It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Sunday, February 05, 2023
Decline in wild bee species richness associated with honey bee abundance in an urban ecosystem
A new study published in PeerJ Life & Environment has provided insights into how western honey bees (Apis mellifera L.) in urban areas may represent a new threat to wild bee communities
A new study published in PeerJ Life & Environment has provided insights into how western honey bees (Apis mellifera L.) in urban areas may represent a new threat to wild bee communities. On the Island of Montréal, Canada there has been a particularly large increase in beekeeping across the city.
The study examined the wild bee communities and floral resources across a gradient of honey bee abundances in urban greenspaces in 2020, and compared the bee communities at the same sites before and after the large influx of honey bees. The research found a negative relationship between urban beekeeping, pollen availability, and wild bee species richness. It also found that honey bee abundance had the strongest negative effect on small wild bee species richness.
The study found:
Wild bee populations can fluctuate largely in space and time, however, the analyses of the bee and floral community in 2020, and the comparison to the bee community in 2013, strongly suggests a negative relationship between high-density urban beekeeping and wild bee richness.
Urban floral communities are often dominated by exotic and cultivated plants, and native bees tend to prefer native plants, exotic bees are thought to have an advantage in urban environments
Small bee species (ITS <2.25 mm) were influenced by the presence of managed honey bees. The analyses of the small wild bee community (57% of all wild bees sampled) showed a decline in richness with honey bee abundance across both sites and years, not seen in the large bee community.
Despite the natural spatiotemporal variation in bee community composition and the complexity of competitive interactions among bee species, the study detected a significantly negative relationship between honeybee abundance and wild bee richness. However, the study is correlative by design, and provides only indirect evidence of exploitative competition.
Negative correlations between honey bee populations and wild bee diversity cannot be interpreted as direct evidence for competitive exclusion. To complement field studies, more experimental investigations of the fitness impacts of honey bees on wild bee species over multiple years are needed to further our understanding of interspecies competition, and provide reliable estimates of the carrying capacity of cities for honey bees.
The government is giving the University £100,000 to improve measurement of CO2 streams from sites such as at power plants and factories. The Energy and Bioproducts Research Institute (EBRI) at Aston University is to develop a comprehensive guide based on industry and academic expertise.
Industrial decarbonisation will play a major role in achieving the UK’s 2050 ambitious net zero emissions target, however current measurement guidelines need to be improved.
The six-month project will be a collaboration between EBRI researchers and the company Progressive Energy and the Energy Institute. Progressive Energy will work alongside potential end-users and the Energy Institute will help to ensure the final guidelines are clear.
The work is being led by Dr Paula Blanco Sanchez, who has more than 15 years of experience in bioenergy. She said: “This funding will help Aston University to address a major gap in the decarbonisation pathway. It will contribute to the UK’s net zero target and is another example of how the University is using its expertise to tackle real world problems.
“Our experts in EBRI will provide research, industrial experience and knowledge in areas such as gas measurement, metric and analytics, life cycle and techno-economic assessments, and thermal conversion processes.”
The funding has been awarded by the Industrial Decarbonisation Research and Innovation Centre (IDRIC) to achieve the net zero ambition set out in the UK Industrial Decarbonisation Strategy (2021).
Bryony Livesey, challenge director, Industrial Decarbonisation Challenge, UKRI, said: “The announcement of this funding continues to build upon IDRIC’s whole system approach to decarbonising industry, enabling the UK to remain at the forefront of a global low-carbon future. These successful Wave 2 projects will build evidence on a range of areas from economics and emissions to skilled jobs and wider net zero policy, supporting UK’s green growth and net zero ambitions.”
It’s hoped the Aston University project will lead to future collaborations and funding to support UK industry to decarbonise their businesses.
Founded in 1895 and a university since 1966, Aston is a long-established university led by its three main beneficiary groups – students, business and the professions, and the West Midlands region and wider society. Located in Birmingham at the heart of a vibrant city, the campus houses all the University’s academic, social and accommodation facilities for our students. Professor Aleks Subic is the Vice-Chancellor & Chief Executive.
In 2022 Aston University was ranked in the top 25 of the Guardian University Guide, based on measures including entry standards, student satisfaction, research quality and graduate prospects. The Aston Business School MBA programme was ranked in the top 100 in the world in the Economist MBA 2021 ranking.
Award-winning: ”Teaching Public Service in the Digital Age”
IMAGE: INES MERGEL, PROFESSOR OF PUBLIC ADMINISTRATION AND DIGITAL GOVERNANCE AT THE UNIVERSITY OF KONSTANZ, RECEIVES A SCHMIDT FUTURES INNOVATION FELLOWSHIP.view more
CREDIT: UNIVERSITY OF KONSTANZ
"We found during the Covid-19 pandemic that the digital transformation of government can only succeed if both managers and staff develop the corresponding digital skills and capabilities," explains Ines Mergel, Professor of Public Administration and Digital Governance at the University of Konstanz. "Unfortunately, these are currently not taught in public affairs programmes."
This is why she co-initiated the project "Teaching Public Service in the Digital Age" together with David Eaves, associate professor at the University College London – Institute for Innovation and Public Purpose, Tom Steinberg (a former CDO in the UK government) and Amanda Clarke, associate professor at Carleton University (Canada). The open access syllabus is designed to train professors who teach students in public administration and public policy programmes the skills required for the digital age. The project team developed teaching units ranging from components of digital systems to data and legal hurdles.
In collaboration with other professors and experts, they created an Open Educational Resource – a set of open access teaching materials that goes beyond the usual online curricula. The instructors explain their methods in detail, provide questions to discuss in class and give relevant background information. They also prepare case studies and provide videos from their own lectures. The materials include global experiences and research findings that, due to their multidisciplinary nature, can be adapted to meet the needs of teachers from different backgrounds.
About the Schmidt Futures Innovation Fellows Program Schmidt Futures, a philanthropic initiative of Eric and Wendy Schmidt, aims to bring talented people together in networks to prove out their ideas and solve hard problems in science and society. The Innovation Fellows Program supports extraordinary mid-career individuals and teams with ideas to leverage technology thoughtfully to solve important societal challenges. The program aims to serve as a force multiplier for their ideas and to bring them together into a community to support one another and mentor others.
Other supporters including Bloomberg Philanthropies are also providing funds for the project. Ines Mergel and David Eaves will join a cohort of leaders working across multiple sectors to drive impact, who connect and support one another's work and ideas, "We are so happy to receive this support for our project!", Ines Mergel says. "Volunteers have already translated the curriculum into several other languages. Now we can use the funds to support additional translations and offer even more master's classes in the train-the-trainer format. In this format, we introduce teachers to the content and work together on how they can teach and adapt the content to their local context." Further research projects are also planned.
Key facts:
Ines Mergel, Professor of Public Administration and Digital Governance at the University of Konstanz, and David Eaves, associate professor at University College London (UCL) – Institute for Innovation and Public Purpose, each receive a Schmidt Futures Innovation Fellowship. Also centrally involved in the project are Tom Steinberg and Amanda Clarke, Carleton University (Ottawa, Canada).
Their project, "Teaching Public Service in the Digital Age," is supported by Schmidt Futures and Bloomberg Philanthropies (et al.).
"Time is not what it used to be": Children and adults experience time differently
Time can do tricks. Many of us experienced the illusion that those long summers during childhood felt so much longer than the same 3 months feel like now as an adult.
EÖTVÖS LORÁND UNIVERSITY (ELTE), FACULTY OF SCIENCE
IMAGE: RESEARCHERS AT EÖTVÖS LORÁND UNIVERSITY HAVE INVESTIGATED WHETHER THE PERCEPTION OF TIME CHANGES WITH AGE, AND IF SO, HOW, AND WHY WE PERCEIVE THE PASSAGE OF TIME DIFFERENTLY. THEIR STUDY WAS PUBLISHED IN SCIENTIFIC REPORTS.view more
CREDIT: PHOTO: NÁDASDY ZOLTÁN
Researchers at Eötvös Loránd University have investigated whether the perception of time changes with age, and if so, how, and why we perceive the passage of time differently. Their study was published in Scientific Reports.
Time can do tricks. Many of us experienced the illusion that those long summers during childhood felt so much longer than the same 3 months feel like now as an adult. While we can argue why one summer may appear longer than the other and how the percept of time can compress and dilate durations depending on various factors, we can easily set up an experiment to gain more insights.
The researchers just did that. They asked how eventfulness affects our duration estimates when probing at different milestones during our cognitive development. They set aside three age groups, 4-5, 9-10, and 18 years and older, and made them watch two videos, 1 minute each. The two videos were extracted from a popular animated series, balanced in visual and acoustic features, except for one feature: eventfulness. One video consisted of a rapid succession of events (a policeman rescuing animals and arresting a thief), and the other was a monotonous and repetitive sequence (six shady prisoners escaping on a rowing boat). The researchers played the two clips in a balanced order of 50%, watching the eventful first. After watching both videos, they asked only two questions: "Which one was longer?" and "Can you show the durations with your arms?" Easy to understand questions even for a 4-year-old.
The results showed a strong bias in each age group but for pre-kindergarteners, surprisingly, in the opposite direction.
While more than 2/3rd of pre-kindergarteners perceived the eventful video as longer, 3/4th of the adult group felt the same about the uneventful video. The middle group expressed a similar but more moderate bias than the adult. By the inclusion of the middle group (9-10-year-olds), the inflection point could be estimated around the age of 7. Regarding the arm-spread orientation, and distance, there was an increasing trend of using horizontal arm spreading with age. While pre-kindergarten-age kids used 50-50% vertical and horizontal gestures, by school age, that ratio changed to 80-90% in favor of horizontal arm expressions.
The result is unexpected because none of the biological models of time perception could have predicted it. How can we interpret this result? Biological models of time perception fall under two categories: pacemaker-like neurons in the brain and neurons that display a declining firing rate with time. Still, "who" would interpret those signals in the brain remains elusive. Both model classes assume a continuous age-dependent improvement with age. However, this is not what the researchers found. Instead, what they found was a switch of perceived duration ratios between the youngest and the two older groups, with a turning point at 7. How can we explain such a bias reversal?
The authors called upon the concept of heuristics, introduced in cognitive science by Amos Tversky and Daniel Kahneman. They define heuristics as mental shortcuts or proxies that enable one to make quick decisions. To understand why we need heuristics for comparing durations, let us look at what else we can rely on. Since the brain has neither a reliable central clock nor a direct sensory mapping of durations, unlike distances or pitch, we must use a proxy. A proxy to "duration" is something concrete yet related to the time content, like "Which one can I talk more about?". If the first video was packed with actions, they could tell a lot about it, thinks the 5-year-old. While the other movie could be summarized with a single verb, such as "rowing". The eventful video consisted of three episodes, a perfect example of a story. The uneventful video, in contrast, had no episodes and no storyline. In terms of heuristics, the difference can be captured by representativeness heuristics. The eventful video had more representative story examples than the uneventful one. Therefore, relying on a representativeness heuristic, the kindergarteners would feel the eventful video was longer (see the left side of the figure).
If this notion of duration provides a good proxy for "time", why do we switch to another system at 7? The researchers argue that the answer is switching to another class of heuristics, namely, sampling heuristics. At around the age of 6 to 10, kids learn the concept of "absolute time". We all rely on the concept of absolute and universal time when we make appointments, organize our tasks, and follow timelines. All these actions reinforce the concept of universal time that is independent of the observer and entirely consistent with Newton's classical mechanics. We start thinking about time as a physical entity, independent of the events that it connects, and we become aware that our subjective experience of time as observers may change or be a subject of illusions. The best we can do to eliminate subjectivity is to check the flow of time.
We can check the flow of time by frequently sampling it. Looking at the clocks or just staring out the window and watching the traffic flow. The more often we check, the more reliable the estimate we get. However, our brain is not always available for tracking time. When our attention is occupied with another task, then this sampling of the absolute time may skip cycles. In contrast, when waiting for somebody who is late for an appointment, time slows down as the brain counts the seconds while impatience and irritation increase.
In light of these heuristics, representativeness, and sampling, let us see how we sample the absolute time when we are asked to guess the duration of an exciting and captivating video versus a boring one. When watching a captivating movie, the mind is completely immersed in the story because the sequence of actions unfolds so fast that one does not have time to think about anything else, such as life, work, or a to-do list. Instead, the mind is hijacked by the alternative reality of the movie plot. In contrast, when watching a boring movie, one is going to check the watch or think about where else one could be at that time, and all these distractions enable us to sample the flow of absolute time (right side of the figure). Hence, the two types of heuristics explain the bizarre switch at about age 7 and the persistent bias that the boring meetings appear longer than they are, which stays with us for the rest of our life.
While the enigma of time has been and will continue to intrigue the human mind, it is essential to realize that these fundamental concepts, like time and space, are more complex than we can pin down by certain types of neurons in the brain. To wrangle such abstract concepts, one needs to connect all biological and cognitive pieces. Will we ever complete that jigsaw puzzle? Only time will tell.
Following the Russian invasion of Ukraine from February 24, 2022, energy prices rose by up to 20% worldwide for five months. WTI crude oil was $92.77 per barrel on February 24, 2022, but rose and averaged $106.96 (+15.3%) from February 28 to August 3. Furthermore, energy consumer price indexes (energy CPI) increased consecutively for five months, when comparing February and July, in OECD (18.0%) and G-7 (18.9%) countries, hitting their highest year-over-year growths ever since tracking began in 1971 in OECD (40.70%) and G-7 (39.43%) in June 2022.
Because energy use is merely an intermediate input, rising energy prices may have little impact on real gross domestic product (GDP). Meanwhile, rising energy prices may decrease social surplus, slowing economic growth. When energy prices rise, consumers primarily buy less durable goods, e.g., cars and new houses, and firms may reduce their investment spending due to uncertainty. Also, because fossil fuels are primarily used as intermediate inputs upstream in the supply chain, higher energy prices lead to higher global costs (due to spillover effects).
For such a shock analysis, input-output analysis (IOA) is favored to examine the spillover effects in the supply chain. In particular, the Leontief quantity model—the most popular demand-driven model—is the de-facto standard for both demand and supply analysis. However, it has issues. The model is not theoretically consistent with the supply analysis, and, more importantly, it is likely to overestimate monetary damage because price and quantity are inelastic.
A new study from researchers at Kyushu University finds that if the price increases by 20% in Russia’s mining and quarrying (M&Q) sector alone, there will be almost no effects globally. That is, global prices will rise by only 0.13% across all sectors globally (weighted average), reducing social surplus by 0.28% of the pre-invasion monthly GDP ($22,295 million per month).
Meanwhile, if prices increased by 20% globally in every M&Q sector, global prices will rise by 3.15% across all sectors, reducing the social surplus by 6.83% of the pre-invasion monthly GDP ($551,080 million per month). This case is roughly equivalent to Russian M&Q (energy) prices being five times higher (+497%), demonstrating the magnitude of geopolitical risk.
Research Lecturer Michiyuki Yagi and Professor Shunsuke Managi in the Urban Institute and the Department of Civil Engineering, Kyushu University, reached these conclusions by updating the world IO table to 2021 values (56 sectors in 44 countries) and analyzing the two scenarios above using the Leontief price model with the exogenous price elasticity of demand at the monthly level, a method developed by the authors in 2020*. As advantages, this model is theoretically suitable for supply analysis and will not overestimate monetary damages because price and quantity are perfectly elastic to each other.
Regarding the policy implications, with a price change of only 20%, Russia’s energy sector alone has little global impact because the economic scale is relatively small. Second, if energy prices rise globally, the most affected are three energy-related sectors (M&Q, coke/petroleum, and electricity and gas supply), metal, mineral products, electrical equipment, chemical products (manufacturers), air transport, and construction (service sectors). Finally, if energy prices rise, policymakers should focus on the downstream sectors of buyers or consumers. They will be more damaged than sellers or producers as they have to buy fewer quantities at higher prices. In terms of energy (fossil fuel) prices, the 2022 Russian invasion of Ukraine (was an economic shock that) cost consumers or buyers (in the world) primarily 2.85% of the pre-invasion annual GDP ($2.7 trillion) in five months following the invasion.
The results of this research was published online in the journal Economic Analysis and Policy (the Economic Society of Australia) on January 4, 2023.
For more information about this research, see “The spillover effects of rising energy prices following 2022 Russian invasion of Ukraine,” Michiyuki Yagi and Shunsuke Managi, Economic Analysis and Policy. https://doi.org/10.1016/j.eap.2022.12.025
*Yagi, M., Kagawa, S., Managi, S., Fujii, H., Guan, D., 2020. Supply Constraint from Earthquakes in Japan in Input-Output Analysis. Risk Analysis. vol. 40 (9), pp.1811-1830. https://doi.org/10.1111/risa.13525
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About Kyushu University
Kyushu University is one of Japan’s leading research-oriented institutes of higher education since its founding in 1911. Home to around 19,000 students and 8,000 faculty and staff, Kyushu U's world-class research centers cover a wide range of study areas and research fields, from the humanities and arts to engineering and medical sciences. Its multiple campuses—including the largest in Japan—are located around Fukuoka City, a coastal metropolis on the southwestern Japanese island of Kyushu that is frequently ranked among the world’s most livable cities and historically known as a gateway to Asia.
IMAGE: AN INTERNATIONAL TEAM OF RESEARCHERS DISCOVERED A NEW SPECIES OF SPINY-THROATED REED FROG WHILE CONDUCTING AN AMPHIBIAN SURVEY IN TANZANIA'S UKAGURU MOUNTAINS.view more
CREDIT: CHRISTOPH LIEDTKE
Researchers discovered a new species of frog in Africa that has an unusual trait: it’s completely silent.
The Ukaguru spiny-throated reed frog does not croak, sing or ribbit. Found in Tanzania’s Ukaguru Mountains for which it is named, Hyperolius ukaguruensis is among the few frogs around the world that do not vocalize to other frogs.
The new species belongs to a group of “spiny throated” reed frogs, which true to their name have tiny spines on the male’s throat. Since they can’t rely on sound to recognize members of their species, they might use spines instead.
“It’s a very odd group of frogs,” said Lucinda Lawson, a conservation biologist and assistant professor of research at the University of Cincinnati.
“The male frogs don’t call like most other frogs do. We think they may use the spine as something like Braille for species recognition,” Lawson said. “Without a call, they need some other way to recognize each other.”
This group of frogs has only a few species, found in small populations that make them rare and at risk of extinction. Finding a new member of this group is a major win for conservation, Lawson said.
The discovery was described in the journal PLOS ONE.
Lawson in 2019 led an international team on an amphibian search of the Ukaguru Mountains, where scientists have conducted at least seven previous surveys. They were hoping to find the beautiful tree toad, Churamiti maridadi, an amphibian that has only been observed twice in the wild in this same forest and is feared extinct.
“Our hopes were not very high. We knew the odds were stacked against us,” said study co-author H. Christoph Liedtke, a postdoctoral researcher with the Spanish National Research Council.
Researchers scoured undisturbed streambanks both day and night, documenting their search with handheld global-positioning satellite receivers. They looked under logs and in tree holes in an area of forest used by beekeepers, poachers and small-scale loggers.
They also set pitfall traps made of plastic buckets buried at ground level to catch amphibians that hide under the leaf litter. Researchers consulted with local foresters and distributed photos of the toad to nearby residents hoping someone — anyone — might have seen it.
While researchers never found the toad, they came across a locally abundant population of reed frogs unknown to science.
“Time spent looking for the beautiful tree toad yielded unexpected results. It was a fantastic finding that made the effort well worth it,” Liedtke said.
The newly discovered reed frog joins a family of nearly 200 species in the genus Hyperolius. Lawson said they immediately recognized they had found something special.
“With any Hyperolius, I can probably tell by looking at it whether it’s new or potentially new,” Lawson said.
“Immediately it was clear that it was a spiny-throated reed frog. But this one was a golden, greenish brown instead of the green color found in the other species,” Lawson said. “Sometimes color variation doesn’t mean anything, but it might here.”
A combination of genetic and genomic analyses confirmed the frog was distinct from other members of Hyperolius. Researchers also identified its closest evolutionary relation, Hyperolius ruvuensis, another species that is critically endangered and is likely extinct.
Measurements found that the frog has unique body proportions, with smaller eyes in relation to its head than other spiny-throated reed frogs.
Describing a species is the first step toward protecting it, particularly in increasingly fragmented forests like those in the Ukaguru Mountains, Lawson said.
According to the study, the newly discovered frog could be of high conservation concern.
“The Mamiwa-Kisara North Forest Reserve is a T-shaped remnant forest,” Lawson said. “It has a lot of edge effects from people cutting firewood. There are all sorts of pressures on this forest. It’s easy to cross the whole thing in just a few hours of hiking.”
Knowing how many species exist and where is critical to conservation, Liedtke said.
“The Ukaguru Mountains are part of the greater Eastern Arc Rift, a fascinating cradle of biodiversity, with many species endemic to single mountain blocks,” Liedtke said. “The fast population growth in Tanzania means that the mountain forest habitats are under growing threats from people.”
Amphibians are especially susceptible to human impacts. Since they absorb chemicals through their skin, they are vulnerable to toxins or changes in water acidity.
“If a bird’s habitat is destroyed, they sometimes can fly to a new forest. But that’s hard for amphibians,” Lawson said.
Having a diverse number of species is important to maintain healthy ecosystems, Lawson said.
“We think about this question a lot: why does one species matter?” Lawson said.
Frogs are part of the food chain. They eat insects and, in turn, are eaten by other animals.
“If this one species goes extinct, nothing much happens. We just lose one more strand in the fabric of the ecosystem,” Lawson said. “But if you keep pulling out strands, the ecosystem becomes destabilized and the fabric unravels.”
Co-author Simon Loader, curator of vertebrates at London’s Natural History Museum, said he was thrilled to help describe a new species. The discovery shows how much more there is to learn about diversity-rich parts of the world.
“We still have a long way to go before understanding what species are there and where they can be found,” he said. “This is particularly the case for the biodiverse-rich submontane forests of Tanzania”
Also contributing to the study were UC biology graduate Erin Siemer and doctoral student John Lyakurwa of the University of Dar es Salaam in Tanzania.
Diversification of spiny-throated reed frogs (Anura: Hyperoliidae) with the description of a new, range-restricted species from the Ukaguru Mountains, Tanzania
A newfound ‘croakless’ frog may
communicate via touch
The animal might use spines on its throat to recognize potential mates instead of calls
Rather than croaking, a newfound frog (Hyperolius ukaguruensis) might use the spines on its throat to communicate via sense of touch.
A newfound species of frog doesn’t ribbit. In fact, it doesn’t make any sound at all.
Many frogs have unusual characteristics, from turning translucent to being clumsy jumpers (SN: 12/22/22; 6/15/22). The recently discovered amphibian lacks a voice. It joins a group of seven other voiceless frog species called spiny-throated reed frogs that reside in East Africa.
Instead of croaking, the spines on male frogs’ throats might help their female counterparts recognize potential mates via touch, sort of like braille, says conservation biologist Lucinda Lawson of the University of Cincinnati.
Lawson and colleagues spotted the little frog, only about 25 millimeters long, in 2019 while surveying wildlife in Tanzania’s Ukaguru Mountains. The team immediately recognized the animal, now named Hyperolius ukaguruensis, as a spiny-throated reed frog. But something seemed off.
“It [was] the wrong color,” Lawson says. Most frogs from this group are green and silver, but this one was gold and brown. Some quick measurements to check if the peculiar frog simply had trivial color variations or if it could be a new species revealed that its eyes were smaller than other spiny-throated reed frogs. The researchers agreed: “Let’s do some genetics,” Lawson says.
They ran DNA tests on two frogs that looked like they belonged to the suspected new species, as well as 10 individuals belonging to known spiny-throated species. Comparing the golden frogs’ genetic makeup with that of the others revealed the oddballs were genetically distinct, Lawson and colleagues report February 2 in PLOS ONE.
The golden-hued Hyperolius ukaguruensis stands out from its fellow spiny-throated reed frogs, which also lack a voice but are typically green.
Each frog species in this voiceless group — including H. ukaguruensis — lives in its own isolated domain of forest. All seven of the previously known species are endangered or vulnerable. This seclusion makes it vital to distinguish species and get them added to the conservation priority list, Lawson says. Then, governments and organizations can begin protecting the region that the new, potentially endangered animal calls home.
First assessment of livestock predation risk from brown bears in Romania
Brown bear management and conservation are the core of heated debates in Romania. As the country harboring the largest population of brown bears in Europe, coexistence between bears and people has always been at the forefront of brown bear management and conservation. Livestock predation is the main source of conflict in rural communities in the Romanian Carpathians, as domestic animals are the foundation, and often the main source of income for local economies. While this topic is prominent in the ongoing discourse around brown bear management in Romania, the drivers determining predation risk to livestock have not been well understood.
Assessing livestock predation risk and mapping risk – and potential human-bear conflict areas – is what a team of researchers from the University of Bucharest, Ohio University and several management agencies and environmental NGO’s, led by Dr. Mihai Pop (University of Bucharest) and Marissa Dyck (PhD student at Ohio University, Conservation Biology Lab), sought to investigate and have recently published in open-access journal Conservation Science and Practice. This study is the culmination of a large collaborative data collection effort spearheaded by three local Environmental Protection Agencies and funded by the LIFE NATURE project LIFEURSUS. For nine years, between 2008 and 2016, teams of wildlife managers, veterinarians and local authorities responded to bear livestock predation incidents, documenting the type of livestock, number of animals killed, location of events and other relevant data.
“Overall, we found that three different types of livestock: cows, sheep and other animals, such as pigs, chickens or horses, differed in their exposure and risk to bear predation, and that predation risk was driven by both environmental and social factors, such as grazing regime," said Dyck. “In particular, the risk of predation for cows is higher near villages and forest edges, as well as in areas with traditional land use, such as pastures intermixed with small forest patches, or orchards. Sheep had high risk of predation from bears near forest edges and in areas with large continuous pastures, such as those situated at higher elevations."
The researchers found that, in general, livestock damage was more prevalent near villages, suggesting that bears make use of food resources associated with human habitation, visiting dumps, but also gardens and orchards. In addition, there were no trends through time in the number or type of livestock predation events throughout the study period.
The authors believe that the differences between sheep and cows predation risk is likely due to their different grazing regimes. Cows are often less well guarded, even when grazed away from settlements, with minimal human supervision. Thus, grazing cows near villages and farther from forest edges would lessen the risk of predation. Traditional sheep grazing management involves migration or short transhumance between higher altitude meadows during summer and lowland villages during winter. This makes sheep more prone to predation near forest edges in remote areas. In contrast to cows, sheep are well guarded when in remote areas, with constant supervision from sheepherders and guard dogs, who sometimes are present during nighttime in the same corral with sheep and guard dogs.
One important finding of this study was that the brown bear abundance was positively associated with predation risk for all livestock species.
"This finding was expected, as many studies of bear predation on livestock have shown a similar pattern. However, it is important to note that the bear abundances used in this study were not validated scientifically and may not reflect the actual abundance; they are only useful in relative terms, for example if one game management unit had double the abundance of a neighboring unit," Pop added.
In a study published in 2016, Pop and colleagues found that the official abundance estimates were not reliable and frequently overestimated the number of bears in two of the counties used in the current study. Therefore, they argue that while bear abundance is indeed influencing predation risk for livestock, this study cannot provide definite cutoffs or thresholds of bear abundance that would eliminate risk. Two other factors add complexity to this issue. First, areas with highest brown bear densities correspond to high food subsidies, either intentional via supplemental feeding of wildlife by managers or unintentional via suboptimal trash management. Second, some predation instances analyzed here were likely done by “repeat offenders,” bears which are habituated to humans, frequently come near villages and predate repeatedly on livestock. This is important from a bear population management perspective. After the 2016 ban on trophy hunting, a management system that can only use lethal methods in cases of conflictual bears has been implemented. Therefore, removing animals that repeatedly prey on livestock could be a feasible strategy to alleviate and minimize livestock losses.
Dr. Cristian Ioja, professor at the University of Bucharest, Department of Geography and co-author on the study, added that mapping the livestock predation risk at the landscape level provides a critical piece of information towards human-bear coexistence.
"Highlighting high risk areas informs both local communities and management agencies on targeting management solutions," Ioja said. "These could involve shifting grazing patterns away from high-risk areas, improved livestock defense or decreasing food subsidies that attract bears close to human habitation, both via improved trash management or less supplemental feeding of wildlife.”
Overall, this study sets the baseline for understanding the landscape of human-bear conflict and opens many other questions about human-bear coexistence. The authors plan to collate data on livestock depredation after the hunting ban (2017 onwards) to understand potential changes in the spatial patterns and frequency of depredation events. In addition, the authors plan to collaborate with social scientists to understand the attitudes of local communities affected by livestock depredation towards brown bears and the best solutions to alleviate conflict.
JOURNAL
Conservation Science and Practice
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
Predictors of brown bear predation events on livestock in the Romanian Carpathians
How species partnerships evolve
Biologists from the School of Arts & Sciences explored how symbiotic relationships between species evolve to become specific or general, cooperative or antagonistic.
Symbiotic relationships are everywhere in nature. In the soil, for example, mycorrhizal fungi enhance water and nutrient absorption for plants while feeding on sugars their roots release. In another classic mutualism, ants find food and shelter in specialized structures that acacia trees grow; the insects, in turn, defend the trees from being eaten by other hungry critters.
Yet not all mutualistic relationships are created equal. Some interactions are highly specific—one host may pair off with only one other species—while others are general and flexible. Specific relationships may lend advantages, allowing the two species to co-evolve to reap even more benefits from one another. But specificity also comes with opportunity costs. And mutualisms aren’t all give-give-give. One “partner” could wind up exploiting the other, taking more than it offers in return.
In the journal Evolution, researchers from the University of Pennsylvania consider the evolutionary dynamics that govern how these two forms of specialization—cooperative or antagonistic—as well as generalist symbioses arise, persist, or wane in a model framework using game theory.
“Each interaction has very different dynamics,” says Erol Akçay, an associate professor of biology at Penn and senior author on the paper. “Generalists may evolve to work better with more partners, specialists may be specializing to be more cooperative, and other specialists may be specializing to exploit better. Ours is the first study that gets at that dialectical nature of specialization, not just looking at specialization versus generalization.”
The investigation arose when Chris Carlson, now a graduate student at the University of Toronto, was an undergraduate at Penn working in marine biologist Katie Barott’s laboratory. The Barott lab uses sea anemones as a model organism for understanding coral biology. Both corals and anemones live in partnership with symbiotic algae, in which the algae provide the corals with food and consume their waste products.
Occasionally, Carlson’s experiments, in which he would “infect” anemones with algae, would “hit a hiccup.”
“Some host corals don’t play ball with certain algae,” Carlson says. “Some hosts are generalists that associate with a broad set of partners, and others are specialists that only associate with one partner.”
The question of why some symbioses are more specific and others are more general has generated much investigation among scientists, but Carlson became interested in a more nuanced aspect of these mutualisms.
“I was interested in understanding why this variation in generalism and specialism might persist in real world ecosystems,” says Carlson, including both more cooperative and more exploitative specialist mutualisms. “For the anemone, all it cares about is its own fitness. If it evolves to get better at interacting with its partnering algae, it may not be acting in its partner’s best interest.”
To investigate this dynamic, Carlson began meeting with Akçay and then-postdoc Bryce Morsky, now a faculty member at Florida State University, to approach the question from a theoretical point of view. The three worked together to develop a model that imagines the interactions of designated “hosts” with either general or specialized preferences and “symbionts” that provide and receive different benefits and costs from their interactions with various hosts.
Overall, the team found that a cooperative partnering strategy, in which both partners reap increasing benefits from their relationship, could persist in populations with one specialized host and a corresponding specialized symbiont. Depending on the benefits, or payoffs involved, a generalist partnering strategy could also persist in this scenario.
Yet when the researchers’ model involved partnerships that were more antagonistic—the host deriving increasing benefits while the symbiont reaped less—a more dynamic outcome arose, with different hosts and symbionts coming to rise and fall in the population over time. Generalist hosts driven to extinction if the payoff for being a generalist was lower than that of being a specialist. These cycles also created peril for both the symbionts and hosts. “We did see these oscillations in our model that, in the real world, could mean a population crashes,” Morsky says.
The researchers then applied a spatial layer to their models, reflecting the reality that mutualistic relationships require that the two species involved encounter one another in space.
“Neighbors are going to be more likely to interact with neighbors, so who your neighbor is and how they interact can affect the outcome,” Morsky says.
When the model allowed certain interactions to take place in defined areas, they found that cooperative specialists could develop “patches” of dominance if they could move over short distances. And if the payoff for being a generalist was high enough, generalists could persist around the periphery of these patches. If, however, hosts and symbionts could move over greater distances, just one host-symbiont pair could completely dominate a space.
“Let’s say you have a coral reef with different types of coral and different types of algae,” Akçay says. “If a host is a cooperative specialist, and the symbiont it specializes on gets fixed, the host does better, and therefore those hosts may expand. That creates specific spatial patterns that we were able to track.”
An overall takeaway, the researchers say, is that cooperative specialization appears to be a valuable strategy but doesn’t come without risks. A host’s cooperating partner could go extinct, for example, leaving the host in the lurch without a symbiont.
By adding complexity to the “generalist versus specialist” dichotomy, the researchers hope their work lends insight into the variety of patterns of mutualisms that exists in nature, which contribute to the biodiversity we see in the world around us.
“When people discuss specialization, this dualism is always in the background,” Akçay says. “This work helps bring it out and clarifies the tensions that exist between mutualisms.”
Erol Akçay is an associate professor in the University of Pennsylvania School of Arts & Sciences’ Department of Biology.
Chris Carlson graduated from Penn in 2020 and is now a graduate student at the University of Toronto.
Bryce Morsky was a postdoc at Penn and is now an assistant professor at Florida State University.
