Tag Archives: populations

Sea Cow Populations Have Shaped the Arabian Gulf Seagrass Ecosystem for Over 20 Million Years

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Paleontologists have discovered a significant concentration of dugong fossils at Al Masjabiya, an early Miocene dam site in Qatar. These fossils indicate that the Arabian Gulf has undergone various species of sea cows over the past 20 million years. One of these species is Salvacillen catalensis.

An artistic rendering of a group of Salvacillen catalensis foraging on the ocean floor. Image credit: Alex Boersma.

It has a robust body and a downturned snout adorned with sensitive bristles. Dugongs (dugong dugong) are closely related to manatees.

A key distinction between these aquatic herbivores, often referred to as sea cows, is their tails. Manatees possess a paddle-like tail, whereas dugongs feature a fluke-like tail that resembles that of a dolphin.

Dugongs inhabit coastal waters stretching from western Africa through the Indo-Pacific to northern Australia.

The Arabian Gulf hosts the world’s largest dugong population, making sea cows critical to the ecosystem.

As they graze on seagrass, dugongs alter the ocean floor, creating feeding channels that release buried nutrients into the surrounding waters for use by other marine life.

“We uncovered a distant ancestor of the dugong in a rock formation less than 16 kilometers (10 miles) from a bay with seagrass meadows, which is currently the primary habitat for dugongs,” stated Dr. Nicholas Pienson, curator of fossil marine mammals at the National Museum of Natural History.

“This region has served as the main habitat for sea cows for the past 21 million years, with different species occupying this role over time.”

Few locations preserve as many bones as Al Masjabiya, a fossil site in southwestern Qatar.

The bone beds were initially identified in the 1970s during mining and oil exploration, when geologists found a large number of “reptilian” bones scattered across the desert.

Paleontologists revisited the area in the early 2000s and soon realized that these fossils belonged to sea cows, not ancient reptiles.

Using the surrounding rock layers as a guide, Dr. Pienson and his team dated the bone bed to the early Miocene, approximately 21 million years ago.

They found fossils indicating that this area was once a shallow marine habitat teeming with sharks, barracuda-like fish, prehistoric dolphins, and sea turtles.

Researchers identified over 170 different sites containing sea cow fossils throughout the Al Masjabiya location.

This renders the bone bed the richest trove of fossilized sea cow remains globally.

The fossilized bones from Al Masjabiya bore a resemblance to modern dugongs, although ancient sea cows still had hind limb bones, which contemporary dugongs and manatees have lost through evolution.

The prehistoric sea cows found here exhibited straighter snouts and smaller tusks compared to their living counterparts.

Researchers classified Al Masjabiya’s fossil sea cow as a new species: Salvacillen catalensis.

“Using a national name for this species seemed fitting, as it clearly indicates the location where the fossil was discovered,” said Dr. Ferhan Sakal, a researcher at Qatar Museums.

Estimated weight: 113 kg (250 lbs), Salvacillen catalensis would weigh as much as an adult panda or a heavyweight boxer.

Nonetheless, it was among the smaller sea cow species ever found, with some modern dugongs weighing nearly eight times as much as Salvacillen catalensis.

Based on the fossils, scientists theorize that the region was rich in seagrass beds more than 20 million years ago, during an era when the bay was a hotspot of biodiversity, supported by sea cows nurturing these aquatic meadows.

“The density of al-Mashabiya’s bone bed provides a significant clue. Salvacillen catalensis acted as seagrass ecosystem engineers in the early Miocene, much like dugongs do today,” Dr. Pienson added.

“Though the evolutionary agents have completely changed, the ecological roles have remained the same.”

The findings are documented in a published paper available at: Peer J.

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ND Pienson et al., 2025. The abundance of early Miocene sea cows from Qatar demonstrates the repeated evolution of eastern Tethyan seagrass ecosystem engineers. Peer J 13: e20030; doi: 10.7717/peerj.20030

Source: www.sci.news

Intense Heat Leads to Significant Decline in Tropical Bird Populations

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The black-throated trogon of the Amazon is rapidly declining

Luismix/Getty Images

Several bird populations have seen declines of up to 90% in tropical regions like the Amazon and Panama, even in areas of the rainforest that remain largely untouched . Current research indicates that extreme heat is likely the primary factor driving these declines.

From 1950 to 2020, intense heatwaves led to a 25-38% decrease in bird populations inhabiting these biodiverse tropical regions, as reported by Maximilian Cotts and his team from Barcelona’s Super Computing Center.

The researchers have yet to utilize these findings to forecast future bird population trends as global temperatures continue to rise, but early indicators are concerning. “The situation looks grim,” Cotts remarks.

He and his team have initiated a comprehensive analysis of global bird populations using the Living Planet Database. This dataset, however, does not include seabirds. Additional data on habitat destruction was sourced from the Hyde database for global environments, along with historical weather and climate data from the European Centre for Medium-Range Weather Forecasts.

The researchers compared this information to identify correlations that could shed light on the observed changes in bird populations. Their findings suggest that habitat loss is a significant driver of decline, corroborating earlier studies, particularly in regions with latitudes between 21° and 43° north or south.

In contrast, extreme heat is the predominant factor affecting bird survival in tropical areas, where many species often exist at the edge of their heat tolerance limits. If these limits are exceeded, they risk mortality , explains Kotz. Even if they manage to survive an intense heat episode, their health is typically compromised, diminishing their reproductive success.

The team is also analyzing how the exacerbation of extreme heat is attributable to anthropogenic climate change, and how bird populations would behave in a scenario without warming. This approach enables researchers to gauge the impact of climate change on bird abundance.

Although such attribution studies have been traditionally employed to assess extreme weather events related to climate change, Kotz notes that this is the first instance of applying this methodology to evaluate ecological repercussions.

There remains a significant lack of data regarding bird population trends, particularly in tropical regions. Kotz acknowledges this deficiency but believes there is enough evidence to draw meaningful conclusions. He cautions that insufficient data in these areas may lead to an underestimation of the impacts.

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Source: www.newscientist.com

Forests with Healthy Wildlife Populations Store Four Times More Carbon

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Capuchin Monkeys and Their Role in Seed Dispersal in Tropical Forests

Carlos Grillo/Getty Images/iStockphoto

Tropical ecosystems, rich in animal biodiversity that aids in seed dispersal, can sequester carbon at rates up to four times higher than fragmented forests lacking these animals or where their movements are limited.

“This underscores the connection between the loss of animal biodiversity and the processes that intensify climate change,” explains Evan Fricke from the Massachusetts Institute of Technology. “We’ve lost the potential for tropical forest regeneration.”

While animals only store a fraction of the carbon in their environment, their activities significantly influence ecosystem carbon dynamics. Notably, species such as monkeys, birds, and rodents play a crucial role in dispersing a wide variety of seeds.

Fricke mentions that “linking this to a prolonged process like carbon capture across landscapes proved quite challenging.”

Fricke and his team examined over 3,000 plots in tropical forests where trees are returning and successfully reabsorbing carbon following disturbances. They then assessed the degree of movement and diversity disruption of seed-dispersing animals in each plot, with findings influenced by forest fragmentation and data from monitored animals.

They discovered that increased disruption in seed disperser movement correlated with lower rates of carbon accumulation. The forests with the most disturbed animal behaviors grew four times faster than those with minimal disruption.

On average, disturbances in animal diversity and movement patterns that disperse seeds halved the carbon accumulation potential of affected plots. This indicates that such disruptions had a more detrimental impact than other factors inhibiting tree regrowth, such as fires and livestock grazing.

In contrast, forests experiencing the least disruption sequestered carbon more rapidly than monoculture wood farms. “Natural growth enhanced by animal activity presents a cost-effective and biodiversity-friendly recovery method,” states Fricke.

Earlier ecological models indicated that seed dispersers might significantly influence carbon storage; however, this study further elucidates the critical role these animals play, according to Oswald Schmitz from Yale University. “It highlights their importance now and into the future.”

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Source: www.newscientist.com

Experts predict significant decline in bee populations by 2025

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Entomologists at Washington State University predict that the US Honeybee colony may decline by up to 70% by 2025.

The university revealed in a News Release that over the last decade, annual losses of Honeybee Colonies averaged between 40% and 50%. However, this year, a combination of factors such as nutritional deficiencies, mites infections, viral diseases, and potential pesticide exposure during the previous pollination season contributed to even higher losses.

Priya Chakrabarti Basu, assistant professor of health and pollinator behavior at WSU, expressed concern over the increasing losses, stating, “The demand for pollination remains high, putting pressure on beekeepers to maintain colonies to meet these needs.”

The implications could be significant as about 35% of the world’s food depends on pollinators, as stated by the National Institute of Food and Agriculture.

Flocking bees form clusters in Las Vegas trees.
Gabe Ginsberg / Getty Images

Brandon Hopkins, professor of pollinator ecology at WSU, warned that higher colony losses could result in increased costs for farmers relying on bee colonies.

Hopkins added, “This level of national loss could potentially lead to beekeepers facing bankruptcy, affecting farmers who depended on them for pollination.”

The Honeybee industry had a production value of around $350 million in 2023, as reported by the Agriculture Department.

Hopkins noted that extreme Honeybee losses also pose a particular risk to the almond industry this year.

He stated, “The almond industry heavily relies on robust colonies, and this year, due to low supply, any beehives are in high demand.”

Reflecting on the situation, Hopkins added, “I haven’t seen a decline like this since the colony collapse in 2008.”

Source: www.nbcnews.com

The incidence of colorectal cancer is increasing in young populations globally

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It’s not entirely clear why colorectal cancer is increasing among adults under 50

Steve Gschmeisner/Science Photo Library

The incidence of colorectal cancer in young adults is increasing worldwide, but this trend appears to be most prevalent in high-income countries.

Previous studies have shown that the incidence of bowel or colorectal cancer is increasing. Over the past few decades, it has increased in this age group in Western countries, including the United States, Canada, Australia, and the United Kingdom. This has led to speculation that Western lifestyles, including a diet high in meat and processed foods, may be to blame.

To better understand the extent of the problem, song hyunah Researchers from the American Cancer Society in Atlanta, Georgia, and colleagues looked at the incidence of colorectal cancer in 50 countries and territories around the world. They typically used the World Health Organization’s database to collect data on incidence rates from 1975 to 2017, although some countries started reporting this information several years after 1975. Ta.

The research team found that the incidence of colorectal cancer among people aged 25 to 49 is rising in 27 countries and territories. These also include non-Western countries such as Japan and less wealthy countries such as Turkey, raising the possibility that Western lifestyles are not solely behind this trend.

The increase is also unlikely to be related to improved screening tests, the researchers said in the paper, as most countries do not routinely test people for colorectal cancer until age 50.

However, all 27 countries and territories have high or very high scores on the United Nations Human Development Index, which is based on life expectancy, education level, and per capita income.

Additionally, all but six are considered high-income earners, according to the World Bank. Unlike most of the high-income countries studied, in these six countries, cases of colorectal cancer among older people are increasing at the same or faster rate than among younger people.

“I think there’s still evidence of trends that economic development and westernization of lifestyles are really having an impact,” he says. Andrew Chan The Harvard University researchers noted that many countries are adopting aspects of this lifestyle as their economies grow. for example, Japanese meat intake It increased more than seven times between 1961 and 2021.

“Having said that, I think we need to take into account the fact that there are probably other factors at play, such as environmental contaminants,” Chan says.

The researchers note that their study has several limitations, the most obvious being that countries in Africa, Asia and small islands were underrepresented. For example, only one African country was included: Uganda. Some countries did not have complete datasets. For example, India’s figures represent only 4 percent of the population.

Still, these findings could improve our understanding of how colorectal cancer incidence varies in many countries and help devise new ways to prevent the disease, Zhang said. say.

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Source: www.newscientist.com

Study finds evidence of multiple instances of Denisovan populations interbreeding with modern humans

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The identification of a new human group called the Denisovans has been one of the most exciting discoveries in human evolution over the past decade. Unlike Neanderthal remains, the Denisovan fossil record consists of only a few skeletal fragments. Several Denisovan populations, which likely had vast geographic ranges, adapted to different environments and through multiple different interbreeding events that helped shape early human history, according to a new study. I passed on some of my genes.

Portrait of a young Denisovan woman based on a skeletal profile reconstructed from ancient DNA methylation maps. Image credit: Maayan Harel.

Denisovans are an extinct hominin group first identified through genome sequences determined from finger bone fragments found in the Denisova Cave in the Altai Mountains of southern Siberia.

“This was one of the most exciting discoveries in human evolution in the past decade,” said Dr Linda Ongaro, a researcher at Trinity College Dublin.

Subsequent genome analysis showed that Denisovans diverged from Neanderthals 400,000 years ago, and that at least two distinct Denisovan populations intermingled with the ancestors of modern Asians.

The only physical remains of Denisovans discovered so far are a finger bone fragment, three teeth, and a skull fragment from the Denisovan Cave. Jaw bones and rib bones from Baisiya Karst Cave on the northeastern edge of the Tibetan Plateau.

“It's a common misconception that humans evolved suddenly and cleanly from one common ancestor, but the more we learn, the more we realize that interbreeding with different hominins occurred and helped shape the humans we know today. ” said Dr. Ongaro.

“Unlike Neanderthal remains, the Denisovan fossil record consists only of finger bones, jaw bones, teeth, and skull fragments.”

“However, by exploiting the remaining Denisovan parts of modern humans' genomes, scientists have found evidence of at least three past events in which genes from different Denisovan populations invaded modern humans' genetic characteristics. I discovered.”

Each of these shows different levels of relatedness to the sequenced Altai Denisovans, illustrating the complex relationships between these sister lineages.

Dr. Ongaro and his colleague Professor Emilia Huerta Sánchez of Trinity College Dublin and Brown University, in their new paper, have a wide geographical range, from Siberia to Southeast Asia, and from Oceania to the south. We have reviewed evidence pointing to several likely Denisovan populations. America has adapted to a unique environment.

They also outlined a number of genes of Denisovan origin that conferred advantages to modern humans in different environments.

“Among these are genetic loci that confer tolerance to hypoxia or hypoxic conditions, which makes a lot of sense because we see it in the Tibetan population. Multiple genes that increase immunity. Another “Influences lipid metabolism and provides heat when stimulated by cold, providing benefits to Arctic Inuit populations,” Dr. Ongaro said.

“There are many directions for future research that will help us more fully understand how Denisovans influenced modern humans, including uncovering currently hidden traces of Denisovan ancestry. This includes more detailed genetic analyzes in understudied populations that have the potential to

“Additionally, by integrating more genetic data with archaeological information, finding more Denisovan fossils will certainly fill in some more gaps.”

of paper Published in a magazine natural genetics.

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L. Ongaro & E. Huerta-Sánchez. History of multiple Denisovan introgressions in modern humans. Nat Genetpublished on November 5, 2024. doi: 10.1038/s41588-024-01960-y

Source: www.sci.news

Study finds Neanderthal populations were genetically and socially isolated for tens of thousands of years

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In 2015, archaeologists discovered Neanderthal fossils. Grotte Mandolin is located on the Mediterranean coast of France, in the shadow of a rock overhanging directly into the Rhône River valley. Nicknamed Thorin, the fossil is one of the most similar Neanderthal remains found in France since its discovery in Saint-Césaire in 1979. Globe Institute researcher Martin Sikora and his colleagues combined archaeological, chronostratigraphic, isotopic, and genomic analyses to reveal that Thorin belonged to a Neanderthal population that remained genetically isolated for 50,000 years. Apart from Thorin’s lineage, they found evidence of gene flow in the genome of the Les Côtés Neanderthal from another lineage that diverged from the ancestral lineage of European Neanderthals more than 80,000 years ago. The findings suggest the existence of multiple isolated Neanderthal communities in Europe close to the time of extinction and shed light on their social organization. Despite the close geographical proximity of these populations, there was limited, if any, interaction between the different Neanderthal populations during the last millennium.

Neanderthal. Image courtesy of Abel Grau, CSIC Communication.

“When we look at the Neanderthal genome, we see that they were quite inbred and didn’t have a lot of genetic diversity,” Dr Sikora said.

“They’ve lived in small groups for generations.”

“Inbreeding is known to reduce the genetic diversity of populations, which if continued over long periods of time can have negative effects on the viability of the population.”

“The newly discovered Neanderthal genome is from a different lineage to other late Neanderthals studied so far.”

“This supports the idea that Neanderthal social organization was different from that of early modern humans, who appear to have been more connected.”

“In other words, compared to Neanderthals, early modern humans were more likely to connect with other groups, which was advantageous for their survival.”

“This is purely speculation, but the concept of being able to communicate more and exchange knowledge is something humans can do that Neanderthals, who were organized in small groups and lived isolated lives, may not have been able to do to some extent.”

“And that’s an important skill,” noted Dr Tarshika Vimala, a population geneticist at the University of Copenhagen.

“We see evidence that early modern humans in Siberia, living in small communities, formed so-called mating networks to avoid problems with inbreeding, something that wasn’t seen in Neanderthals.”

Thorin’s fossils were first discovered in Mandolin Cave in 2015. Mandolin Cave is a cave that is thought to have been the site of an early Homo sapiens But not at the same time, and he is still being slowly unearthed.

Based on Thorin’s location in the cave deposits, archaeologists have speculated that he may have lived approximately 45,000 to 40,000 years ago.

To determine his age and relationships to other Neanderthals, the team extracted DNA from his teeth and jaw and compared his entire genome sequence to previously sequenced Neanderthal genomes.

Surprisingly, initial genome analysis suggested that Thorin’s genome was very different from other late Neanderthals and very similar to the genomes of Neanderthals who lived more than 100,000 years ago, suggesting that Thorin is much older than archaeological estimates.

To solve the mystery, the researchers analyzed isotopes from Thorin’s bones and teeth to gain insight into the type of climate he lived in. Late Neanderthals lived during the Ice Age, while early Neanderthals enjoyed a much warmer climate.

Isotopic analysis showed that Thorin lived in a very cold climate and was identified as a late Neanderthal.

Compared to previously sequenced Neanderthal genomes, Thorin’s genome is most similar to the individual from Gibraltar, leading the authors to speculate that Thorin’s population may have migrated from Gibraltar to France.

“This means that a previously unknown Neanderthal population was present in the Mediterranean, stretching from the westernmost tip of Europe to the Rhône Valley in France,” said Dr Ludovic Slimac, researcher at Toulouse-Paul Sabatier University and CNRS.

Knowing that Neanderthal communities were small and isolated may hold the key to understanding their extinction, because isolation is generally thought to be detrimental to a population’s fitness.

“It’s always a good thing for one group to have contact with another,” Dr Vimala said.

“Prolonged isolation limits genetic diversity and reduces the ability to adapt to changes in climate and pathogens. It’s also socially limiting, as they don’t share knowledge or evolve as a group.”

But to truly understand how Neanderthal populations were structured and why they became extinct, researchers say many more Neanderthal genomes need to be sequenced.

“If we had had more genomes from other regions over the same time period, we probably would have found other deeply structured populations,” Dr Sikora said.

A paper on the results of this study was published today. journal Cell Genomics.

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Ludovic Slimak others2024. The long genetic and social isolation of Neanderthals before their extinction. Cell Genomics 4(9):100593;doi: 10.1016/j.xgen.2024.100593

Source: www.sci.news

Research: Thick plant populations move to shade one another and share sunlight

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Typically, plants grow in crowded environments where neighboring plants compete for light while shading each other. The presence of neighboring plants varies through space and time, and plants have developed the ability to detect neighboring plants and grow away from their shade. Although it is generally accepted that these responses help plants increase their individual light exposure, it is not clear how plants find solutions that are beneficial for them as a whole. In a new study, physicists from Tel Aviv University and elsewhere focus on the spontaneous self-organized pattern formation of sunflower flocks mediated by shade avoidance. Their analysis reveals that circumnavigation (the innate movement of plants) results in random perturbations that follow a restricted random walk.

Circling is widespread in plant systems and is commonly associated with exploratory behavior, but its role is difficult to quantitatively understand. otherswere the first to report their role in promoting optimal growth patterns in dense plant populations that shade each other. Image courtesy of Manuel H.

“Previous studies have shown that when sunflowers are planted close together in a field and shade each other, they will grow in a zigzag pattern, one forward and one backward, to avoid shading each other,” said Professor Yasmin Meros of Tel Aviv University.

“That way the plants can grow side by side, maximizing the light they receive from the sun and maximizing photosynthesis overall.”

“In fact, plants know how to distinguish between the shadow of a building and the green shadow of their leaves.”

“When they sense the shadow of a building, they usually don't change their growth direction because they know it won't have any effect.”

“But when a plant senses shadow, it grows away from the shadow.”

In this study, the researchers investigated the question of how sunflowers “know” how to grow optimally (i.e. to capture the most sunlight collectively) and analysed the growth dynamics of sunflowers in the lab that exhibit a zigzag pattern.

Meros and his colleagues grew sunflowers in high-density environments, photographing them every few minutes as they grew, and then stitched together the images to create a time-lapse video.

The researchers followed the movements of each sunflower and observed the blossoms dancing en masse.

According to the authors, Darwin was the first to recognise that all plants grow by exhibiting a kind of cyclical movement (circumlocution), and that both stems and roots exhibit this behaviour.

But until now, apart from a few examples such as vines that grow in large circular motions searching for something to grab hold of, it hasn't been clear whether this is an artefact or an important feature of growth. Why would a plant expend energy growing in a random direction?

“As part of our research, we carried out a physical analysis to capture the behaviour of each sunflower in the colony and found that they dance to find the optimal angle to avoid blocking the sunlight of their neighbours,” Professor Meros said.

“We statistically quantified this movement and showed through computer simulations that these random movements are used collectively to minimize the amount of shadowing.”

“We were also very surprised to see that the distribution of sunflower stride lengths was so wide, spanning three orders of magnitude, from nearly zero displacement to moving two centimetres in either direction every few minutes.”

“Sunflower plants take advantage of the fact that they can use both small, slow steps and large, fast steps to find the optimal arrangement for their population,” Professor Meros said.

“That means that if the steps are narrow or wide, the arrangement will increase mutual shading and reduce photosynthesis.”

“It's like a crowded dance party, where people dance around to get more space. If you move too much, you get in the way of the other dancers, but if you move too little, it doesn't solve the crowding problem, because one corner of the square will be very crowded and the other side will be empty.”

“Sunflowers also exhibit similar communication dynamics: a combination of response to the shade of neighboring plants and random movement without regard to external stimuli.”

of result Published in the journal Physical Review X.

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Chantal Nguyen others2024. Noisy turning movements promote self-organized shade avoidance in sunflowers. Physical Review X 14 (3): 031027; doi: 10.1103/PhysRevX.14.031027

Source: www.sci.news

Photos Show Plastic Threatening Bird Populations on Paradise Island

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Lord Howe Island

Neil Hadaway

Jutting out into the Tasman Sea between Australia and New Zealand is the curved, crescent-shaped volcanic remnant of Lord Howe Island. Measuring 10 kilometres in length and 2 kilometres at its widest point, the rocky island is covered in lush, unspoiled forest and boasts a sandy, coral-rich lagoon.

“This is paradise.” Neil HadawayA photographer who went there to document the activities of the marine research group. drifting“There are birdsongs all around, beautiful coral reefs and golden sand beaches.” Among the bird calls is the shearwater (Aldena CarneipesOf the total, approximately 22,000 breed on the island.

Petrel chick (Ardenna carneipes)

Neil Hadaway

But life there is not ideal, and newly hatched petrel chicks, like the one pictured above, are under threat from increasing marine plastic pollution. Adult petrels mistake plastic debris in the sea for food and end up feeding it to their young. In fact, Adrift researchers have found that the amount of plastic ingested by chicks is increasing every year. One of the team, pictured below, sifts through chunks of plastic in the stomach of just one bird.

As a result, these chicks become increasingly underdeveloped, with dozens dying each year from starvation and plastic-related diseases.

“This island may be magical,” Hadaway said, “but it's also full of frustration and sadness.”

He says stricter laws against plastic pollution are needed to protect populations of petrels, which locals affectionately call “muttonbirds” (see above) after their taste.

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Source: www.newscientist.com

Chile’s Humboldt Penguins Face Extinction as Populations Decline Rapidly

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The Humboldt penguin populations along Chile’s central coast have seen a significant decline, making them one of the most at-risk species out of the world’s 18 penguin species and facing the threat of extinction, according to experts.

A recent survey conducted by scientists on two islands off the central Chilean coast revealed a drastic decrease in breeding pairs or active nests, from 842 last year to just one this year.

Veterinarian Paulina Arce, who specializes in penguins, noted that populations have either decreased or remained stable on all the islands that were studied.

“This could lead to something even more serious – the extinction of the species,” Arce cautioned.

The Humboldt penguin (Spheniscus humboldti) is found on the Pacific coast of Chile and Peru and is named after the Humboldt Current that it inhabits. These flightless birds can weigh up to 5 kg (11 lbs) and grow up to 70 cm (2 ft 3 in) in length as adults.

Diego Penaloza, president of the Safari Conservation Foundation, identified marine pollution, lack of pet supervision, and disturbance of nesting sites as the main threats to penguins in the wild.

Moreover, avian influenza exacerbated by the El Niño weather pattern has led to devastating consequences for penguins and other wildlife, causing breeding rates for Humboldt penguins to plummet almost to zero, as outlined by Javier Mesa, biodiversity conservation manager for CONAF, the national forestry agency.

“Because of the avian flu and the El Niño weather phenomenon, all the food was swept southwards, resulting in a near-zero breeding rate for penguins in northern Chile and the deaths of many more penguins,” Mesa explained. “It was a perfect storm.”

Source: www.nbcnews.com

Study finds that competition between species was a significant factor in the growth and fall of human populations

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Traditionally, climate has been thought to be the cause of the emergence and extinction of human species. However, interspecific competition is known to play an important role in most vertebrates. A new study shows for the first time that competition has been the basis of speciation (the rate at which new species emerge) over five million years of human evolution.It also means that our speciation patterns homo The pedigree was different from most others.

a homo heidelbergensis, Neanderthals and Cro-Magnons. Image credit: SINC / Jose Antonio Peñas.

“We have ignored how competition between species has shaped our own evolutionary tree,” says Dr Laura van Holstein, an anthropologist at the University of Cambridge.

“The effects of climate on the human species are only part of the story.”

“In other vertebrates, species form to fill ecological niches. Darwin's finches, for example, have evolved large beaks for cracking nuts, while others have evolved large beaks for eating certain insects. Some have evolved small beaks to accommodate them. Once their respective resource niches are filled, competition ensues, no new finches emerge, and extinction takes over.”

Dr Van Holstein and Professor Robert Foley from the University of Cambridge used Bayesian modeling and phylogenetic analysis to show that, like other vertebrates, most species of humans formed when competition for resources and space was low. It was shown that

“The pattern seen in many early humans is similar to all other mammals,” van Holstein says.

“The speciation rate increases, then levels off, at which point the extinction rate begins to increase. This suggests that competition between species was a major evolutionary factor.”

However, when the authors analyzed our group, homothe findings were “bizarre.”

for homo The pattern of evolution of the lineage leading to modern humans suggests that interspecific competition actually led to the emergence of even newer species, a complete departure from trends seen in almost all other vertebrates. It's a reversal.

“The more types there are, the more homo The more there are, the higher the rate of speciation,” Dr. van Holstein said.

“So once those niches were filled, something caused more species to emerge. This is almost unprecedented in evolutionary science.”

The closest comparison she found was a species of beetle that lives on the island. On islands, confined ecosystems can produce unusual evolutionary trends.

“The evolutionary patterns we see across species are homo “The direct link to modern humans is more closely related to island beetles than to other primates or other mammals,” Dr van Holstein said.

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Marine reserves do not aid in the recovery of fish populations

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Grunts and gray grunts in Holchan Marine Reserve off the coast of Belize

Pete Oxford/ILCP

Fish populations in Caribbean marine reserves have not recovered, according to a 12-year study. Researchers say poor enforcement of marine protection regulations, coastal development and rising water temperatures are likely to blame.

Stretching for more than 1,000 kilometers along the Caribbean coasts of Belize, Guatemala, Honduras, and Mexico, the Mesoamerican Reef is home to a wide range of wildlife, including more than 500 species of fish and 65 species of coral.

Over the past few decades, governments in these countries have created many marine protected areas (MPAs) with the aim of protecting the precious biodiversity of coral reefs and restoring fish populations that have declined due to overfishing. I did. These areas may prohibit fishing during certain times of the year, prohibit certain types of fishing gear, and restrict other activities such as tourism and mining.

To evaluate the effectiveness of these MPAs, stephen canty Researchers from the Smithsonian Environmental Research Center in Maryland analyzed changes in fish biomass in 111 protected lands and 28 non-protected lands from 2006 to 2018. The data was collected during a survey by a scuba diver as part of the investigation. Initiatives for healthy coral reefs.

The researchers found that adult fish biomass increased in only 11 of the marine protected areas during the study period, indicating an increase in adult fish populations. Meanwhile, adult fish populations declined in 28 of the reserves and remained unchanged in the remaining locations. Less protected sites did see declines, but the declines were often smaller than the most protected sites.

The study found that 11 areas where fish populations have recovered have well-enforced MPA regulations and less fluctuation in sea surface temperatures. Sites with poor recovery showed opposite trends, including poor implementation of conservation measures, increased human activity in coastal areas, and increased temperature anomalies.

“Enforcement plays a huge role in whether some of these areas are successful or not,” Canty says. He suggests that local residents, who make a living from adult fish, should be given a greater role in managing MPAs. It's also important to ensure MPAs are located in areas that are better protected from climate change and easier to manage, he says.

“There's still a lot we don't know about marine protected areas,” team members say Justin Nowakowski, also located at the Smithsonian Environmental Research Center. “Therefore, it is important to be able to look to the past to optimize how he positions and manages his MPAs in the future.”

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Source: www.newscientist.com