Saturday, March 02, 2024

Brown bears digging up artificial forests


Study at Shiretoko World Heritage site shows unexpected interaction between animals and human-planted trees


Peer-Reviewed Publication

UNIVERSITY OF TOKYO

If you go down to the woods today. 

VIDEO: 

BROWN BEARS IN SHIRETOKO GROW TO BETWEEN 1.3 METERS AND 2.3 METERS TALL AND CAN WEIGH UP TO 400 KILOGRAMS. THEIR SIZE AND BULK MEAN THAT THEY NEED A PLENTIFUL SUPPLY OF FOOD, ESPECIALLY BEFORE HIBERNATION. CICADA NYMPHS ARE NOT TYPICALLY PART OF A BEAR’S DIET, BUT HAVE PROVED POPULAR WITH LOCAL BROWN BEARS LIKE THIS MOTHER BEAR AND HER CUB.

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CREDIT: 2024 TOMITA AND HIURA




Brown bears foraging for food in the Shiretoko Peninsula of Hokkaido, Japan, have been disrupting tree growth in artificial conifer forests, according to a new study. Researchers compared soil and tree samples from human-forested plots with samples from natural forests. They found that the bears’ digging for cicada nymphs damaged tree roots and altered the nitrogen content of the soil, which in turn limited the diameter growth of trees. The phenomena of bears digging for cicadas, an unusual food source, appears to be restricted to human-planted conifer forest; diversely vegetated natural forest was unaffected. Bears in Hokkaido sometimes suffer from sparse food supplies, but it is not known if this is the reason for their cicada search. These results are important for animal conservation and efforts to return used land to a wild state, highlighting the value of recreating diverse local ecosystems which can support natural wildlife behavior. 

On the northeastern tip of Hokkaido, Japan’s northernmost main island, sits the Shiretoko Peninsula, and within it the Shiretoko National Park. Designated a World Nature Heritage site, thanks to its thriving ecosystem and diverse wildlife, the peninsula is home to Japan’s largest land animal, the brown bear. It is estimated that almost 500 bears live within the 70-kilometer-long and 25-km-wide strip, making it one of the highest densities of brown-bear populations in the world. Bear numbers in Hokkaido have been gradually recovering since the 1990s, when conservation efforts began in earnest after decades of unchecked culling. 

Rather than being an isolated wilderness, thousands of people live and work in the Shiretoko Peninsula, and it is also a popular tourist destination. Since the 1970s, residents and local government have been planting conifers, such as larch and spruce, on abandoned farmland as a way to help return the area to its original forested state. However, this effort has led to some unusual behavior from the other larger inhabitants. Assistant Professor Kanji Tomita from Kochi University and Professor Tsutom Hiura from the University of Tokyo have been studying how brown bears interact with these human-made forests and found that the bears behave differently than when in their natural woodland. 

“In our latest study, we found that brown bears have been negatively impacting the growth of replanted larch conifer trees. They come to the new forests to dig for cicada nymphs, a behavior we haven’t seen in natural woodland or heard reported elsewhere in the world,” said Hiura from the Graduate School of Agricultural and Life Sciences. “While mammalian digging behavior in natural ecosystems has typically been seen as having a positive influence, our research shows that the outcome is different in anthropogenic (human-made) landscapes.” 

This latest research is a follow-up to a previous study by Tomita and Hiura, in which they first discovered the bears’ penchant for cicada nymphs. The pair were surprised that the bears dug for the cicadas exclusively in human-made conifer forest, not in natural woodland, and noticed the damage being done to the roots of the trees in the process. So, they decided to assess the impact of the bears’ behavior on the artificial forest’s ecosystem. 

The researchers compared soil samples, tree needles and tree core samples from dug and undug larch conifer forests in Shiretoko. Finding undug plantations was a challenge, so they had to collect samples from conifer forests which had an underlying layer of bamboo, which the bears avoided. They found that digging activity decreased the biomass of fine roots, soil water content and nitrogen availability. This resulted in the width, or radial growth, of the trees being less in dug forests than in the untouched forests.

“Previous studies have not considered the human impacts of forestation efforts because data were collected from natural ecosystems. So, this study is important for wildlife conservation and understanding the roles of large mammals in anthropogenic landscapes,” explained Tomita. “Referring to knowledge from only pristine ecosystems is not sufficient. To develop more appropriate management strategies for large carnivores, we need to further understand their ecosystem roles in human-made landscapes.”

“Rather than rely on artificial afforestation (converting land into forest) methods, this research highlights the necessity of introducing natural regeneration methods by seed dispersal from the surrounding area,” said Hiura. “This will not only restore ecosystems with high species diversity and rich interactions among animals and plants, but it will also be beneficial to human society in the long term.”

Bears in Shiretoko and other parts of Japan have recently struggled to find enough of their staple foods, such as salmon and nuts, to survive. Increased human development and portioning off of land, along with variable harvests due to climate change, have exacerbated their situation. This increases the risk of potentially dangerous encounters, for both people and bears, as they wander into more populated towns, campsites and fishing areas. Enriching the bears’ natural habitat and planning new forests based on ecological research will hopefully help bears and humans to coexist safely and thrive in this beautiful environment.

The name Shiretoko comes from an Ainu phrase meaning “End of the Earth.” The indigenous Ainu people of northern Japan have long had a close relationship with bears, which in local religion were seen as being a mountain deity in disguise and considered sacred.

CREDIT

2024 Kanji Tomita

Paper Title:

Kanji M. Tomita and Tsutom Hiura. Brown bear digging decreases tree growth: Implication for ecological role of top predators in anthropogenic landscapes. Ecology. DOI: 10.1002/ecy.4266.

Funding:

This research was partly supported by JSPS to T.H. (no. 21H05316).

Useful Links
Graduate School of Agricultural and Life Sciences: https://www.a.u-tokyo.ac.jp/english/ 

Forest Ecosystem Management Lab: http://www.fes.es.a.u-tokyo.ac.jp


About the University of Tokyo
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Orcas demonstrating they no longer need to hunt in packs to take down the great white shark


Study reveals “astonishing” footage of new predation tactics of the orca, raising further concerns about the marine ecosystem

Peer-Reviewed Publication

TAYLOR & FRANCIS GROUP

Great White Shark carcass 

IMAGE: 

PHOTO OF GREAT WHITE SHARK CARCASS.

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CREDIT: CREDIT: CHRISTIAAN STOPFORTH, DRONE FANATICS SA




An orca (killer whale) has been observed, for the first-ever time, individually consuming a great white shark – and within just two minutes.

“The astonishing predation, off the coast of Mossel Bay, South Africa, represents unprecedented behavior underscoring the exceptional proficiency of the killer whale”, remarks Dr. Alison Towner from Rhodes University, who led an international research team into the discovery.

Their findings are published today in the peer-reviewed African Journal of Marine Science.

The groundbreaking insight is the latest from Dr. Towner and the team, who, in 2022 in the same journal, revealed that a pair of orca were hunting and killing great white sharks off the coast of South Africa since 2017 – managing to drive large numbers of the sharks from their natural aggregation sites.

Orcas are generally known to work together to catch large prey like sea lions, seals, and even other whales – and of course, sharks too. By hunting together, they can surround prey and use their combined intelligence and strength to attack. 
They can hunt large animals individually. However, this is the first such occurrence on what is one of the world's largest predators – the great white.

“Again, as previously in South Africa, the orcas are exhibiting a strong preference for extracting and consuming the lipid-rich livers of white sharks – a specialized feeding behavior,” explains Dr. Towner, who has studied great white sharks for the last 17 years, learning about their movement patterns through tagging data.

“But what we witnessed was an orca, nicknamed Starboard – due to his collapsed dorsal fin – performing alone to incapacitate and consume a white shark within an astounding two-minute timeframe.

“Starboard was observed preying on a 2.5-meter (8.2 feet) juvenile white shark, later carrying the shark’s liver in its mouth past a boat.

"This sighting revealed evidence of solitary hunting by at least one killer whale, challenging conventional cooperative hunting behaviors known in the region.

“These are groundbreaking insights into the predatory behavior of this species, and our findings significantly contribute to the global understanding of Killer Whale predation dynamics, enhancing knowledge of marine ecosystems and predator-prey relationships”.

During the observed interactions of this event, at least two white sharks were killed, as evidenced by the discovery of a second carcass measuring 3.55 meters (11.6 feet) nearby.

“The study raises critical questions about the impact of killer whale predation on shark populations in South Africa,” Dr. Towner says. “The displacement of various shark species due to killer whale presence may have implications for mesopredator release and potential trophic changes in the marine ecosystem.”

Understanding the ecological dynamics of killer whale predation is paramount for marine conservation efforts. The authors state that this event “underscores the urgent need for adaptable conservation strategies and vigilant ecological monitoring amidst changing environmental conditions”.

Founding Director and Principal Scientist at Sea Search Research & Conservation, and at the Department of BotZoo, University of Stellenbosch, Dr. Simon Elwen, is an expert in the ecology, behavior, and conservation status of whales.

Commenting on the importance of Dr. Towner’s team’s findings, he says: “The observations reported here add more layers to the fascinating story of these two killer whales and their capabilities. As smart, top predators, killer whales can rapidly learn new hunting techniques on their own or from others, so monitoring and understanding the behaviors used here and by other killer whales in South Africa is an important part of helping us understand more about these animals.”

The involvement of land-based observers, tourists on vessels, and collaborating institutions played a “pivotal role” in capturing this crucial data and footage of the predation events.

This particular event “underscores the benefits of citizen science as a collaborative effort between researchers, tourists, and organizations”, the authors state.

Esther Jacobs, from the marine conservation initiative, Keep Fin Alive, recounts her experience witnessing the predation: “Upon reaching Mossel Bay’s Seal Island, the scent of shark liver oil and a noticeable slick indicated a recent kill. Tracking Port and Starboard near the island, they remained separated.

“Witnessing a white shark's fin break the surface initially sparked excitement, but that turned to a somber realization as Starboard swiftly approached. The moment Starboard rapidly preyed on my favorite shark species was both devastating and intensely powerful.”

Co-author Dr. Primo Micarelli, from the Shark Studies Centre and Siena University, was on board the vessel White Shark Africa and commented: “Over two decades of annual visits to South Africa, I've observed the profound impact these killer whales have on the local white shark population. Seeing Starboard carry a white shark's liver past our vessel is unforgettable.

“Despite my awe for these predators, I'm increasingly concerned about the coastal marine ecology balance”.

Concluding, Dr. Towner highlights that the new findings on killer whales provide important further insights into how adaptable mammalian predators specialize and diverge ecologically.

“The presence of these shark-hunting killer whales possibly ties into broader ecosystem dynamics. Rapid developments in this phenomenon, make it challenging for science to keep pace, prompting us to publish these timely short communications."

 


Proposed reporting system could help avert bank runs


Strategic disclosure of both good and bad news can inform regulators without scaring depositors

Peer-Reviewed Publication

UNIVERSITY OF TEXAS AT AUSTIN




Last year’s failures of Silicon Valley Bank and two other financial institutions — after panic-driven runs on deposits — have fueled a longstanding debate in bank regulation: How much transparency is too much?

Regulators need detailed disclosure of a bank’s balance sheet to be able to intervene before it fails. But too much disclosure could spook depositors to flee prematurely from a bank that could be saved.

New research from Texas McCombs identifies a potential happy medium: an “optimal reporting system” that might help to avert future crises.

Under his proposed system, “runs like the runs on Silicon Valley Bank and the other two banks would be less likely or less catastrophic,” says Ronghuo Zheng, associate professor of accounting.

Which Value To Report?

A major controversy with the current system, he says, has been its use of fair-value accounting. This standard reports a bank’s assets at their current fair market values — rather than their original cost.

But there’s a significant exception to the standard: Banks aren’t required to report so-called HTM securities at fair value. Those are bonds meant to be held to maturity, such as 10-year U.S. Treasury bonds.

Under this exception, a bank reports a $100 T-bond at $100. But in bond markets, its fair value can fluctuate. On Feb. 13, a $100 10-year T-bond was worth only $97.16. That’s a loss of $2.84.

Normally, such losses are only on paper, because the bank isn’t planning to sell the bonds. But in March 2023, Silicon Valley Bank did have to start selling them to pay off a few large depositors who were withdrawing their money. That news spooked other depositors to withdraw, forcing the bank to unload even more bonds — at a loss. When the run was over, its losses added up to $1.8 billion.

That scenario could have been avoided if the bank had reported the market value of those bonds, Zheng says. Regulators could have foreseen problems and acted before a run began.

“Classifying assets as HTM instead of fair value allowed banks to hide unrealized paper losses,” he says. “It triggered panic among investors, once banks were forced to sell these assets at significantly lower prices than reported on the balance sheet.”

Reporting To Prevent Panics

What would an optimal reporting system look like? Using a widely used bank-run model, Zheng and Gaoqing Zhang of the University of Minnesota calculated that an optimal system would spotlight the riskiest banks while shielding less risky ones from runs. It would do that by requiring full disclosure in some scenarios but not in others.

  • If a bank had paper losses on HTM securities, it would have to report them, alerting regulators to potential trouble.
  • If it had paper gains on HTM securities, it could report them to reassure depositors — but only up to a certain level.

Each bank would have its own threshold, tailored to its individual risk of runs and its exposure to larger shocks such as recessions. It would not report gains above that level.

Says Zheng, “The optimal reporting system requires full disclosure of all unfavorable news but disclosure of favorable news only below some threshold.”

Why set a threshold for good news? Zheng says it’s to protect medium-risk banks from needless panics.

If some banks report large asset gains and others report only moderate gains, depositors might doubt the soundness of the latter — even though their risk levels are only medium. By limiting how much all banks can report, Zheng’s system lumps low- and medium-risk banks together in depositors’ eyes. It protects solvent banks from unwarranted and destabilizing runs.

“We only want to report the really bad banks,” Zheng says. “If you are not too bad, you can stay silent.”

 

Study detects cognitive changes in older drivers using in-vehicle sensors


Project provides first step toward widespread use of low-cost, early warning system

Peer-Reviewed Publication

FLORIDA ATLANTIC UNIVERSITY

In-vehicle Sensors 

IMAGE: 

THE DRIVER-FACING CAMERA IS MOUNTED IN THE LEFT CORNER OF THE WINDSHIELD AND IS DIRECTED TO THE DRIVER’S FACE TO ANALYZE HIS/HER BEHAVIOR AND FACIAL EXPRESSIONS. THE FORWARD-FACING CAMERA IS MOUNTED UNDER THE REARVIEW MIRROR AND IS USED TO RECORD EVENTS EXTERNAL TO THE VEHICLE.

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CREDIT: JINWOO JANG, PH.D., FAU COLLEGE OF ENGINEERING AND COMPUTER SCIENCE


An estimated 4 to 8 million older adults with mild cognitive impairment are currently driving in the United States, and one-third of them will develop dementia within five years. Individuals with progressive dementias are eventually unable to drive safely, yet many remain unaware of their cognitive decline.

Currently, screening and evaluation services for driving can only test a small number of individuals with cognitive concerns, missing many who need to know if they require treatment.

Nursing, engineering and neuropsychology researchers at Florida Atlantic University are testing and evaluating a readily and rapidly available, unobtrusive in-vehicle sensing system they have developed. This technology could provide the first step toward future widespread, low-cost early warnings of cognitive change for this large number of older drivers in the U.S. and elsewhere.

In their study, published in the journal BMC Geriatrics, they are systematically examining how this system could detect anomalous driving behavior indicative of cognitive impairment. Few studies have reported on the use of continuous, unobtrusive sensors and related monitoring devices for detecting subtle variability in the performance of highly complex everyday activities over time. This significant proportion of older drivers constitutes a previously unexplored opportunity to detect cognitive decline. 

“The neuropathologies of Alzheimer’s disease have been found in the brains of older drivers killed in motor vehicle accidents who did not even know they had the disease and had no apparent signs of it,” said Ruth Tappen, Ed.D., principal investigator, senior author and the Christine E. Lynn Eminent Scholar and Professor, FAU Christine E. Lynn College of Nursing. “The purpose of our study arose from the importance of identifying cognitive dysfunction as early and efficiently as possible. Sensor systems installed in older drivers’ vehicles may detect these changes and could generate early warnings of possible changes in cognition.”

The study uses a naturalistic longitudinal design to obtain continuous information on driving behavior that is being compared with the results of extensive cognitive testing conducted every three months for three years. A driver facing camera, forward facing camera, and telematics unit are installed in the vehicle and data is downloaded every three months when the cognitive tests are administered.

Researchers are gauging abnormal driving such as getting lost, ignoring traffic signals and signs, near-collision events, distraction and drowsiness, reaction time and braking patterns. They also are looking at travel patterns such as number of trips, miles driven, miles on the highway, miles during the night and daytime, and driving in severe weather.

The in-vehicle sensor network developed by FAU researchers in the College of Engineering and Computer Science, uses open-source hardware and software components to reduce the time, risks and costs associated with developing in-vehicle sensing units. In-vehicle sensor systems are kept simple and compact by minimizing complex wiring, limiting the size of the sensing units, and limiting the number of sensors in a vehicle to support the unobtrusiveness of in-vehicle sensors. Each in-vehicle sensor system is comprised of two distributed sensing units: one for telematics data and the other for video data.

Inertial measurement unit data is processed to determine hard braking, hard accelerations and hard turns and GPS data. It also includes a timestamp, latitude, longitude, altitude, course over ground and the number of communicating satellites.

The video unit has built-in artificial intelligence functions that analyze video in real-time. The driver-facing camera is mounted in the left corner of the windshield and is directed to the driver’s face to analyze his/her behavior and facial expressions. The forward-facing camera is mounted under the rearview mirror and is used to record events external to the vehicle.

Driver-facing indices include face detection, eye detection (open or closed), yawning, distraction, smoking and mobile phone use. Behavior indices include traffic sign detection (running a red light), object detection (pedestrian, cyclists, curbs, barriers or nearby vehicles), lane crossing, near-collision and pedestrian detection.

“These travel-pattern-related driver behavior indices are known to be indicative of the changes in older drivers’ cognition and physical functions since they tend to incorporate deliberate avoidance strategies to compensate for age-related deficits,” said Tappen. “Driver behavior indices are evaluated for each driver and are summarized on a daily, weekly and monthly basis and are classified into four categories.”

A total of 460 study participants will be recruited from Broward and Palm Beach counties in Southeast Florida and are classified into three diagnostic groups: mild cognitive impairment, early dementia and unimpaired (normal). The Louis and Anne Green Memory and Wellness Center operated by FAU’s College of Nursing serves as the testing site for a clinical battery including assessments of cognition, functioning in daily activities and mood (depression), and an additional set of tests including executive function and attention.

“The innovation of our research project lies in the unobtrusive, rapidly and readily available in-vehicle sensing and monitoring system built upon modern open-source hardware and software using existing techniques to develop and customize the components and configure them for this new purpose,” said Tappen.

The study is supported by a grant from the National Institute on Aging, National Institutes of Health (1R01AG068472) awarded to Tappen.

- FAU -

About the Christine E. Lynn College of Nursing

FAU’s Christine E. Lynn College of Nursing is nationally and internationally known for its excellence and philosophy of caring science. The College was ranked No. 11 nationwide by US News and World Report in 2021 for “Best Online Master’s in Nursing Administration Programs” and No. 32 for the “Best Online Master’s in Nursing Programs.” In 2020, FAU graduates earned a 95.9% pass rate on the National Council Licensure Examination for Registered Nurses (NCLEX-RN®) and a 100% AGNP Certification Pass Rate. The baccalaureate, master’s and DNP programs at Florida Atlantic University’s Christine E. Lynn College of Nursing are accredited by the Commission on Collegiate Nursing Education. The College is the only one in the U.S. to have all degree programs endorsed by the American Holistic Nursing Credentialing Corporation.

 

About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 30,000 undergraduate and graduate students across six campuses located along the southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, FAU embodies an innovative model where traditional achievement gaps vanish. FAU is designated a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report and a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. For more information, visit www.fau.edu.