can induce an unusual form of T-cell directed cell death known as autosis. This form of cell death augments two other forms of programmed cancer cell death induced by T-cells, known as apoptosis and pyroptosis.

During myxoma-mediated autosis, cancerous cells in the vicinity of those targeted by the therapy are also destroyed in a process known as bystander killing. This effect can considerably enhance the dual therapy’s aggressive eradication of cancer cells, even in notoriously hard-to-treat solid tumors.

A combined myxoma-immunotherapy approach therefore holds the potential to turn so-called “cold tumors,” which fly under the immune system’s radar, into “hot tumors” that immune cells can identify and destroy, allowing CAR T-cells or TCR cells to enter the tumor environment, proliferate and activate.

“We are at the edge of discovering newer aspects of the myxoma virus and oncolytic virotherapy,” Rahman says. “In addition, these findings open the door for testing cancer-killing viruses with other cell-based cancer immunotherapies that can be used in cancer patients.”

The ability to radically reengineer oncolytic viruses like myxoma to target a range of resistant cancers provides a new frontier for the treatment of this devastating disease.

In a first-of-its-kind study funded by the National Science Foundation awarded to professor Daniel Costa (lead PI; UCSC), associate professor Stephen Trumble, Ph.D. (Baylor), professor Shane Kanatous, Ph.D. (Colorado State University), wildlife biologist Mike Goebel, Ph.D. (NOAA), and professor Daniel Crocker, Ph.D. (Sonoma State University), the PIs and Kienle (a graduate student and postdoctoral researcher at the time) set out with one shared goal: to learn more about leopard seals. Over the course of two years, the research group studied 22 leopard seals off the Western Antarctic Peninsula, an area rapidly warming and changing. They weighed and measured each seal and followed each seal’s activities and dive patterns using satellite/GPS tags.

In the study published in Frontiers of Marine Science — “Plasticity in the morphometrics and movements of an Antarctic apex predator, the leopard seal” — Kienle (first author) and the team documented the flexible behaviors and traits that may offer leopard seals the resilience needed to survive the extreme climate and environmental disturbances occurring around Antarctica.

This study greatly increases our understanding of leopard seals’ life history, spatial patterns and diving behavior,” Kienle said. “We show that these leopard seals have high variability (or, flexibility) in these different traits. Across the animal kingdom, variability is vital for animals adapting and responding to changes in their environment, so we’re excited to see high variability in this Antarctic predator.”

Among the research team’s discoveries detailed in the journal article:

Adult female leopard seals are much larger than adult males; in fact, females are 1.5 times larger and longer.

• The team measured one of the largest leopard seals ever, an adult female they nicknamed “Bigonia,” who weighed 540 kg (1,190 lbs.).
• Female-biased sexual dimorphism (where females are larger) is unusual among marine mammals, a diverse group that includes polar bears, whales, dolphins, seals and sea lions, but leopard seals are the most extreme example of female-biased dimorphism among the 130+ species of marine mammals.
• Why females are larger than males is not known, although Kienle explained other studies show that larger females are better at defending feeding areas, as well as stealing prey from smaller seals. Larger females also eat bigger, energy-rich prey, including fur seals and penguins, while males and smaller females often eat smaller prey like krill and fish. This suggests that the larger body size in adult females is beneficial and offers a selective advantage that Kienle and team will continue to explore.

From the movement data, female leopard seals spent more time “hauled out” — or coming out of the water to rest on ice or land — than males.

• Two adult female leopard seals in this study spent two weeks straight hauled-out on ice in the middle of the ocean, not eating and not getting in the water. Kienle and colleagues suggest that this two-week haul-out period is when female leopard seals give birth and nurse their pup.
• At the end of the two weeks, females return to water and begin diving for food again, and, at the same time, they likely wean their pup. It’s a short period to spend with their pups because the leopard seal is doing all of these really energetically demanding things without any food.

Male and female leopard seals swim short and long distances in both coastal and open-ocean habitats.

• One seal only traveled 46 km from where the team worked with the seal, staying in and around islands off the Antarctic Peninsula.
• Another seal, however, traveled 1,700 km during that same period away from the tagging location, swimming to an island more than a thousand kilometers away.

Leopard seals of both sexes are short, shallow divers — diving to an average of 30 meters and taking three-minute-long dives.

• Other seals can dive thousands of meters deep and hold their breath for more than 40 minutes. However, the research team recorded the longest and deepest dive ever recorded for leopard seals made by a male nicknamed “Deadpool,” who dove to 1,256 meters for 25 minutes.

“It’s interesting to see such variation [in movements and dive behavior] in a relatively small number of animals. To me, this means that leopard seals are highly flexible in their movement patterns, and that’s a really good thing in terms of adapting to changes in your environment,” Kienle said.

What’s next for this team of leopard seal biologists? Kienle said the team continues to analyze additional data from these same 22 leopard seals for publication. Kienle also is excited to compare how the leopard seals from this study compare to other populations of leopard seals across the Southern Ocean.

“I have so many more questions, and I’m excited to continue learning about leopard seals for years to come. There’s so much more to discover about this incredible Antarctic predator,” said Kienle, who leads the Comparative Ecophysiology of Animals Lab at Baylor that focuses on understanding how different animals work in the context of their environment.

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This framework or model takes low-cost data about relatively abundant species in a community and uses it to generate valuable insights on their harder-to-find neighbors. The journal Conservation Biology published the research as an Early View article on Aug. 25.

“One of the biggest challenges in monitoring biodiversity is that the species you’re most concerned about tend to be lowest in abundance or they’re the hardest species to observe during data collection,” said Matthew Farr, the lead author on the new report. “This model can be really helpful for those rare and elusive species.”

Farr, now a postdoctoral researcher at the University of Washington, helped develop the model as a doctoral student in Elise Zipkin’s Quantitative Ecology Lab in the College of Natural Science at MSU.

“There are a lot of species in the world and many of them are data deficient,” said Zipkin, an associate professor of integrative biology and director of MSU’s Ecology, Evolution and Behavior Program, or EEB. “We’re developing approaches to more quickly estimate what’s going on with biodiversity, which species are in trouble and where, spatially, do we need to focus our conservation efforts.”

After validating the model with an assist from forest-dwelling antelope in Africa, the researchers say it could be applied to a variety of other animals that meet certain criteria.

“The model doesn’t work for all types of species. It’s not a panacea,” Zipkin said. “But when it does work for a community, we can learn a lot more about member species without much data.”

The ‘magic’ of the model

For its newest model, Zipkin’s team focused on what’s called detection-nondetection data that tracks whether or not a given animal is detected in a given habitat.

“It’s basically the cheapest data and the easiest to collect,” Zipkin said. “You go to a spot, wait and see what animals are there and only need to record which species are seen.”

Researchers gather this data visually in person or with low-cost, motion-detecting camera traps that snap photos when triggered by an animal. Researchers then analyze the photos to record detection-nondetection data over time.

There are trade-offs, though. Although relatively cheap and easy to collect, detection-nondetection data doesn’t provide as much information as researchers and conservationists want. Historically, that has required intensive observational approaches such as tagging and tracking animals.

“That lets us calculate all sorts of things about the animals and their communities, but that data is expensive and hard to get,” Zipkin said. “For certain species, it’s impossible.”

The MSU team realized that, for the right animals, they could use an understanding of animal behavior and statistics to close the information gap by squeezing more insight out of detection-nondetection data.

“For some species, these are the best data you can get,” Farr said. “Now we can get more out of it.”

That may sound like magic — some of Zipkin’s colleagues have even said so — ?but there’s nothing supernatural about the model. Like much of science, it’s the result of hard work, collaboration and building on previous efforts in the field.

The story of the new model has its roots in 2003 with researchers J. Andrew Royle and James D. Nichols. The duo devised a mathematical link between the abundance of a species and the probability of detecting it.

At the time, Royle was a researcher with the U.S. Fish and Wildlife Service and Nichols was with the U.S. Geological Survey. Both are MSU alumni: Royle graduated with his bachelor’s degree in 1990 and Nichols earned his doctorate in 1976.

“It’s interesting,” said Farr, whose current adviser, Sarah Converse, also graduated with a bachelor’s degree from Michigan State before becoming an associate professor at the University of Washington. “Wherever you go in this field, people have some connection to Michigan State.”

After publishing the Royle-Nichols model, Royle joined the USGS, where he’d work with Zipkin before she joined MSU in 2014. In 2016, Zipkin’s team evolved the Royle-Nichols model to estimate things like the survival and reproduction rates for a single species using the barred owl as a case study.

Working in Zipkin’s lab with support from the National Science Foundation, Farr took the next step by linking the population dynamics of different species within the same communities.

“The model lets information from more common species inform what’s happening with the rare and elusive species,” said Farr. “The model relies on the commonalities between species, but still allows for variations.”

To develop the model, the team had to make some assumptions, like that the target species were territorial and did not travel much. The researchers then had to find real species that fit those assumptions to validate their model.

“We knew it would work for certain types of communities, but did those communities exist in real life?” Zipkin said.

“That’s one of the biggest challenges in model development,” Farr said. “You develop the model in a vacuum with simulations running under perfect conditions. You need to show what it can do in a real-world situation.”

“That’s when Tim O’Brien reached out and said, ‘I have your animals,'” Zipkin said.

The duiker data

Timothy O’Brien is a retired ecologist in Kenya who worked with the Wildlife Conservation Society, a nongovernmental organization or NGO, and an expert in camera traps. As part of what’s known as the Tropical Ecology Assessment and Monitoring program, or TEAM, he’s helped standardize how camera traps are used to make their data as powerful as possible.

He was familiar with Zipkin’s 2016 work and learned that she was expanding the model to include multiple species over multiple seasons. He suspected that forest-dwelling antelopes, notably those known as duiker, would provide the perfect test case.

Not only did duiker behavior match the assumptions of the model, but O’Brien had been helping monitor the animals for years using camera traps. Duikers presented an interesting and important conservation case.

“The duiker that live in rainforests, they are the most sought-after bushmeat in Africa,” O’Brien said. “If duiker populations are in decline, it’s usually because of people hunting for bushmeat.”

Bushmeat is meat from any wild animal and it’s an important source of food and income for many communities. But the hunting is loosely regulated and is financially incentivized by markets that sell bushmeat. The combination can be devastating for duiker populations.

With MSU’s model and TEAM’s duiker data, the team assessed the population dynamics of a total of 12 antelope species — some more abundant than others — in six national parks in Africa, where duikers are protected. The data covered time periods ranging from four to 11 years.

“We didn’t see the level of population decline in duiker you expect to see when hunting is an issue,” O’Brien said. “I would say the parks are fulfilling their function as far as duiker are concerned.”

Overall, the duiker populations were mostly stable, but the researchers did detect population declines in about 20% of the combinations of species and parks that they examined. Again, the declines weren’t so substantial to suggest that the duiker were being overhunted in the parks, but the researchers still want to understand what’s happening in those cases.

“We found that’s what causing the changes was more the differences between the parks than between the species,” Zipkin said. “We haven’t pinpointed the exact causes yet, but our results could help us do that.”

“Matt and Elise have taken this model to a whole new plane,” O’Brien said. “I’ve really enjoyed the collaboration.”

Charles Yackulic, a research statistician with the USGS, was also a contributor to the project, which was supported by NSF, WCS, Conservation International, the Smithsonian Institution and the Gordon and Betty Moore Foundation.

“This project is a great example of a university, government and NGOs working together,” Zipkin said.