Tag Archives: population

The Health of the Population Suffered Due to the Roman Occupation of Britain.

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Reconstruction of the city of Wroxeter in Roman Britain

Ivan Lapper/British Heritage/Heritage Images/Getty Images

During Roman rule, the health standards of Britain’s populace declined, particularly in city environments.

There’s a common conception that the Romans introduced civilization and its various advantages, exemplified by a scene in Monty Python’s Life of Brian, where Reg, portrayed by John Cleese, rhetorically asks, “Aside from hygiene, medicine, education, wine, security, irrigation, roads, freshwater systems, and sanitation, what have the Romans ever done for us?”

However, researchers have recognized health issues for at least a decade. A study titled Declining public health in Iron Age Britain indicates that after the Romans arrived in 43 AD, the population continued to thrive even after their departure.

Currently, Rebecca Pitt and her team at the University of Reading in the UK analyzed 646 ancient human bones, with 372 belonging to children under three and a half years at death, and 274 from adult women aged 18 to 45. These remains originated from 24 Iron Age and Romano-British sites in southern and central England, spanning from the 4th century before Roman arrival to the 4th century AD, coinciding with the Roman exit.

Pitt evaluated age based on the pelvic features of adults and the teeth of children. By studying both potential mothers and their infants, she aims to gain insights into the stressors that impacted different generations during Roman dominance.

“A mother’s health significantly affects her child’s well-being, and environmental factors during crucial developmental stages can have enduring effects on health,” remarks Pitt.

Pitt scrutinized the bones and teeth for irregularities such as lesions or fractures indicative of conditions like tuberculosis, osteomyelitis, or dental diseases. She utilized X-rays to investigate the internal bone structure, highlighting changes in development stemming from malnutrition or deficiencies in vitamins C and D.

Her findings suggest that the adverse health outcomes linked to Roman occupation were especially apparent in two major urban centers: the Roman administrative town of Venta Belgarum (now Winchester) and Corinium Duvennorm (Cirencester).

Overall, 81 percent of urban Roman adults exhibited bone abnormalities compared to 62 percent of Iron Age individuals, while no significant differences were noted between Iron Age and rural Roman populations. Furthermore, only 26% of Iron Age children presented such issues, in contrast to 41% from Roman rural areas and 61% in Roman urban settings.

“A notable issue among non-adults in urban settings was rickets, indicating insufficient vitamin D from sunlight,” states Pitt.

She proposes that these health challenges, which persisted across generations, were attributable to new diseases brought by the Romans, along with the class disparities and infrastructure they established, which led to restricted resource access and overcrowded, polluted living conditions for those of lower social standing.

“My father enjoys telling jokes. Life of Brian reveals, however, that the Romans had a significantly negative impact on our health, affecting numerous generations,” observes Pitt.

Martin Millett, a professor at Cambridge University, expressed that this discovery is fascinating, suggesting that the effects may be underestimated if the buried individuals belonged to higher social classes who might have experienced better health, although he does not believe the observations are strictly urban-related.

“These urban settings are not the vast medieval towns known for deep poverty and high population densities,” he notes. “What we may be witnessing is an expanding divide between the wealthy and impoverished, with the Roman Empire’s economic and social systems exacerbating this gap over time.”

Richard Maggwick, a professor at Cardiff University, also remarked that the Roman legacy did not equitably benefit everyone. “While we gained better sanitation, hygiene, and medical knowledge, accessibility remains a crucial question,” he states. “The truth is that not everyone benefited, and it took time for these advantages to reach various social strata.”

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Source: www.newscientist.com

Eighty Percent of the Global Population Now Resides in Urban Areas

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Eixample district in Barcelona, Spain

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Currently, over 80 percent of the global population resides in urban areas, a statistic that’s on the rise, emphasizing the necessity for cities to enhance both human health and environmental sustainability, as detailed in a significant United Nations report.

The latest Outlook for Global Urbanization report, published in 2018, indicated that 55 percent of the population lived in urban settings. However, these estimates vary internationally based on disparate definitions of urban and rural regions. For instance, Denmark considers an urban settlement to be one with a population of about 200, while Japan sets the threshold at 50,000, obscuring the understanding of global urbanization.

To clarify matters, Sarah Hertog, a researcher for the United Nations in New York, identified urban areas as those with at least 50,000 inhabitants and a density of 1,500 people per square kilometer, or cities with a minimum of 5,000 people and 300 people per square kilometer.2 “For the first time, we applied a consistent definition across all countries,” Hertog stated.

The researchers analyzed satellite and national survey data from 237 nations and territories to project global urbanization trends for 2025. Their findings indicated that 45 percent of the world’s population currently resides in cities, most within urban areas of fewer than 250,000 inhabitants, meaning a total of 81 percent of people are urban residents, with the last 19 percent in rural regions.

Statistical models incorporating factors like aging and migration patterns predict that by 2050, 83 percent of the global population will inhabit cities rather than rural settings. Although the overall number of city and town residents will rise until 2050, the rural population, mainly influenced by the Democratic Republic of the Congo, is expected to peak in the 2040s and subsequently decline until 2050.

These new estimates will assist the United Nations in tracking progress towards its goals. Hertog noted that the aim is to achieve the 11th Sustainable Development Goal, which aspires to make urban areas more inclusive, safe, resilient, and sustainable by 2030. The outcomes will also be included in a report by the Intergovernmental Panel on Climate Change to help inform policies to mitigate climate change.

Factors driving urban population growth differ by region. In eastern and southern Asia, rural-to-urban migration is predominant. “People migrate not just for job opportunities and education, but also for social interactions,” according to Hertog. While international migration significantly influences Europe and North America, in sub-Saharan Africa, the rise is largely attributable to higher birth rates compared to death rates.

The increase in urbanization presents both challenges and opportunities for the environment. As urban populations expand city limits, improper public transport planning can lead to urban sprawl, increasing car dependency and carbon emissions. Conversely, thoughtful planning can yield more energy-efficient transit options than those offered in rural areas.

Urbanization also impacts health. For instance, residents in urban settings are typically more susceptible to air pollution and extreme heat, which correlate with issues like cardiovascular problems and a higher risk of Alzheimer’s disease, as stated by Andrea Mechelli from King’s College London. Moreover, the scarcity of green spaces in certain urban locales can lead to heightened anxiety and cases of depression, he emphasizes.

However, urbanization also offers health advantages. “Healthcare in urban settings tends to be more accessible and comprehensive compared to rural areas,” notes Mechelli. “Additionally, social connections are easier to establish in cities, where individuals can find like-minded people, unlike in rural regions where one might need to travel for hours to meet others with similar interests.”

This does not imply that urbanization should be halted or that city living is undesirable. Mechelli concluded, “This report underscores the urgency to enhance our urban environments, making them greener and more livable, which would yield numerous benefits.”

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Source: www.newscientist.com

Just 1% of the Global Population Follows Healthy and Sustainable Eating Habits, Major Report Reveals

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Recent global assessments of the food system reveal that fewer than 1% of individuals consume diets beneficial to both the planet and human health.

Nevertheless, adopting a healthier dietary approach could prevent up to 15 million premature deaths annually and could decrease global greenhouse gas emissions by as much as 20%.

The findings are part of a 2025 Report by the Eat-Lancet Committee, which consolidates insights from nutritionists, climate experts, economists, physicians, social scientists, and agricultural scholars from over 35 countries.

The research team evaluated the effects of current food systems on human health and the environment, concluding that food production poses risks to five crucial Earth systems that are essential for human survival.

These five critical threats include climate change, land degradation, water scarcity, nitrogen and phosphorus pollution, and human-induced contaminants like pesticides and microplastics.

However, transforming the food system to ensure healthy diets for everyone could restore these systems to a safe state and enhance human well-being.

“If everyone adopts a healthy diet, by 2050, 100 billion people could sustain themselves on 7% less land than what is currently utilized,” stated Dr. Fabrice Declerck, EAT’s Chief Science Officer, in an interview with BBC Science Focus. “This has never happened in the history of food production. We have very few resources needed to feed more individuals.”

Justice was a significant aspect of the report, emphasizing the need for equitable wages for food workers and fairer access to food resources – Credit: Anuchasiribisanwan via Getty

Scientists have estimated that 6.9 billion individuals consume excessive amounts of food, particularly meat, dairy, sugar, and ultra-processed items, while 3.7 billion struggle to find access to nutritious food.

As a result, the report advocates for adherence to a planetary health diet (PhD), which emphasizes fruits, vegetables, nuts, legumes, and whole grains.

In a PhD, half of your plate should consist of vegetables, fruits, and nuts, while 30% should be dedicated to whole grains. The remaining portion should be a protein source, with a focus on legumes like beans and lentils.

Meat, fish, and dairy are optional within the PhD framework, with established limits, but the diet allows for flexibility. For instance, one can remain within guidelines even with a weekly intake of up to 200g of beef.

Declerck notes that the diet is adaptable to individual tastes, encouraging people to incorporate their cultural preferences.

“In fact, I believe traditional diets often more accurately reflect health,” he mentioned.

The planet’s healthy food guidelines aim to enhance human health while also benefiting the environment, as stated in the report – Credit: Carl Hendon

Currently, only 1% of individuals meet the report’s dietary suggestions. Declerck emphasized that scientists are not ready to pinpoint the locations of these individuals, given the numerous variations among countries.

“But these individuals reside in societies where they can access healthy diets and earn a livable wage,” he added.

Declerck further remarked that the best examples of healthy eating are often found in middle-income countries, particularly within the Mediterranean basin, the Indian subcontinent, and Southeast Asia.

For middle-income nations, the challenge lies in avoiding a shift toward a Western diet while maintaining cultural dietary traditions.

Amidst concerns regarding the climate crisis, Declerck stated that the report presents a “surprising” opportunity to enhance both human health and environmental well-being simultaneously.

“We encourage individuals to consume a wider variety of foods, celebrate their own cultural contributions, explore diverse culinary traditions, and enjoy the richness of food diversity,” he asserted. “This is beneficial not only for your personal health but also contributes significantly to the health of our planet as a whole,” Declerck concluded.

The research’s co-author, Professor Johann Lockstrom, co-chair of the committee and director of the Potsdam Institute for Climate Impact Research, stated: “The evidence is irrefutable. It is not only feasible to transform the food system, but it is crucial for ensuring a safe, fair, and sustainable future for all.”

Justice formed another key component of the report, highlighting the fact that the wealthiest 30% of the population accounts for over 70% of food-related environmental impacts.

“Those of us who are unhealthy and walk blocking others’ rights to a secure environment must take action,” the report emphasized.

The findings call for immediate measures to reform the global food system for the benefit of human health, justice, and environmental sustainability.

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Source: www.sciencefocus.com

New Research Indicates Harbin Fossils Are Linked to Denisovan Population

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The renowned “Harbinclanium” dates back at least 146,000 years, previously classified as a distinct species: Homo Longhi.

Reconstruction of Harbin’s individuals in his habitat. Image credit: Chuang Zhao.

The skull of Harbin was unearthed in 1933 during the construction of a bridge over the Songhua River in Harbin city, Jiangxi Province, China.

Due to systematic recovery processes over extensive periods, precise locations and data pertaining to the fossil layers were unfortunately lost.

The fossils are notably large, surpassing all other archaic humans, exhibiting a low and elongated shape that lacks the rounded contours typical of modern human crania.

Features include a large, nearly square eye socket, a pronounced brow ridge, a wide mouth, and prominent teeth.

The cranial capacity is estimated at 1,420 mL, aligning within the ranges of Homo sapiens, Neanderthals, and surpassing earlier Homo species.

This specimen, often referred to as the “Dragon Man” fossil, likely represents individuals under the age of 50.

In a recent study, Dr. Qiaomiei Fu from the Chinese Academy of Sciences and his colleague from the Institute for Vertebrate Paleontology and Paleontology performed a detailed analysis of the fossils and their dental calculus.

They identified over 308,000 peptides, around 20,000 proteins, and confirmed the presence of 95 endogenous proteins.

Additionally, they found 122 single amino acid polymorphisms (SAPs) unique to humanity, reaffirming the classification of the Harbin specimens within the Homo genus.

Significantly, three variants unique to Denisovans were identified, establishing a phylogenetic connection between the Harbin fossil and Denisova 3, small fragments from Denisova Cave.

“Prior to this discovery, Denisovan fossils were sparse and fragmented, complicating our understanding of their morphology and evolutionary background,” the researchers stated.

“The Harbin Fossils, identified as a new species Homo Longhi, exhibit crucial morphological similarities to Denisovan remains found elsewhere.”

Harbin’s personal portrait. Image credit: Cicero Moraes, doi: 10.6084/m9.figshare.24648591.

The researchers also successfully extracted mitochondrial DNA (mtDNA) from the dental calculus of the fossil.

The findings confirmed that Harbin individuals belonged to the early mtDNA lineage of Denisovans.

“The mtDNA aligns with the variability observed in Denisovan mtDNA and is associated with the lineage carried by early Denisovan individuals in southern Siberia, previously identified in Denisova Caves,” the authors mentioned.

“This indicates that Denisovans occupied a broad geographical range across Asia during the mid-Pleistocene.”

The detection of Denisovan mtDNA in Harbin’s skull aids in linking Denisovans with distinct morphological traits and recognizing other specimens as Denisovan, particularly when ancient DNA is either poorly preserved or challenging to procure.

For instance, fossils from Dali, Jinniushan, and Hualongdong display comparable morphological features to the Harbin skull, suggesting they may represent the Denisovan population.

“The connection between Denisovan mtDNA and Harbin skull morphology enhances our understanding of the morphological relationships between Denisovans and other central Pleistocene fossils in East Asia,” the researchers concluded.

“Moreover, exploring host DNA from dental calculus opens new avenues for genetic research related to the mid-Pleistocene.”

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Qiaomei Fu et al. Harbin’s personal proteome from the late Pleistocene. Science published online on June 18th, 2025. doi:10.1126/science.adu9677

Qiaomei Fu et al. Denisovan mitochondrial DNA from the dental calculus of the Harbin skull, over 146,000 years old. Cell published online on June 18th, 2025. doi: 10.1016/j.cell.2025.05.040

Source: www.sci.news

Are you underestimating the actual global population count?

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Population estimates for rural China may be incorrect

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Rural population estimates underestimate the number of actual people living in these areas by at least half, researchers argue. However, the findings are contested by demographics. Demography says such underestimation is unlikely to change the head count of a nation or world.

Josiasláng-ritter And while his colleagues at Aalto University in Finland were working to understand the extent to which the dam construction project resettled people, they continued to get numbers that differed significantly from official statistics while estimating the population.

For the purposes of the investigation, they used data on 307 dam projects in 35 countries, including China, Brazil, Australia and Poland, completed between 1980 and 2010, and obtained the number of people reported to have resettled in each case as the population of the area prior to evacuation. We then cross-checked these numbers to break down the area into a square grid, and estimated the number of people living in each square to reach the total.

Láng-Ritter and his colleagues discovered that what they say is a clear contradiction. Their analysis shows that the most accurate estimates increased the actual number by 53% on average, while the worst was 84%. “We were very surprised to see how big this underestimation is,” he says.

The official UN estimate of the world population is around 8.2 billion, but Láng-Ritter says the analysis shows perhaps much higher, but refuses to give a specific number. “Today, population estimates are likely to be conservative accounting, and there is reason to believe that these over 8 billion people are significantly more common,” he says.

The team suggests that these counting errors will occur. This is because rural census data are often incomplete or unreliable, and population estimation methods have historically been designed for the best accuracy in urban areas. Correcting these systematic biases is important to avoid inequality for rural communities, researchers suggest. This can be done by improving census in such areas and recalibrating the population model.

If rural population estimates are far more abolished, it could have a significant impact on the provision of government services and plans, Láng-Ritter said. “The impact may be very large because these datasets are used for so many different types of actions,” he explains. This includes planning transportation infrastructure, building health facilities, and risk reduction efforts in natural disasters and epidemics.

However, not everyone is convinced by the new estimate. “The study suggests that the number of local populations in places where you live in the country is incorrectly estimated, but it is not clear that this necessarily implies that the national estimates of the country are incorrect.” Martin Cork At Stockholm University, Sweden.

Andrew Tame The University of Southampton in the UK will oversee WorldPop. This was one of the data sets that the study suggested, lowering the population by 53%. He says that grid-level population estimates are based on combining high-level census estimates with satellite data and modeling, and that the quality of satellite images before 2010 is known to inaccurate such estimates. “The more time we go back, the more those problems come,” he says. “I think that’s something that’s well understood.”

Láng-Ritter believes new ways are needed as data quality remains a problem. “With the data has improved dramatically within 2010-2020, it is very unlikely that the issues we identified have been fully resolved,” he says.

Stuart Giel Basten In Hong Kong, the University of Science and Technology points out that most of the team’s data comes from China and other parts of Asia and may not apply globally. “I think it’s a very big jump to say that there is a very large undercount in other places like Finland, Australia, Sweden, etc. with a very sophisticated registration system based on one or two data points.” láng-ritter admits this limitation but supports the work. “The countries we saw are very different and the rural areas we surveyed have very different characteristics, so we are confident we will provide a representative sample of the whole of the globe.”

Despite some reservations, Gietel-Basten agrees to Láng-Ritter on one point. “I certainly agree with the conclusion that we should not only invest more in rural data collection, but come up with more innovative ways to count people,” he says.

But the idea that the official world population should expand to billions of people as “unrealistic,” Gietel-Basten says. Tatem is more convincing. “If we’re really insufficient in that mass, it’s a massive news story and it goes against everything in the thousands of other datasets,” he says.

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Source: www.newscientist.com

Webb’s discovery of brown dwarf candidates hints at first wealthy population outside of the Milky Way

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Astronomers using the NASA/ESA/CSA James Webb Space Telescope detected a population of 64 brown dwarf candidates with masses ranging from 50 to 84 Jupiter masses in the star cluster NGC 602.

This image of NGC 602 includes data from Webb's NIRCam (near-infrared camera) and MIRI (mid-infrared instrument) instruments. Image credits: NASA / ESA / CSA / Webb / P. Zeidler / E. Sabbi / A. Nota / M. Zamani, ESA & Webb.

NGC602 is a very young star cluster, about 200,000 light-years away in the constellation Hydra, about 2 to 3 million years old.

Also known as ESO 29-43, this star resides in the wings of the Small Magellanic Cloud.

NGC 602's local environment closely resembles that of the early Universe, with very low abundances of elements heavier than hydrogen and helium.

The presence of dark clouds of dense dust and the fact that the cluster is rich in ionized gas also suggests the presence of an ongoing star formation process.

Together with the associated HII region N90, which contains clouds of ionized atomic hydrogen, this cluster provides a rare opportunity to examine star formation scenarios under conditions dramatically different from those in the solar neighborhood.

Using Webb, Dr. Peter Zeidler and his colleagues at AURA and ESA were able to detect 64 brown dwarf candidates in NGC 602. This is the first rich population of brown dwarfs to exist outside the Milky Way.

“It is possible to detect objects at such great distances only with incredible sensitivity and spatial resolution in the right wavelength range,” Dr. Zeidler said.

“This has never been possible and will remain impossible from the ground for the foreseeable future.”

“So far, about 3,000 brown dwarfs are known, and they all live in our galaxy,” said Dr. Elena Mangiavakas, also from AURA and ESA.

“This discovery highlights the ability to use both Hubble and Webb to study young star clusters,” said Dr. Antonella Nota, executive director of the International Space Science Institute.

“Hubble showed that NGC 602 hosts very young, low-mass stars, but only Webb can conclusively confirm the extent and significance of substellar mass formation in this cluster. Hubble and Webb are an amazingly powerful telescope duo!”

“Our results are very consistent with the theory that the mass distribution of objects below the hydrogen burning limit is simply a continuation of the stellar distribution,” Dr. Zeidler said.

“They seem to form the same way, they just haven't accumulated enough mass to become full stars.”

NSF astronomer Dr. Elena Sabbi said, “Studying the newly discovered metal-poor young brown dwarfs in NGC 602 will shed light on how stars and planets formed under the harsh conditions in the early universe. We are getting closer to uncovering the secrets of this.” NOIRLab, University of Arizona, Space Telescope Science Institute.

“These are the first substellar objects outside the Milky Way,” Manjavakas said.

“We need to be prepared for new breakthrough discoveries in these new objects.”

of result will appear in astrophysical journal.

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peter zeidler others. 2024. A candidate for a subsolar metallic brown dwarf is discovered in the Small Magellanic Cloud. APJ 975, 18; doi: 10.3847/1538-4357/ad779e

Source: www.sci.news

Insights into the Future of Humanity from the 2024 United Nations World Population Prospects Report

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“Demographic composition has changed significantly in recent years,” Li Junhua, the U.N. Under-Secretary-General for Economic and Social Affairs, said in a news release.

The report predicts that the world’s population will continue to grow over the coming decades, from 8.2 billion in 2024 to a peak of nearly 10.3 billion in the next 50 to 60 years. But population won’t keep growing forever: By 2100, the world’s population is expected to return to 10.2 billion, 6% lower than UN experts predicted a decade ago.

The United Nations’ last population assessment, released in 2022, suggested humanity could reach 10.4 billion people by the late 2000s, but falling birth rates in some of the world’s largest countries, including China, are one of the reasons why the population peak will come sooner than expected.

More than half of countries have fertility rates below 2.1 children per woman, or the “replacement rate,” the number of children each woman needs to have to avoid population decline.

An additional 48 countries, including Vietnam, Brazil, Turkey and Iran, are also expected to see their populations peak over the next 30 years.

India’s population is 1.4 India’s population is expected to surpass China’s in 2022, surpassing 2 billion and becoming the world’s most populous country. India’s population is also expected to continue growing until the middle of this century, according to the report.

However, China’s population continues to decline.

“China has experienced a rapid and significant decline in births in recent years,” said Patrick Garland, head of the Population Estimates and Projections Division at the United Nations Population Division.

“The changes China has undergone in the past generation are among the fastest in the world,” Garland said.

Without immigration, the United States would also face a population decline. It is one of about 50 countries projected to continue experiencing population growth due to increased immigration. The U.S. population is projected to grow from 345 million in 2024 to 421 million by the end of the century.

People pass through a crowded street in Kampala, Uganda. Since 2013, Uganda’s population has grown by 13 million people, or nearly 40 percent, second only to the Democratic Republic of Congo.
Badru Katumba/AFP via Getty Images

A growing country is likely to exacerbate problems related to consumption, greenhouse gas emissions, and other drivers of global warming. A growing population also means more people are exposed to climate risks such as droughts, heat waves, and other extreme weather events that are intensified by global warming.

“Just because a challenge might emerge 60 years from now doesn’t mean it’s pointless to talk about it now,” said Dean Spears, an associate professor of economics at the University of Texas at Austin.

“Decades from now, people will be talking about these new demographic changes with the same level of academic and societal concern that we are talking about today about climate change,” Spears said.

Countries where population growth is expected to continue through to 2054 include India, Indonesia, Pakistan and Nigeria. In parts of Africa, including Angola, the Central African Republic, the Democratic Republic of the Congo, Niger and Somalia, populations are expected to double dramatically between 2024 and 2054, according to the United Nations.

But a growing population on Earth does not necessarily mean that climate change will occur faster. Most of the world’s fastest growing regions are also countries that have historically contributed the least to global warming. These regions are also typically disproportionately affected by climate change.

The report notes that life expectancy has recovered after the impact of the pandemic. Global life expectancy will be 73.2 years in 2023, up from the pandemic low of 70.9 years in 2021 and higher than the pre-pandemic level of 72.4 years five years ago. Global life expectancy is projected to reach 81.7 years in 2100.

As life expectancy increases and birth rates fall, the world’s population is ageing. Projections show that by 2080, people aged 65 and over will outnumber children under 18. By 2023, there will be almost three times as many children as people aged 65 and over.


Source: www.nbcnews.com

Over 100 Shark Species at Risk of Drastic Population Declines by 2100

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Ocean warming threatens to reduce golden tiger shark populations

Shutterstock/Podlonaya Elena

The world's egg-laying shark populations could be hit hard by the end of the century as increasing ocean warming and acidification destroys embryos, potentially affecting more than 100 shark species.

This discovery was made possible by the discovery of the giant sandbar shark (Termitesis found in the Mediterranean Sea and the Northeast Atlantic Ocean. About 40 percent of sharks reproduce by laying tough, skinned egg capsules that contain the embryos. These shark embryos are highly sensitive to changes in ocean conditions, such as temperature and pH levels. The ocean absorbs excess carbon dioxide from the atmosphere, causing it to warm up and become more acidic.

Noémie Coulon Researchers at the French National Museum of Natural History exposed catshark eggs to a variety of ocean conditions, including monthly temperature changes, in a lab tank. Coulomb and his colleagues chose the catshark because it is one of the most abundant shark species in Europe.

In the first test, A “middle-of-the-road” climate scenario A 2.7°C increase in temperature above pre-industrial levels by 2100, with a corresponding decrease in pH of 0.2, is projected. A second scenario (in which the world continues to rely heavily on fossil fuels) projects a 4.4°C increase in temperature and a 0.4 decrease in pH by the end of the century. The third is a historical baseline, which recreates water temperature and pH in shark habitats from 1995 to 2014.

A tiny spotted catshark embryo inside an egg

Noémie Coulon

The researchers then simulated conditions as the embryos developed over the next four months, and found dramatic differences in the embryos' hatching success rates depending on the experimental conditions: In the baseline and moderate scenarios, about 82% of the eggs hatched. But in the warmest scenario, only five of the 45 embryos survived, a loss of almost 90%.

“We were really shocked by the death rate,” Coulon said. “It will probably cause a population collapse.”

“Even a relatively short period of warmth, such as a particularly warm August, was enough to cause the hatching to fail. Based on these results, Coulon predicts other egg-laying sharks, including endangered or vulnerable species like the nurse hound, will be similarly devastated.”

But their extinction is not doomed, says Coulon: “If we make an effort to limit global warming to around 2°C, this species may be able to survive.”

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Source: www.newscientist.com

The mammoth population on Wrangel Island remained stable before extinction

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Mammoth (Mammutus primigenius) is isolated Wrangel Island Mammoths were discovered off the coast of Siberia approximately 10,000 years ago and survived for over 200 generations before going extinct approximately 4,000 years ago. To study the evolutionary events leading up to their extinction, scientists analyzed the genomes of 21 Siberian mammoths and found that mammoth populations recovered quickly from a severe bottleneck and remained demographically stable for the next 6,000 years.

Three mammoths (Mammutus primigenius) walks up a snow-covered hill with snow-capped mountains rising behind him above a dense green forest of fir trees. Image by Daniel Eskridge.

“We can confidently reject the idea that the population was so small that it was destined to go extinct for genetic reasons,” said Dr Love Dalen, an evolutionary geneticist at the National Academy of Sciences of Canada. Center for PaleogeneticsIt is a joint collaboration between the Swedish Museum of Natural History and Stockholm University.

“This means that it was probably just a chance event that caused the mammoths to go extinct, and if that chance event hadn't occurred, mammoths would still be around today.”

“In addition to shedding light on the population dynamics of woolly mammoths, analysis of the Wrangel Island mammoths could inform conservation strategies for this currently endangered animal.”

“The mammoth is an excellent system for understanding the ongoing biodiversity crisis and what happens from a genetic perspective when a species experiences a population bottleneck, because it reflects the fate of many modern populations,” said Dr Marianne DeHask, also from the Centre for Palaeogenetics.

To understand the genomic impact of the Wrangel Island bottleneck on mammoth populations, the researchers analyzed the genomes of 21 woolly mammoths, 14 from Wrangel Island and seven from the mainland population that existed before the bottleneck.

Overall, the samples span the woolly mammoth's existence over the past 50,000 years and provide insight into how the animal's genetic diversity has changed over time.

Compared to their mainland ancestors, the genomes of the Wrangel Island mammoths showed signs of inbreeding and low genetic diversity.

In addition to the overall low genetic diversity, Major histocompatibility complexA group of genes known to play important roles in the immune response of vertebrates.

The scientists showed that the genetic diversity of the population continued to decline, albeit at a very gradual rate, throughout the 6,000 years that the mammoths lived on Wrangel Island, suggesting that the population size remained stable until the end.

They also showed that the island's mammoth population gradually accumulated moderately deleterious mutations over its 6,000-year existence, but that the most deleterious mutations were slowly eliminated.

“If an individual had a highly deleterious mutation, they would basically not be able to survive, so over time those mutations would slowly disappear from the population. But we know that mammoths accumulated mildly deleterious mutations almost all the way up until their extinction,” Dr DeHask said.

“It's important to remember that current conservation programs will not be enough to simply re-establish populations to a reasonable size. They also need to be actively and genetically monitored, as these genomic effects could last for more than 6,000 years.”

The mammoth genomes analyzed in this study span a long period of time, but do not include the last 300 years of the species' existence.

However, the authors plan to excavate fossils from the final stages of the mammoth and analyze its genome sequence in the future.

“What happened to them at the end is still a mystery. We don't know why they went extinct after surviving fairly well for 6,000 years, but we think it was probably a sudden event,” Dr Dallen said.

“I think there's still hope we can figure out why they went extinct, but I can't make any promises.”

of Investigation result Published in the online journal this week cell.

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Marianne DeHask othersTemporal dynamics of genomic erosion in pre-extinction mammoths. cellPublished online June 27, 2024, doi: 10.1016/j.cell.2024.05.033

Source: www.sci.news

New Research Challenges Easter Island Population Decline Theory

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Easter Island (Rapa Nui) is often held up as an example where overexploitation of limited resources led to catastrophic population declines. A key element of this story is that the rapid rise and fall in pre-contact Rapa Nui population growth rates was caused by the construction and overexploitation of once-extensive rock gardens. However, the extent of rock gardens across the island, important for understanding food systems and demographic dynamics, needs to be better understood. New research by archaeologists from Binghamton University and Columbia University shows that the extent of this agricultural infrastructure was significantly smaller than previously claimed, and likely could not have supported the large populations assumed.

Map of Easter Island and its location in the southeastern Pacific Ocean. Image courtesy of Davis. others., doi: 10.1126/sciadv.ado1459.

In their study, Professor Carl Lipo of Binghamton University and his colleagues used modern techniques to more accurately estimate the number of rock gardens on Easter Island and their pre-human contact food production.

“This volcanic island was formed by an eruption a million years ago, so there has been enough time for rain to wash away the potassium, phosphorus, and nitrogen needed for plant growth,” Professor Lipo said.

“Salty sea spray further reduces soil fertility.”

“The soils on Rapa Nui were not particularly productive. When people arrived on the island, they had to deal with those constraints.”

“Their first method was slash-and-burn agriculture, which involved cutting down the trees on the island.”

“This temporarily restored nutrients to the soil, but once the trees died, islanders turned to other methods, such as composting plant waste and rock mulch.”

“The fertilization benefits from composting are not enough to support a culture's food supply. Rock mulch was sufficient, but it was a very labor-intensive process.”

“The islanders chipped away some of the exposed bedrock and mixed the stone chunks into the soil, restoring nutrients and protecting the soil from further weathering.”

Rock mulch has also been traditionally used by the Maori people of New Zealand, Native Americans in the American Southwest, and in other areas such as the Netherlands.

“We do it ourselves using non-organic fertilizers. We basically use machinery to break the rocks into smaller pieces, which is more effective because it creates a larger surface area,” Professor Lipo said.

“The Rapa Nui people are literally breaking rocks by hand and burying them in the soil.”

“The gardens also grow dryland taro and yams, but the main crops are dozens of varieties of sweet potato. But not all rockeries are ancient gardens,” said Dr Robert DiNapoli from Binghamton University.

But how many gardens were there on Easter Island? When Europeans first encountered the island, they reported that 10 percent of the island was covered in gardens. Researchers have previously used satellite imagery to map the rock gardens, but this has resulted in misidentifications of things like roads.

Rapa Nui is one of the most remote human settlements on Earth, more than 2,000 km from the nearest inhabited island (Pitcairn Island) and more than 3,700 km from the South American mainland. The island is small (164 km2) and has relatively limited soil productivity and freshwater sources. Image credit: Bjørn Christian Tørrissen / CC BY-SA 3.0.

The study authors used shortwave infrared (SWIR) satellite imagery and machine learning to come up with a more precise estimate, finding that the area covered by mulch is about 180 acres, far less than previously thought.

“SWIR imagery, primarily used for geological mapping, can distinguish mineral composition and water content,” said Dr. Dylan Davis, a postdoctoral researcher at Columbia University.

“Due to unique mineralogical characteristics and moisture patches, the rock gardens stand out from their surroundings.”

Using the latest estimates of the number of gardens, the researchers calculated that around 3,000 people lived on Easter Island at the time of European contact.

The oldest European records indicate a population of between 3,000 and 4,000, which is consistent with artifacts found on the island.

“What we're actually seeing here is that ecological constraints mean that islands just can't support that many people in the first place,” Dr Davis said.

“People actually changed the landscape to increase the amount of crops they could cultivate intensively, but the numbers were still very small.”

“This is not an example of ecological catastrophe, but rather an example of how people have managed to survive for a long time in a fairly sustainable way, despite very limited natural resources.”

“The misconception about the island's population size comes from the island's large and impressive moai statues and the assumption that it takes a large number of people to build such statues,” Prof Lipo said.

“Ecologists tend to use Easter Island as a model for how population size can lead to ecological catastrophe.”

“You can't use Easter Island as an example to suit your story.”

“We need to understand the island in its own context, because what it really tells us is quite different from what people believe.”

of Investigation result Published in today's journal Scientific advances.

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Dylan S. Davis others2024. Island-wide characterization of agricultural production casts doubt on the population collapse hypothesis for Rapa Nui (Easter Island). Advances in Science 10(25):eado1459; doi:10.1126/sciadv.ado1459

Source: www.sci.news

Washington state set to reintroduce grizzly bears in an effort to preserve population

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The federal government announced this week that grizzly bears will be reintroduced to Washington state’s North Cascade Mountains. The decision follows many years of intense and divisive debate.

But due to the complex process of capturing bears from British Columbia and northwestern Montana, transporting them by truck and helicopter, it will take many years before bears can venture into the remote and rugged terrain. It may also be costly.

“There’s a lot of work to do before we can schedule it,” said Jason Ransom, a wildlife biologist with North Cascades National Park. “Getting the planning right is critical to the success of a project like this.”

The National Park Service and U.S. Fish and Wildlife Service announced Thursday that over the next 5 to 10 years, a “founder population” of bears will be released into a secluded part of the forest.

This reintroduction will restore a keystone species to the North Cascades, one of the most protected landscapes in the United States. Grizzlies once roamed throughout the region, but were extensively hunted for their fur. The National Park Service reports that there has not been a confirmed bear sighting since 1996.

Both agencies plan to release between three and seven bears each year with the goal of reaching a population of 200 bears within 60 to 100 years.

The North Cascades are one of six areas where federal agencies are working to rehabilitate grizzly bears. Supporters believe that this effort will improve the overall ecosystem health.

Ransom mentioned that grizzly bears play a vital role in turning soil, spreading seeds, and adapting to various habitats for reproduction. Their versatility makes them resilient to environmental changes, including those caused by climate change.

But opponents express concerns about the safety risks grizzly bears may pose to humans, as well as the potential conflicts with farmers and ranchers in the surrounding areas. The reintroduction project is addressing these concerns by selecting a release site in high-quality habitat far from populated areas.

The federal government has designated the project’s grizzly bears as a “nonessential experimental population” under the Endangered Species Act, providing legal flexibility to manage potential conflicts and protect both humans and bears.

The process of capturing and releasing bears involves using culvert traps, anesthesia, veterinary examinations, and radio collars for tracking purposes. The gradual reintroduction process aims to allow humans and bears to adapt to each other in an environment that has been bear-free for decades.

Starting with 25 bears allows the population to grow slowly, giving both humans and bears a chance to coexist in the area that has been without bears for a long time.

Source: www.nbcnews.com

Researchers report a 30% decline in California’s western monarch population last year

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SAN FRANCISCO — The number of western monarch butterflies wintering in California declined by 30% last year, likely due to the high humidity, researchers announced Tuesday.

Volunteers visiting sites in California and Arizona around Thanksgiving removed 230,000 butterflies from 330,000 butterflies by 2022, according to the Xerses Society, an environmental nonprofit focused on invertebrate conservation. It is said that more than one fish was caught.

Populations of the orange and black insects have rebounded to hundreds of thousands in recent years. In 2020, the number of butterflies plummeted to just 2,000., the lowest on record. But even though the butterflies have recovered, their numbers are still far below what they were in the 1980s, when monarchs numbered in the millions.

Scientists say butterfly populations are critically low in western states because housing construction and increased use of pesticides and herbicides are destroying milkweed habitat along migratory routes. Says.

Climate change is also one of the main factors in the monarch butterfly's extinction, preventing the butterflies from migrating 3,000 miles (4,828 km) each year to coincide with spring and wildflower blooms.

“Climate change is creating challenges for many wildlife species, and the monarch butterfly is no exception,” said Emma Pelton, monarch butterfly conservation biologist at the Xerces Society. “We know that the severe storms we saw in California last winter, atmospheric rivers flowing back to back, are on some level connected to climate change.”

Western monarch butterflies migrate south from the Pacific Northwest to California each winter, returning to the same places and even the same trees, where they huddle together and stay warm. They breed multiple generations along the route until they arrive in California, usually in early November. When warm weather arrives in March, it spreads east of California.

East of the Rocky Mountains, another population of monarch butterflies migrates from southern Canada and the northeastern United States into central Mexico. Scientists estimate that monarch butterfly populations in the eastern United States have declined by about 80% since the mid-1990s, but the decline in the western United States is even steeper.

Source: www.nbcnews.com

Government suggests culling owl population to protect endangered species

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The U.S. Fish and Wildlife Service has proposed a plan to shoot hundreds of thousands of barred owls in West Coast forests over the next 30 years, arguing that the survival of one owl species depends on the extinction of another. The spotted owl, not native to the area, is displacing its genetically related barred owl, the bureau said.

Unless action is taken against barred owls, the spotted owl could disappear from parts of Washington and Oregon within a few years and eventually become extinct, according to service biologists.

This proposal is the latest effort to save the spotted owl, whose decline became a rallying point for environmentalists against logging in the Pacific Northwest in the 1980s. This plan raises questions about how far humans should go to save species and the cost of righting historic ecological wrongs, as the barred owls may have become established in the Pacific Northwest under human influence as European settlers spread westward.

The proposal calls for the “lethal removal” (killing with shotguns) of more than 470,000 barred owls in total and is open for public comment until January 16th. It may be difficult for the undiscerning eye to distinguish barred owls from spotted owls, as both have pale faces and mottled brown and white coats and belong to the same genus. However, barred owls are slightly larger, breed faster, are more aggressive, and are less discriminatory about where they live and what they eat.

The spotted owl population has declined by about 75 percent over the past 20 years, primarily due to barred owls, according to the U.S. Fish and Wildlife Service. The plan would eliminate the barred owls from 1-2% of its current range, and the removal of barred owls has been shown to stabilize the spotted owl population, although the impact has not been substantial.

Despite the dominance of barred owls, the population is likely to recover over time, and the cost of righting historic ecological wrongs is still uncertain. Wildlife biologists consulted with an ethicist about killing the animals, and while some animal rights groups disagree with the plan, a final proposal is expected to be released in the spring or summer after the public comment period on the USFWS proposal ends.

Source: www.nbcnews.com