Thursday, May 22, 2025

Diversity is key to ecosystem stability

University of Helsinki

In a collaborative study led by researchers at the University of Helsinki, analysis of 900 species over a 20-year period showed that biodiversity enhances ecosystem stability and helps safeguard natural communities in a changing environment.

Alongside climate change, biodiversity loss caused by human activity is one of the greatest environmental challenges of our time. A study conducted at the Research Centre for Ecological Change, University of Helsinki investigated how the diversity of natural communities affects their stability amid rapid environmental change.

The results of the study show that diverse natural communities are more stable over time than those with fewer species. This is due to the fact that different species respond differently to environmental change – while some species suffer, others can continue functioning and help maintain the stability of the community as a whole. The researchers also observed that the mechanisms associated with stability vary between taxonomic groups: for some, stability is mainly based on the number of species, while the key factor for others is the functional composition of the community and the way in which species traits supplement each other.

The study was based on an exceptionally comprehensive dataset covering the distributions of 900 species—including birds, butterflies and moths, small and large mammals, and freshwater phytoplankton—in Finland over a 20-year period.

The researchers also demonstrated that so-called functional diversity is a key factor in stabilising natural communities. For example, the functional diversity of a community composed of strictly insectivore birds is narrower than that of a community comprising birds that eat insects, berries and fish. The greatest threat is faced by communities whose species richness and functional diversity are both narrow – the number of species is low, and the species are very alike. In such cases, most of the species in the community are sensitive to the same environmental changes, making it more vulnerable to changes for example in key food resources or abiotic conditions.§

“The findings help us understand mechanisms through which diversity boosts the stability and constancy of natural communities,” says Dr. Tuuli Rissanen, one of the first authors of the study from the University of Helsinki’s Faculty of Biological and Environmental Sciences. “They also help us identify communities that are particularly sensitive to environmental change, allowing us to target conservation measures where they are most effective in curbing biodiversity loss and safeguarding ecosystem services,” adds Dr. Arthur Rodrigues, also a first author of the study.

“For our research, it’s invaluable to have nationwide datasets that include observations on hundreds of species collected over several decades by both professionals and dedicated volunteers. These long-term, large-scale data allow us to uncover ecological processes that would remain hidden if we focused only on individual species or short time series,” adds Professor Anna-Liisa Laine, Director of the Research Centre for Ecological Change.

FACT BOX

Biodiversity and natural capital
The role of biodiversity in maintaining ecosystem stability is a classic hypothesis in ecology, and a key assumption at the core of the natural capital concept. The concept sees diversity as capital that maintains ecosystem services, thus laying the foundation for human wellbeing and economy. In this study, the validity of the hypothesis was investigated in natural populations of hundreds of species, using the unique Finnish longitudinal datasets. The findings confirm the validity of this principle broadly in nature.

Functional diversity
Functional diversity is a key factor stabilising natural communities. The functional traits of species refer to their physical appearance, or morphology, physiology, behaviour, growth, reproduction, survival and resource use. Functional diversity measures the diversity of species’ functional traits.

Journal

Ecology Letters

DOI

10.1111/ele.70003

Subject of Research

Animals

Article Title

Cross-Taxa Analysis of Long-Term Data Reveals a Positive Biodiversity-Stability Relationship With Taxon-Specific Mechanistic Underpinning

How modern dog ownership has redefined family and parenting

Birth rates are declining worldwide, while dog parenting practices are gaining popularity. What does this growing “furry children” trend reveal about our societies?

Eötvös Loránd University

Birth rates are declining worldwide, while dog parenting practices are gaining popularity. What does this growing “furry children” trend reveal about our societies? Researchers from Eötvös Loránd University suggest that, while dogs do not actually replace children, they may, in some cases, offer an opportunity to fulfil a nurturing drive similar to parenting, but with fewer demands than raising biological offspring. Their review, published in European Psychologist, also examines how the shifting roles of dogs within modern family structures are influenced by individual circumstances, but also by cultural norms.

Many wealthy and developed countries—including much of Europe, North America, and East Asia—are now experiencing sub-replacement fertility, meaning people are having fewer children than needed to maintain the population over time. In contrast, dog ownership has gained popularity over the last decades. In most European countries, a quarter to half of households own at least one dog, often regarded as a family member or even a furry baby.

Does it mean that people choose to have dogs in place of children?

Researchers from the Department of Ethology at ELTE Eötvös Loránd University conducted a comprehensive review of the literature in an attempt to answer this question. One of their core ideas posits that, for some people, dogs may represent a fulfilling compromise, satisfying a genetically-embedded drive to nurture and form social bonds without investing the substantial resources necessary to raise biological offspring. In other words, dogs kept as pets offer the opportunity to form a close emotional connection with a dependent being, providing positive emotions, social support, and even a sense of purpose – outcomes that, to some extent, resemble those experienced by parents – while being easier to control and care for than a child.

But why would dogs be good candidates to fill child-like roles in the lives of humans?

First, their cognitive abilities and adaptability to human communication enable them to exhibit a wide range of social behaviours, often comparable to those of pre-verbal children. Additionally, some dogs, particularly those exhibiting extreme infantile traits (e.g., small brachycephalic breeds such as pugs and French bulldogs), may look as helpless, harmless and innocent as small children. Another parallel between companion dogs and young children is their evident dependency on their caregivers. Most dogs kept in human families cannot decide what to eat, where and when to go for a walk, or with whom to interact. For this reason, owners are responsible for providing appropriate care to them, and in many countries, legal frameworks have been created to protect the rights of both animals and children.

« Despite the high dependency and attachment of dogs to their caregivers, in the eyes of many, commitments coming with dog ownership remain less burdensome than child parenting », explains Laura Gillet, PhD student at the Department of Ethology. « Among many factors, the relatively short lifespan of dogs might contribute to it, as most people expect to outlive their dog, but not their child ». Moreover, previous studies have shown that in many Western, traditionally Christian-influenced societies, animal lives remain less valued than human lives. Therefore, not only individual decisions, but also sociocultural context are crucial to understanding how and why people develop certain types of relationships with their animals.

« We would like to point out that, contrary to popular belief, only a small minority of dog owners actually treat their pets like human children. In most cases, dog parents choose dogs precisely because they are not like children, and they acknowledge their species-specific needs », adds Eniko Kubinyi, head of the MTA-ELTE ‘Momentum’ Companion Animals Research Group, senior author of the review. Still, a dog’s wants and needs don’t always align with what their owners expect or desire. This is a crucial point when it comes to animal welfare. Treating dogs as child substitutes and seeking extreme infantile traits in them raises several ethical concerns, such as the mass breeding of certain unhealthy breeds or overprotective caring behaviours that may lead to emotional and behavioural problems in the dog.

In conclusion, dog keeping practices, including dog parenting, take many forms, all of which depend on a given sociocultural context and individual circumstances, and can change throughout the lifespan of a person. For instance, the dog can serve as a “pre-child” of a young, childless couple, and later become a furry sibling to their firstborn. The authors of the study also propose alternative ways of thinking about the dog-human bond, blending the characteristics of different human relationships – not only the child-parent relationship, but also friendship and partnership - resulting in a unique bond with its own dynamics. Moreover, the

shifting roles that companion animals, including dogs, play in human lives are redefining the concept of family and definitely call into question our modern lifestyles, marked by increasing loneliness and a weakening of social and community ties.

The authors are currently running a new study to deepen the understanding of the dog-human relationship. Dog owners across the world are invited to answer the following questionnaire: https://tally.so/r/nPXKPb

Funding: This study was supported by the Hungarian Academy of Sciences via a grant to the MTA-ELTE 'Lendület/Momentum' Companion Animal Research Group (grant no. PH1404/21), the National Brain Programme 3.0 (NAP2022-I-3/2022), and the DKOP-23 Doctoral Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund.

Article original: Gillet, L., Kubinyi, E. (2025). Redefining Parenting and Family - The Child-Like Role of Dogs in Western Societies. European Psychologist. DOI: 10.1027/1016-9040/a000552

Journal

European Psychologist

DOI

10.1027/1016-9040/a000552

Article Title

Redefining Parenting and Family - The Child-Like Role of Dogs in Western Societies.

Article Publication Date

22-May-2025

How cholera bacteria outsmart viruses

Ecole Polytechnique Fédérale de Lausanne

Vibrio cholerae bacteria, photo taken with a Scanning Electron Microscope. — image:
*Vibrio cholerae* bacteria, photo taken with a Scanning Electron Microscope.
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Credit: Graham Knott & Melanie Blokesch (EPFL)

When we think of cholera, most of us picture contaminated water and tragic outbreaks in vulnerable regions. But behind the scenes, cholera bacteria are locked in a fierce, microscopic war—one that could shape the course of pandemics.

Cholera bacteria aren’t just battling antibiotics and public health measures—they are also constantly under attack from bacteriophages (phages), viruses that infect and kill bacteria. These viruses don’t just influence individual infections; they can make or break entire epidemics. In fact, certain bacteriophages are thought to limit the size and duration of cholera outbreaks by killing off Vibrio cholerae, the bacterium behind the disease.

Since the 1960s, the ongoing 7th cholera pandemic has been driven by what are known as “seventh pandemic El Tor” (7PET) strains of V. cholerae, which have spread globally in successive waves. In this evolutionary arms race, bacteria have adapted to fight back, developing defense mechanisms against these phages. For example, many bacterial strains carry mobile genetic elements that arm them with anti-viral tools. So why are certain cholera strains so successful at evading phage attacks? Could this either enable or enhance the pathogen’s devastating effect on human populations?

One event stands out. In the early 1990s, a cholera epidemic swept through Peru and much of Latin America, infecting over 1 million people and causing thousands of deaths. The strains responsible belonged to the West African South American (WASA) lineage of V. cholerae. Why these WASA strains caused such a large outbreak in Latin America is still not fully understood.

New research by the group of Melanie Blokesch at EPFL’s Global Health Institute has now uncovered one secret behind these strains. The study, published in Nature Microbiology, shows that the WASA lineage acquired multiple distinct bacterial immune systems that have protected it from diverse types of phages. And this defense may have contributed to the massive scale of the Latin American epidemic.

The researchers looked at Peruvian cholera strains from the 1990s, testing their resistance against key phages, especially ICP1—a dominant virus that has been extensively studied in the cholera endemic area of Bangladesh where it is thought to contribute to restricting cholera outbreaks. Surprisingly, the Peruvian strains were immune to ICP1, while other strains representative of the 7th pandemic weren’t.

By deleting specific sections of the cholera strain’s DNA and inserting these genes into other bacterial strains to test their function, the team identified two major defense regions on the WASA strain’s genome, namely within the so-called WASA-1 prophage and the genomic island known as Vibrio seventh pandemic island II (VSP-II). These genomic regions encode specialized anti-phage systems that work together to create a bacterial immune system capable of defending against phage infections.

One such system, WonAB, triggers an “abortive infection” response that kills infected cells before phages can reproduce, sacrificing a few bacteria to save the larger population. This strategy is different to classical bacterial immune systems such as restriction-modification systems that degrade the phage DNA as it enters the cells. “Instead, it stops the phage from replicating but only after it has already hijacked the cholera bacterium's cellular machinery, effectively locking the infected bacteria in a standoff—but at least the phage doesn’t spread,” says David Adams, the study’s lead author.

Two further systems, GrwAB and VcSduA, contribute distinct protective functions: GrwAB targets phages with chemically modified DNA—a strategy employed by phages to camouflage their genomes and evade other bacterial immune systems. VcSduA on the other hand acts against different families of viruses including another common “vibriophage”, offering layered protection that broadens the bacterial population’s resistance spectrum.

Essentially, the WASA lineage of cholera bacteria harbors an expanded arsenal of anti-phage defense systems, which allows it to counteract a broad range of bacteriophages in addition to protection from its major predatory phage ICP1.

Understanding how epidemic bacteria resist phage predation is crucial, especially as interest in phage therapy—the use of viruses to treat bacterial infections— has re-emerged as an alternative to antibiotic treatment. If bacteria like V. cholerae can acquire increased transmission potential by obtaining viral defenses, this can reshape how we approach cholera control, monitoring, and treatment. It also underscores the importance of considering phage-bacteria dynamics when studying and managing infectious disease outbreaks.

Reference

David W. Adams, Milena Jaskólska, Alexandre Lemopoulos, Sandrine Stutzmann, Laurie Righi, Loriane Bader, Melanie Blokesch. West African South American pandemic Vibrio cholerae encodes multiple distinct phage defence systems. Nature Microbiology, 22 May 2025. DOI: 10.1038/s41564-025-02004-9

Journal

Nature Microbiology

DOI

10.1038/s41564-025-02004-9

Article Title

West African South American pandemic Vibrio cholerae encodes multiple distinct phage defence systems.

Article Publication Date

22-May-2025

LA REVUE GAUCHE - Left Comment: Search results for bacteriophage

Spatiotemporal evolution of wildfire activity during the Paleocene-Eocene Thermal Maximum in China

Science China Press

The BC concentrations, δ13C values, and sequences of paleoclimatic proxies for the Beigou section of the Nanyang Basin during the PETM. — image:
(a) δ13CTOC record. (b) δ13CBC record. (c) BC/TOC ratio. (d) Carbonate content. (e) Dolomite/carbonate ratio. (f) Molar Sr/Ca ratios of authigenic carbonates. (g) Molar Mg/Ca ratios of authigenic carbonates. (h) Kaolinite/smectite ratio. (i) Temperature estimates from branched glycerol dialkyl glycerol tetraethers. The gray shadow represents the PETM event.
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Credit: ©Science China Press

This study is led by Wang Xueting, Dr. Wang Xu, and Dr. Chen Zuoling from the State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences. The researchers analyzed black carbon concentration and carbon isotope (δ13C) in sediments from the Beigou section of the Nanyang Basin and the Xilutian section of the Fushun Basin to reconstruct the regional wildfires. To further explore the spatiotemporal evolution and driving mechanisms of wildfires, the researchers integrated paleofire studies from different regions of the Northern Hemisphere during the PETM. The study revealed a " low wildfire activity " in most regions of the Northern Hemisphere during the PETM period.

Specifically, the variation in the BC/TOC (black carbon/ total organic carbon) ratio indicates the frequency and intensity of wildfire activity in both the Nanyang Basin (arid/semi-arid zone) and the Fushun Basin (humid zone) during the PETM. The result shows a sharp decrease in wildfire activity at the onset of the carbon isotope excursion (CIE), which remained low throughout the CIE, except for a brief increase in the Nanyang Basin during the mid-CIE. Subsequently, the wildfire activity gradually intensified during the CIE recovery phase, ultimately returning to pre-PETM levels (Figure 1c and Figure 2c). During the PETM, the global climate was extremely warm and wet. The pollen assemblages in most areas of the Northern Hemisphere indicate a succession of vegetation types during this period, with an increase in angiosperms and wetland plants and a decrease in gymnosperms and ferns. Therefore, they suggest that the low diversity of fire-prone vegetation in most regions of the Northern Hemisphere during the PETM was likely caused by changes in climate and vegetation. During the PETM, excessive rainfall would have increased the moisture content of combustible materials, thereby suppressing the occurrence of wildfires. The warm and humid climate would have promoted vegetation growth and the succession of vegetation types, inhibiting the spatial continuity of combustible materials, and ultimately reducing the occurrence and spread of wildfires. Furthermore, the climate during the PETM was marked by indistinct seasonality, with no obvious dry season, or at the most, a shorter one, conditions unfavorable for the occurrence of wildfires.

Additionally, the results reveal that a significant decrease in BC concentration at the onset of the CIE, indicating reduced burial of inert carbon, with more carbon being stored in the biological-atmospheric surface system. During the CIE recovery phase, the BC concentration increased, indicating an increase in the burial of inert carbon and a shift in carbon from the short-term biological-atmospheric carbon cycle to the long-term geological carbon cycle. This carbon sink transformation process may have contributed to light carbon consumption during the PETM recovery phase, acting as a negative feedback mechanism and impacting regional carbon reservoirs and the global carbon cycle.

See the article:

Wang X T, Chen Z, Cui L, Wang X. 2025. Spatiotemporal evolution of wildfire activity during the Paleocene-Eocene Thermal Maximum in China. Science China Earth Sciences, 68(2): 509–522, https://doi.org/10.1007/s11430-024-1472-5

Journal

Science China Earth Sciences

DOI

10.1007/s11430-024-1472-5

High-performance steel that could disrupt high end manufacturing

Songshan Lake Materials Laboratory

Steel remains the backbone of modern infrastructure, from skyscrapers to cars, but pushing its mechanical limits has long meant choosing between strength and ductility. Advanced high-strength steels (AHSS), especially third-generation variants, have made significant strides by introducing complex alloying and multi-phase microstructures. However, many rely on intricate processing routes or costly alloying elements. The challenge remains: how to create steels that are not only ultra-strong but also formable and cost-effective.
One promising approach is the TRIP effect, where metastable austenite transforms into martensite under stress, enhancing ductility and strength. This effect is enabled by carbon partitioning, which produces a three-phase structure of retained austenite, existing martensite/ferrite, and newly formed martensite. Separately, recent progress has allowed the formation of L1₂-type nanoprecipitates in both ferrite and austenite. The natural next step is to explore whether combining TRIP behavior with L1₂ precipitation can synergistically push the boundaries of steel performance.

The Solution

A group of researchers from Zhejiang University developed a new Fe-Ni-Al-Ti-C steel alloy based on three key strategies: adding carbon stabilizes austenite, enabling the TRIP effect for enhanced ductility; during aging, carbon partitions efficiently while Fe, Ni, Al, and Ti remain immobile, allowing formation of metastable austenite and strengthening L1₂ nanoprecipitates; and carefully tailored heat treatments align with TTT behavior to optimize phase balance. This synergy achieves tensile strengths of 1.2–1.8 GPa and uniform elongation of 10–30%

The Future

“High strength and high ductility typically don’t coexist. This steel breaks that rule,” says Dr. Qingqing Ding, the leading author of the paper “It delivers top-tier performance without the complexity or cost of more expensive alloying elements.” The synergy amongst carbon partitioning, nanoscale L12-precitiapates, and TRIP effects is shown to be an effective approach in achieving a promising synergy of strength and ductility in an uncharted territory on the strength-ductility map. Consequently, this work points out guidelines for future alloy design (i.e., by tuning or adding various elemental compositions to manipulate TRIP effects and precipitation strengthening together) and provides a critical factor that can be integrated with other approaches such as heterostructure induced strengthening.
This research is particularly timely as manufacturers worldwide face rising pressure to improve material efficiency, reduce weight, and increase sustainability. Unlike traditional complex processing routes, this alloy uses a more straightforward heat treatment process, offering both economic and energy advantages.

The Impact

This alloy opens new doors for lightweight design in electric vehicles, structural components in infrastructure, and even defence applications where performance under extreme conditions is non-negotiable.
The research has been recently published in the online edition of Materials Futures, an international scientific journal.

Reference:
Qingqing Ding, Zhongtian Wu, Yanfei Gao, Yuefei Zhang, Xiao Wei, Ze Zhang, Hongbin Bei. Excellent mechanical properties from the synergy of carbon partitioning, L12-nano-precipitation and TRIP effects in Fe-Ni-Al-Ti-C steel[J]. Materials Futures. DOI: 10.1088/2752-5724/adda68

Journal

Materials Futures

DOI

10.1088/2752-5724/adda68

LA REVUE GAUCHE - Left Comment

Thursday, May 22, 2025

Diversity is key to ecosystem stability

Diversity is key to ecosystem stability.

Journal

DOI

Subject of Research

Article Title

How modern dog ownership has redefined family and parenting

Journal

DOI

Article Title

Article Publication Date

How cholera bacteria outsmart viruses

Journal

DOI

Article Title

Article Publication Date

Spatiotemporal evolution of wildfire activity during the Paleocene-Eocene Thermal Maximum in China

Journal

DOI

High-performance steel that could disrupt high end manufacturing

Journal

DOI

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