New global study reveals link between local-scale species changes and global extinction risk

University of St. Andrews

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An assembly of tropical fish 

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Credit: University of St Andrews

New research from the University of St Andrews has shown that higher extinction risk is associated with higher frequency of decreasing local prevalence of species, in an analysis of one of the most comprehensive long-term databases ever created, BioTIME – a major tool to study biodiversity change also developed at the University of St Andrews. 

Published today (23 June) in Nature Communications, researchers from the School of Biology alongside a team of international partners, analysed over 60 000 populations of 2362 species across 978 marine and terrestrial assemblages. These populations have been sampled comprehensively over at least 20 years. 

An assemblage refers to a group of species from the same taxonomic group that co-occur within the same geographic location and time period, such as, a bird or fish assemblage. Analysing assemblage-level data allows us to systematically quantify change over time for many species and populations, and identify which ones might be faring better, i.e. assessing the “winners and losers” amidst ongoing global change. 

The analysis matched each population’s temporal prevalence trend with each species’ extinction risk from the International Union for Conservation of Nature (IUCN) Red List. The picture that emerged was of complex links between the two factors, but a clear signal also emerged that decreasing temporal trends were associated with higher extinction risk compared to the other trends. Overall, fewer than 10% of populations showed either increasing or decreasing prevalence over time 

Joint lead Author, Dr Faye Moyes from the School of Biology at the University of St Andrews, said: “Our results highlight the importance of assemblage level monitoring in conservation strategies and shows the value of long-term time series such as those in BioTIME. “ 

Joint lead Author, Laura Antão, based at the University of Turku in Finland, added “We have assessed for the first time whether there is a consistent signal between population temporal trends and a species extinction risk status using assemblage monitoring data, rather than ‘dedicated’ species-level assessments. Finding a clear signal that decreasing prevalence is usually associated with a higher risk of extinction is a strong indication that we can detect impacts even for species that are not currently classified as at risk”. 

As global environmental change continues to accelerate, extinction risks are rising and  assemblages are being reorganised across taxa, biomes and realms. The team also revealed complex links between local temporal prevalence and extinction risk categories: some populations of threatened species could have stable or increasing trends, while non-threatened species could be decreasing. A better understanding of the processes that underpin such biodiversity changes is crucial for improving predictions and conservation strategies. 

Professor Anne Magurran, a senior author of the study, added: “These temporal trends could serve as early‑warning indicators and help target both new monitoring efforts and conservation actions. For instance, stable populations of at-risk species are of key conservation interest, while declining trends might highlight species that are missing from extinction risk assessments”. 

Professor Maria Dornelas added: “Because the task of assessing biodiversity change is gigantic, and we cannot travel in time to collect more data in the past, we want to use all information available. These two large biodiversity databases have only limited overlap and this study shows us how we can leverage both to expand our understanding of biodiversity change.” 

 

ENDS

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Journal

Nature Communications

DOI

10.1038/s41467-026-74132-7 

Subject of Research

Animals

Article Title

Linking species local trends from assemblage monitoring to global extinction risk

Article Publication Date

23-Jun-2026

 

Rise in colorectal cancer among young adults in Germany as well — but below US levels

German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ)

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Colorectal cancer is generally considered a disease of older adults. However, a new analysis of German cancer registries shows that the number of new colorectal cancer cases among younger adults has risen slightly over the past two decades. Those most affected are people between the ages of 20 and 39. The findings are based on data from ten German cancer registries and cover the period from 2003 to 2023.

“Early-onset” colorectal cancer (EOCRC) refers to cases diagnosed before the age of 50. However, reports of rising colorectal cancer rates among younger people—particularly from the U.S.—prompted scientists at the German state cancer registries to take a closer look at the disease situation in Germany

Marked Increase Among the Youngest

For the current analysis, the experts evaluated more than 28,000 cases of colorectal cancer in people aged 20 to 49. They found that the incidence of colorectal cancer increased among 20- to 29-year-olds as well as among 30- to 39-year-olds. The increase was particularly pronounced in the youngest age group. Among 40- to 49-year-olds, however, the incidence rate remained largely stable overall.

“Our results show that the rise in colorectal cancer among young adults in Germany is real, but—at least so far—it is significantly more moderate than in the U.S.,” says Volker Arndt of the German Cancer Research Center (DKFZ) and the Baden-Württemberg Cancer Registry, one of the study’s two senior authors.

Germany Well Below U.S. Levels

An important part of the study was the comparison with the United States, where the rise in colorectal cancer among younger adults has been the subject of intense debate for years. The researchers show that incidence rates in Germany are significantly lower than in the U.S., both at the beginning of the study period and currently. Furthermore, the increase has been much slower in Germany.

Why Are the Numbers Rising?

The causes have not yet been fully explained. Lifestyle changes, including obesity, lack of physical activity, and dietary habits, are being discussed as possible contributing factors. Changes in gut flora could also play a role.

At the same time, the results suggest that part of the observed increase could be attributed to earlier and improved diagnosis. In particular, there was an increase in tumors with a comparatively favorable prognosis, which are often detected at an early stage.

No Reason to Lower the Screening Age Across the Board

Despite this trend, the authors currently see no sufficient reason to lower the age limit for colorectal cancer screening in the general population to under 50 years. “Colorectal cancer before the age of 50 remains rare overall in Germany,” emphasizes Jacqueline Müller-Nordhorn of the Bavarian Cancer Registry at the Bavarian State Office for Health and Food Safety. “Of the approximately 56,000 new cases of colorectal cancer each year, only about five percent occur in people under 50. Nevertheless, it should be noted that younger people should, of course, seek prompt, individualized medical care if they experience symptoms. The priority is to consistently identify known risk groups—such as people with a family history of the disease—and offer them the recommended screening tests.

The researchers recommend continuing to closely monitor trends in the incidence of the disease. Future studies should focus on clarifying the role that early life lifestyle factors, obesity, the consumption of highly processed foods, antibiotic use, and/or changes in the gut microbiota play in the development of colorectal cancer at a young age.

Sven Voigtländer, Hiltraud Kajüter, Ina Wellmann, Andras Szentkirályi, Bernd Holleczek, Volker Arndt, Jacqueline Müller-Nordhorn, and the ALSTER Working Group: Incidence trends of early-onset colorectal cancer in Germany: A registry-based study from 2003 to 2023

International Journal of Cancer, 2026, DOI: 10.1002/ijc.70600

 

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Journal

International Journal of Cancer

DOI

10.1002/ijc.70600 

 

Shorter strides can be an early warning sign of dementia in senior dogs, just as in people

Cognitive decline in dogs is associated with changes in the front legs’ gait, yielding a new monitoring tool for vets

Frontiers

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The onset of dementia often comes with a change in gait: for example, years before they display any loss in memory, patients may start to walk more slowly with shorter, uneven, and sometimes shuffling steps. These changes are thought to be driven by a deterioration in the function of the brain’s frontal cortex and the cerebellum, which are responsible for planning and monitoring movement.

Now, scientists have found a similar change in dogs with cognitive dysfunction syndrome, also known as canine dementia. Noting such a change in their pet could thus prompt owners to seek veterinary help earlier. The results are published in Frontiers in Veterinary Science.

“Here we show that the length of front leg stride taken by dogs decreases with age, but even more importantly, decreases with a cognitive impairment. In fact, we found that the effect of cognitive decline is larger than the effect of age by itself,” said lead author Dr Natasha J Olby, a professor of veterinary neurology and neurosurgery at North Carolina State University.

Olby and colleagues followed 88 senior and geriatric dogs (females and males, and purebred or mixed breed) as part of the Longitudinal Study of Canine Neuroaging. These had been enrolled in the study upon reaching 75% of the life expectancy for their size and breed, corresponding to 12.7 years old on average.

Longitudinal study of ‘neuroaging’

Dogs visited the laboratory for three days every six months for the remainder of their life. Here, they underwent a comprehensive battery of physical, neurological, physiological, and orthopedic examinations, including tests for cognition, mobility, vision, hearing, and strength. Each time, owners were asked to fill out questionnaires about their companion’s health and behavior, for example the Canine Dementia Scale (CADES) to measure cognitive impairment and the Canine Brief Pain Inventory (CBPI) to assess chronic pain.

A filmed assessment of gait speed and stride length formed an integral part of these visits. Dogs were set up to walk at their own pace along a five-meter-long walkway, while being held on a slack leash by the researchers. No verbal encouragement, treats, or other external motivations were given to them during these trials. Two key measures analyzed were the dogs’ absolute average stride length and their relative average stride length, adjusted for body size.

The relative stride length of the front legs tended to decrease across visits. But more detailed analyses showed that this reduction was not driven to a significant extent by increasing age itself when age and cognition were included in the same statistical model: rather, the relative stride length decreased with worsening CADES scores, indicating that as dogs age, greater cognitive decline results in shorter strides of the front legs.

On average, a 10-point increase in CADES translated into a 1.2% reduction in the relative stride length of the front legs. In contrast, the relative stride length of the hind legs did not significantly change over time, either in association with greater chronological age or worsening cognitive performance.

Stepping down

“It is fascinating to see that cognitive decline affects front legs and hind legs differently. In dogs, the hind legs are important for moving forwards, while the front legs also change direction and initiate braking,” said Olby.

“The cerebral cortex integrates more sensory information into the neuronal circuits which produce steps in the front legs, and so loss of high-level sensorimotor integration affects them differently.”

As expected, the relative stride length of the front legs also decreased with higher CBPI ratings, meaning that chronic pain further worsens the gait.

The authors concluded that front leg stride length is an objective measure of mobility that reflects changes associated with age-related cognitive decline (and, to a lesser degree, chronic pain) in dogs. While other factors like orthopedic and spinal health can influence stride length, it could nevertheless be useful for clinical monitoring.

“If owners notice that their dog's front leg stride is becoming shorter they should visit their vet, for there are possible alternative causes such as arthritic pain or neck issues that can be treated,” recommended Olby. “If a diagnosis of cognitive decline is made, there are likewise several lifestyle interventions than can be made, even if there is currently no cure.”

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Journal

Frontiers in Veterinary Science

DOI

10.3389/fvets.2026.1814017 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Thoracic limb stride length is associated with cognitive impairment in aging dogs

Article Publication Date

25-Jun-2026

 

First-ever protein analysis of Homo naledi fossils finds zero male markers

New analysis of the South African's Rising Star Cave fossils reveals striking genetic singularity, hinting at first known example of a sex-specific burial site from a non-human species

University of the Witwatersrand

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National Geographic Explorer and biological anthropologist Keneiloe Molopyane studying the excavation pit. Molopyane was one of the members of the all-female ‘underground astronauts’ who helped excavate Homo naledi fossils. 

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Credit: Robbie Shone/National Geographic.

An international team of researchers successfully extracted and analysed the first-ever protein fragments from fossil teeth of Homo naledi, an extinct human relative found in the Cradle of Humankind World Heritage Site, South Africa. 

In a study published today in Cell, scientists from the University of Copenhagen, the University of the Witwatersrand, the National Geographic Society’s Rising Star project and 13 collaborating global institutions found no signs of any biological males within the group of Homo naledi remains tested, offering intriguing insights into potential cultural behaviours that may have existed before Homo sapiens.

The analysis examined 23 teeth representing at least 20 Homo naledi individuals. To determine the biological sex of each individual, researchers looked for Amelogenin-Y – a protein that is uniquely coded onto the male Y chromosome – within the tooth enamel. Thorough examination of ancient proteins from the enamel of 23 Homo naledi teethrevealed a complete absence of the marker, indicating a strong likelihood that each individual discovered in the Rising Star Cave system was biologically female. Among hominins, like all other mammals, females typically exhibit two X chromosomes and males carry an X and a Y chromosome. Because only males have a Y chromosome, finding amelogenin-Y tells researchers with certainty that the tooth belonged to a male.

“Unlike those found in other remains like bone fragments, proteins in tooth enamel are preserved because dental enamel – the hardest tissue in the human body – shields proteins from environmental contamination even for millions of years. This makes them ideal carriers of genetic information from deep time,” said South African-born scientist and lead study author Palesa Madupe. Madupe is a molecular scientist who was a postdoctoral researcher at the University of Copenhagen at the time of the study and currently a researcher at Max Planck Institute for Evolutionary Anthropology in Germany. “Our study helps resolve the long-standing mystery of why Homo naledi lacked significant variation; it’s probably because they could have all belonged to one sex.”

As the largest extinct hominin population to ever be examined using ancient protein analysis, the findings raise new questions about the biology, evolution, culture, and potential mortuary practices of Homo naledi. 

When the Wits University team first discovered and excavated the Homo naledi remains in 2013, they noticed something puzzling — the adult fossils found in the Dinaledi Chamber were all very similar. The adult fossils had very little variation in size, shape, and other physical traits. Typically, some variation is expected among hominins, especially among males and females, otherwise known as sexual dimorphism. 

To investigate this anomaly, researchers applied a minimally destructive acid etching technique to carefully extract fragments of ancient proteins — called peptides — from the remains. The peptide samples were then analyzed with a mass spectrometer to identify all of the proteins present in the remains, including amelogenin — a process called paleoproteomic analysis.

“It appears that the most likely explanation for the observed absence of an Amelogenin-Y marker in these individuals is that we are seeing a sex-bias in mortuary practice — a practice until now only observed in contemporary human cultures,” said National Geographic Explorer in Residence and corresponding author of the study Lee Berger, who is still and Honorary Professor at Wits University. “The chance of having sampled twenty individuals and they are all from one sex, is quite literally one in a million.”

First described by Berger and colleagues from the Dinaledi Chamber of the Rising Star cave system, Homo naledi is an extinct hominin species with a combination of human-like and pre-human-like features that lived between 335,000 and 241,000 years ago. Fueled by a curiosity that reaches deep into millennia-old cave systems,  an all-female team of “underground astronauts” in 2013 excavated more than 1,500 fossils and 150 hominin teeth — the largest ever discovered on the continent of Africa — which at the time represented at least 15 individuals. Later, this number grew as more fossils were found by the Rising Star team in this and other areas of the cave. Wits University is the custodian of the Homo naledi fossils.

The results of this study build upon previous insights from the Rising Star team about Homo naledi’s purported behavior. In 2023, the Rising Star team discovered evidence of possible Homo naledi fire, symbols, and burials and in 2025, the team published additional evidence to support their findings of intentional burial practices and the creation of rock engravings.

“There are many past human societies with sex-specific burial practices, but we’ve found very little hard evidence of this from the earliest burial sites of modern humans or Neanderthals,” said John Hawks, a co-author of the paper and member of the Rising Star team. “These remains of Homo naledi are older than any known Neanderthal or modern human burial site, and it’s remarkable to see that they may all be female.” 

Still, the research team acknowledges in this work that there could be another reason for the absence of male markers in the tested Homo naledi remains: the Amelogenin-Y gene may have mutated or have been deleted over time. 

“While the deletion of the entire AMELY gene has already been observed in extant male humans and even in the DNA of a Neanderthal male, it’s very unlikely that this would be the case among even half of the 20 individuals we studied or for an entire population,” explained Enrico Cappellini, professor of paleoproteomics at the Globe Institute, University of Copenhagen, where the analytical work took place, and senior and corresponding author of the study. “Either scenario, namely the absence of H. naledi males in the Rising Star cave system or a systematic deletion of their AMELY gene, is fascinating and would have deep implications for a better understanding of the biology and evolution of this species.”

This finding is particularly significant because Homo naledi is anatomically distinct from modern humans, possessing a brain size only slightly larger than that of a chimpanzee, the authors said. Despite this smaller cranial capacity, a growing body of research suggests the species appears to have engaged in practices once considered uniquely human.

“Seeking to understand where we come from is truly core to the human experience. These new findings are amazing because they’re challenging us to rethink what we thought we knew about our place in human history,” said Ian Miller, chief science and innovation officer at the National Geographic Society. “What I love about the Rising Star team is their restless curiosity. They keep pushing the boundaries of paleoanthropology, and reminding us that the biggest discoveries are still yet to be made.”

The paper, “Proteomic analysis of dental enamel from 20 Homo naledi individuals shows no male markers,” was published June 24, 2026 in the journal Cell. 

Learn more about Berger’s work, the discovery of Homo naledi and the Rising Star program in the new National Geographic Museum of Exploration, opening in Washington D.C. on Friday, June 26, 2026.

  

A fossil mandible of Homo naledi photographed during palaeoanthropological research in the Cradle of Humankind. The specimen forms part of ongoing studies into the anatomy and evolution of the extinct hominin species. Photo by Mathew Berger.

Credit

Mathew Berger

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Journal

Cell

Article Publication Date

24-Jun-2026

 

As Northern Hemisphere temperatures soar, a new app shows players' heat risk for sport

Online sports heat risk app launched internationally to help players check their heat risk across 33 sports, including football

University of Sydney

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The Sports Heat Tool can be used by anyone, anywhere, all over the world to map their heat risk while playing sport in hot weather

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Credit: University of Sydney

As temperatures soar across the Northern Hemisphere, a free tool lets anyone, anywhere check how dangerous the heat really is for their sport and decide whether it is safe to play.

Most people who play sport judge heat by the temperature, or simply by how it feels. But the real danger depends on much more than that. Humidity, the sun, and how hard you are working all affect how much heat your body has to shed, which is why two days at the same temperature can carry very different risks.

The Sports Heat Tool, developed at the University of Sydney, now calculates that risk for anyone, providing sport-specific guidance on heat exposure and a clear answer to a question that millions of people ask each summer: is it too hot to play?

The interactive online tool, downloadable for free from the Apple App Store and online, is designed to help people monitor their heat risk while participating in more than 33 sports and guide safe participation during hot conditions.

From soccer and softball, to canoeing and cycling, users around the world can search their location, check their heat risk, and discover a sport-specific risk profile based on the activity they are doing.

Professor Ollie Jay, Director of the Heat and Health Research Centre at the University of Sydney, who helped develop the tool, said the gap between elite and community sport is stark.

At the elite level there are doctors, cooling stations, and someone whose job it is to call it off when it gets dangerous,” said Professor Jay. 

“A local club has a coach, a hot afternoon, and a judgement call. We have taken the science that the professionals rely on and put it in everyone’s pocket for free. Your body follows the same rules whether you are playing at the FIFA World Cup or a Sunday league.”

How to check your heat risk

Users can enter their location and choose their sport, then the app returns a sport heat-risk score for the hours and days ahead, ranging from low (1.0) through to extreme (5.0), alongside practical steps to bring the risk down.

“It models how a real body exchanges heat with its surroundings, rather than relying on older indices designed decades ago for narrow conditions. It accounts for the temperature, the humidity, the sun and your own exertion, so the risk it shows is the risk you are genuinely facing,” said Dr Federico Tartarini, from the Heat and Health Research Centre and the Sydney School of Architecture, Design and Planning, who co-developed the tool.

A version tailored to children and adolescents, whose bodies manage heat differently to adults will be launched later this year.

 

Lamprey brain atlas uncovers ancestral blueprint of the vertebrate brain

Chinese Academy of Sciences Headquarters

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An adult Far Eastern brook lamprey (Lethenteron reissneri)

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Credit: Image by WU Haixu from Kunming Institute of Zoology

What did the very first complex vertebrate brain look like? To find out, scientists turned to an unlikely time traveler: the lamprey, a jawless, eel-like fish whose body plan has barely changed in roughly 360 million years.

In a study published in Science on June 18, a team of researchers led by SU Bing from the Kunming Institute of Zoology of the Chinese Academy of Sciences, along with collaborators from BGI-Research and Liaoning Normal University, built the first three-dimensional, single-cell atlas of an entire lamprey brain, which is essentially a high-resolution map showing the location of every cell and which genes are active in each cell.

The researchers found that although lampreys diverged from jawed vertebrates about 450 million years ago, their brains share strikingly similar gene-expression patterns with the mouse across many regions. This finding suggests that the common ancestor of all vertebrates likely already had a well-organized, molecularly complex brain.

However, the researchers showed that each lineage also evolved its own innovations: the lamprey has unique midbrain neurons and oversized "Müller cells," while mammals went on to build a more elaborate, layered cortex.

Moreover, the atlas hints at how neuronal types became more specialized over the course of evolution. The lamprey has a versatile cell type called the anamniote-enriched neuron (AEN) that carries both excitatory and inhibitory signals at once—a process described as "moonlighting."

Comparing living species across the vertebrate tree, the researchers found these "moonlighting" cells to be common in lampreys and zebrafish but rare in amniotes, which instead rely on "specialist" neurons with dedicated functions. The researchers suggest this contrast is linked to an ancient whole-genome duplication.

In addition, the researchers revealed that even the cerebellum, the brain's coordination hub, shows early roots: lamprey cells resembling cerebellar neurons point to a diffuse, primitive "cerebellum-like region."

Overall, the study helps reconstruct the evolutionary blueprint of the ancestral vertebrate brain and provides new insights into how vertebrate brains became increasingly complex over time.

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Journal

Science

DOI

10.1126/science.aea2535 

Article Title

Lamprey 3D single-cell transcriptomics reveals ancestral and specialized features of the vertebrate brain

Article Publication Date

18-Jun-2026