̽��ֱ�� of Cambridge - extinction

Conservation efforts are bringing species back from the brink

sc604 — Tue, 18 Mar 2025 18:30:46 +0000

A major review of over 67,000 animal species has found that while the natural world continues to face a biodiversity crisis, targeted conservation efforts are helping bring many species back from the brink of extinction.

First Australians ate giant eggs of huge flightless birds

fpjl2 — Wed, 25 May 2022 15:09:43 +0000

Scientists settle debate surrounding 'Thunder bird' species, and whether its eggs were exploited by early Australian people around 50,000 years ago.

Tree-dwelling mammals survived after asteroid strike destroyed forests

cmm201 — Thu, 14 Oct 2021 12:10:32 +0000

Overall, the study supports the hypothesis that the widespread destruction of forests following the asteroid’s impact favoured ground-dwelling mammals over their arboreal counterparts. However, it also provides strong evidence that some tree-dwelling animals also survived the cataclysm, possibly nesting in branches through the Cretaceous-Paleogene (K-Pg) extinction event.

“ ̽��ֱ��recovery of terrestrial vertebrate life following the end-Cretaceous asteroid impact was one of the most important events in the history of life on Earth,” said senior author Dr Daniel Field, from Cambridge’s Department of Earth Sciences. “In this study, we drew on our previous work at Cambridge to investigate whether there were similarities in the ecological attributes of avian and mammalian survivors of the end-Cretaceous mass extinction.”

̽��ֱ��K-Pg mass extinction event occurred when a meteor slammed into Earth at the end of the Cretaceous period. ̽��ֱ��impact and its aftereffects killed roughly 75% of the animal and plant species on the planet, including whole groups like the non-avian dinosaurs.

For the study, the researchers analysed patterns of substrate preferences among all modern mammals and their ancestors, working backwards from the present day to before the K-Pg extinction event by tracing these traits along numerous phylogenetic trees — diagrams that illustrate the evolutionary relationships among species.

“Our study takes advantage of an ongoing revolution in our understanding of the tree of life, only made possible by researchers working in association with natural history collections,” said co-lead author Jacob Berv, from the ̽��ֱ�� of Michigan, USA. “By integrating data from such collections with modern statistical techniques, we can address new questions about major transitions in evolutionary history.”

̽��ֱ��researchers classified each mammalian species as arboreal, non-arboreal, or semi-arboreal. To be considered arboreal, the species had to nearly always nest in trees. Categorising some species could be tricky. For example, many bat species spend a lot of time among trees but nest in caves, so bats were mostly categorised as non-arboreal or semi-arboreal.

“We were able to see that leading up to the K-Pg event, there was a spike in transitions from arboreal and semi-arboreal to non-arboreal habitat use across our models,” said co-lead author Jonathan Hughes, from Cornell ̽��ֱ��, USA.

̽��ֱ��work builds on a previous study led by Field, which used the same analytical method — known as ancestral state reconstruction — to show that all modern birds evolved from ground-dwelling ancestors after the asteroid strike.

“ ̽��ֱ��fossil record of many vertebrate groups is sparse in the immediate aftermath of the extinction,” said Field, who is also curator of ornithology at the Cambridge Museum of Zoology. “Analytical approaches like ancestral state reconstruction allow us to establish hypotheses for how groups like birds and mammals made it through this cataclysm, which palaeontologists can then test when additional fossils are found.”

̽��ֱ��analysis helps illuminate ecological selectivity of mammals across the K-Pg boundary despite the relatively sparse fossil record of mammalian skeletal elements from the periods immediately preceding and following the asteroid’s impact.

How the tree-dwelling ancestors of primates survived the asteroid’s destruction is unclear. According to the authors, it’s possible that some forest fragments survived the calamity or that early primates and their relatives were ecologically flexible enough to modify their substrate preferences in a world mostly denuded of trees.

Reference:
Jonathan J Hughes et al. ‘Ecological selectivity and the evolution of mammalian substrate preference across the K–Pg boundary.’ Ecology and Evolution (2021). DOI: 10.1002/ece3.8114

Adapted from a Yale news release.

An asteroid strike 66 million years ago wiped out the non-avian dinosaurs and devastated the Earth’s forests, but tree-dwelling ancestors of primates may have survived it, according to a new study published in the journal Ecology and Evolution.

̽��ֱ��recovery of terrestrial vertebrate life following the end-Cretaceous asteroid impact was one of the most important events in the history of life on Earth

Daniel Field

Rod Waddington

Chimpanzee, Uganda

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Pollinators: first global risk index for species declines and effects on humanity

fpjl2 — Mon, 16 Aug 2021 15:01:29 +0000

̽��ֱ��Global South may have most to lose from pollinator loss, with Latin America at particular risk due to crop exports and indigenous cultures.

Scientists zero in on the role of volcanoes in the demise of dinosaurs

cmm201 — Mon, 29 Mar 2021 19:00:00 +0000

Earth has experienced five major extinction events over the last 500 million years, the fifth and most recent responsible for wiping out the dinosaurs 66 million years ago. Massive volcanic eruptions have been identified as a major driver in the environmental change which triggered at least three of these extinctions.

But what dealt the final blow to the dinosaurs – whether an enormous outpouring of lava from the Deccan Traps volcanic province in India or a large asteroid impact or perhaps a combination of the two – has remained open to debate.

Now, a multi-institutional research team, led by scientists from the City ̽��ֱ�� of New York (CUNY), and involving the ̽��ֱ�� of Cambridge, has, for the first time, accurately pinpointed the timing and amount of carbon released from Deccan Traps volcanic province. ̽��ֱ��new data means scientists can now assess the role of volcanism in climate shifts around the End-Cretaceous mass extinction.

̽��ֱ��team’s data show that CO₂ outgassing from Deccan Traps magmas can explain a warming of Earth’s global temperatures by roughly 3 degrees Celsius during the early phases of Deccan volcanism, but shows that the warming had lessened by the time of the mass extinction event.

Their findings support the theory that later Deccan magmas were not releasing that much CO₂, suggesting that volcanic carbon emissions didn’t play a major role in the dinosaur’s extinction.

“ ̽��ֱ��results are important because they show that major volcanic events can release substantial amounts of CO₂ not just from surface vents, but also from the large and complex plumbing systems that feed them. Even though volcanic carbon emissions alone couldn’t have triggered the mass extinction, our data highlights their influence on our planet's climate and habitability,” said co-author Professor Sally Gibson, from Cambridge's Department of Earth Sciences.

̽��ֱ��team had to search through hundreds of Deccan lava samples to identify suitable candidates to profile for their trapped CO₂ content. “In modern volcanic eruptions, such as the current one in Iceland, the CO₂ is trapped in crystals that are embedded in glassy fragments of rapidly cooled magma, but these are fragile and not preserved in the 65 million-year-old Deccan Traps,” said Gibson.

Recent research has identified a global warming event that occurred several hundred thousand years before the End-Cretaceous extinction. Some scientists have linked the eruption of the Deccan Traps to this warming event, but there is debate over whether the lavas that erupted could have released enough CO₂ into the atmosphere to cause it. Adding to this mystery, the lava volumes that erupted during this time are relatively small compared to the volumes erupted during subsequent stages of Deccan Traps activity. A major challenge in this debate has been the lack of CO₂ data on Deccan magmas from this time.

“ ̽��ֱ��new data highlights that carbon outgassing from lava volumes alone couldn’t have caused that level of global warming. But, when we factored in outgassing from magmas that froze beneath the surface rather than erupting, we found that the Deccan Traps could have released enough CO₂ to explain this warming event,” said lead-author Andres Hernandez Nava, a PhD student in ̽��ֱ��Graduate Center, CUNY Earth.

For their study, the team used lasers and beams of ions to measure the amount of CO₂ inside tiny droplets of frozen magma trapped inside Deccan Traps crystals from the End Cretaceous time period. They also measured the amounts of other elements, such as barium and niobium, which are indicators for how much CO₂ the magmas started out with. Finally, they performed modeling of latest Cretaceous climate to test the impacts of Deccan Traps carbon release on surface temperatures.

“Our lack of insight into the carbon released by magmas during some of Earth’s largest volcanic eruptions has been a critical gap for pinning down the role of volcanic activity in shaping Earth’s past climate and extinction events,” said Black, the study’s principal investigator and a professor in the Earth and Environmental Science program at ̽��ֱ��Graduate Center CUNY and City College of New York. “This work brings us closer to understanding the role of magmas in fundamentally shaping our planet’s climate, and specifically helps us test the contributions of volcanism and the asteroid impact in the end-Cretaceous mass extinction.”

Reference:
Hernandez Nava et al. Reconciling early Deccan Traps CO2 outgassing and pre-KPB global climate. PNAS (2021). DOI : 10.1073/pnas.2007797118

Adapted from a press release by ̽��ֱ��Graduate Center, CUNY.

Researchers have uncovered evidence suggesting that volcanic carbon emissions were not a major driver in Earth’s most recent extinction event.

Even though volcanic carbon emissions alone couldn’t have triggered the mass extinction, our data highlights their influence on our planet's climate and habitability

Sally Gibson

Loÿc Vanderkluysen, Drexel ̽��ֱ��

Deccan Traps, India

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A 100 million-year partnership on the brink of extinction

sc604 — Tue, 24 May 2016 23:25:07 +0000

A relationship that has lasted for 100 million years is at serious risk of ending, due to the effects of environmental and climate change. A species of spiny crayfish native to Australia and the tiny flatworms that depend on them are both at risk of extinction, according to researchers from the UK and Australia.

Look closely into one of the cool, freshwater streams of eastern Australia and you might find a colourful mountain spiny crayfish, from the genus Euastacus. Look even closer and you could see small tentacled flatworms, called temnocephalans, each only a few millimetres long. Temnocephalans live as specialised symbionts on the surface of the crayfish, where they catch tiny food items, or inside the crayfish’s gill chamber where they can remove parasites. This is an ancient partnership, but the temnocephalans are now at risk of coextinction with their endangered hosts. Coextinction is the loss of one species, when another that it depends upon goes extinct.

In a new study, researchers from the UK and Australia reconstructed the evolutionary and ecological history of the mountain spiny crayfish and their temnocephalan symbionts to assess their coextinction risk. This study was based on DNA sequences from crayfish and temnocephalans across eastern Australia, sampled by researchers at James Cook ̽��ֱ��, sequenced at the Natural History Museum, London and Queensland Museum, and analysed at the ̽��ֱ�� of Sydney and the ̽��ֱ�� of Cambridge. ̽��ֱ��results are published in the Proceedings of the Royal Society B.

“We’ve now got a picture of how these two species have evolved together through time,” said Dr Jennifer Hoyal Cuthill from Cambridge’s Department of Earth Sciences, the paper’s lead author. “ ̽��ֱ��extinction risk to the crayfish has been measured, but this is the first time we’ve quantified the risk to the temnocephalans as well – and it looks like this ancient partnership could end with the extinction of both species.”

Mountain spiny crayfish species diversified across eastern Australia over at least 80 million years, with 37 living species included in this study. Reconstructing the ages of the temnocephalans using a ‘molecular clock’ analysis showed that the tiny worms are as ancient as their crayfish hosts and have evolved alongside them since the Cretaceous Period.

Today, many species of mountain spiny crayfish have small geographic ranges. This is especially true in Queensland, where mountain spiny crayfish are restricted to cool, high-altitude streams in small pockets of rainforest. This habitat was reduced and fragmented by long-term climate warming and drying, as the continent of Australia drifted northwards over the last 165 million years. As a consequence, mountain spiny crayfish are severely threatened by ongoing climate change and the International Union for the Conservation of Nature (IUCN) has assessed 75% of these species as endangered or critically endangered.

“In Australia, freshwater crayfish are large, diverse and active ‘managers’, recycling all sorts of organic material and working the sediments,” said Professor David Blair of James Cook ̽��ֱ�� in Australia, the paper’s senior author. “ ̽��ֱ��temnocephalan worms associated only with these crayfish are also diverse, reflecting a long, shared history and offering a unique window on ancient symbioses. We now risk extinction of many of these partnerships, which will lead to degradation of their previous habitats and leave science the poorer.”

̽��ֱ��crayfish tend to have the smallest ranges in the north of Australia, where the climate is the hottest and all of the northern species are endangered or critically endangered. By studying the phylogenies (evolutionary trees) of the species, the researchers found that northern crayfish also tended to be the most evolutionarily distinctive. This also applies to the temnocephalans of genus Temnosewellia, which are symbionts of spiny mountain crayfish across their geographic range. “This means that the most evolutionarily distinctive lineages are also those most at risk of extinction,” said Hoyal Cuthill.

̽��ֱ��researchers then used computer simulations to predict the extent of coextinction. This showed that if all the mountain spiny crayfish that are currently endangered were to go extinct, 60% of their temnocephalan symbionts would also be lost to coextinction. ̽��ֱ��temnocephalan lineages that were predicted to be at the greatest risk of coextinction also tended to be the most evolutionarily distinctive. These lineages represent a long history of symbiosis and coevolution of up to 100 million years. However they are the most likely to suffer coextinction if these species and their habitats are not protected from ongoing environmental and climate change.

“ ̽��ֱ��intimate relationship between hosts and their symbionts and parasites is often unique and long lived, not just during the lifespan of the individual organisms themselves but during the evolutionary history of the species involved in the association,” said study co-author Dr Tim Littlewood of the Natural History Museum. “This study exemplifies how understanding and untangling such an intimate relationship across space and time can yield deep insights into past climates and environments, as well as highlighting current threats to biodiversity.”

Reference:
Jennifer F. Hoyal Cuthill et al. ‘Australian spiny mountain crayfish and their temnocephalan ectosymbionts: an ancient association on the edge of coextinction?’ Proceedings of the Royal Society B (2016). DOI: 10.1098/rspb.2016.0585

A symbiotic relationship that has existed since the time of the dinosaurs is at risk of ending, as habitat loss and environmental change mean that a species of Australian crayfish and the tiny worms that depend on them are both at serious risk of extinction.

We’ve now got a picture of how these two species have evolved together through time, and it looks like this ancient partnership could end with the extinction of both species.

Jennifer Hoyal Cuthill

100-million year partnership on the brink of extinction

David Blair, James Cook ̽��ֱ��

Light microscope image of the five tentacle temnocephalan Temnosewellia c.f rouxi from cultured redclaw crayfish

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Did dinosaur-killing asteroid trigger largest lava flows on Earth?

jeh98 — Tue, 12 May 2015 10:15:26 +0000

̽��ֱ��team of researchers, which included Dr Sally Gibson from Cambridge ̽��ֱ��’s Department of Earth Sciences, argue that the impact may have triggered most of the immense eruptions of lava in India known as the Deccan Traps. In a paper published in ̽��ֱ��Geological Society of America Bulletin they claim this would explain the “uncomfortably close” coincidence between the Deccan Traps eruptions and the impact, which has always cast doubt on the theory that the asteroid was the sole cause of the end-Cretaceous mass extinction.

̽��ֱ��Deccan Traps are a vast accumulation of igneous rock, and one of the largest volcanic features on Earth, located on the Deccan Plateau in India. Formed by huge lava flows, they cover an area of approximately 500,000km² and stretch across the Indian subcontinent from Mumbai to Kolkata.

“If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan … the chances of that occurring at random are minuscule,” said team leader Mark Richards, Professor of Earth and Planetary Science at the ̽��ֱ�� of California, Berkeley. “It’s not a very credible coincidence.”

While the Deccan lava flows, which started before the impact but erupted for several hundred thousand years after, probably spewed immense amounts of carbon dioxide and other noxious, climate-modifying gases into the atmosphere, it’s still unclear if this contributed to the demise of most of life on Earth at the end of the Age of Dinosaurs. “This connection between the impact and the Deccan lava flows is a great story and might even be true, but it doesn’t yet take us closer to understanding what actually killed the dinosaurs,” Richards added.

̽��ֱ��disappearance of the landscape-dominating dinosaurs is widely credited with ushering in the age of mammals, eventually including humans.

“Paul Renne’s group at Berkeley showed years ago that the Central Atlantic Magmatic Province is associated with the mass extinction at the Triassic/Jurassic boundary 200 million years ago, and the Siberian Traps are associated with the end-Permian extinction 250 million years ago, and now we also know that a big volcanic eruption in China called the Emeishan Traps is associated with the end-Guadalupian extinction 260 million years ago,” Richards said.

“Then you have the Deccan eruptions – including the largest mapped lava flows on Earth – occurring 66 million years ago coincident with the mass extinction of the dinosaurs. So what really happened?”

Richards teamed up with a multi-disciplinary group of experts to try to discover faults with his idea that the impact off the coast of Mexico triggered the Deccan eruptions, but instead came up with supporting evidence. Paul Renne, a Professor in Residence in the ̽��ֱ�� of California, Berkeley’s Department of Earth and Planetary Science and Director of the Berkeley Geochronology Center, re-dated the asteroid impact and mass extinction two years ago and found them essentially simultaneous. He also found they were within approximately 100,000 years of the largest Deccan eruptions, referred to as the Wai subgroup flows, which produced about 70 percent of the lavas that now stretch across the Indian subcontinent.

Richards and his team found pronounced weathering surfaces marking the onset of the huge Wai subgroup flows, which may indicate a period of inactivity in Deccan volcanism prior to the asteroid impact. Since the team’s manuscript was accepted for publication, new radioisotopic ages published by scientists at Princeton ̽��ֱ�� and preliminary ages from the Berkeley group have confirmed that the Wai lava flows closely postdate the asteroid impact.

“This was an existing massive volcanic system that had been there probably several million years, and the impact gave this thing a shake and it mobilised a huge amount of magma over a short amount of time,” Richards said.

“Based on the distances between erupting volcanoes and the epicentres of earthquakes, a large asteroid impact in Mexico could generate a huge earthquake (equivalent to magnitude 9 or greater) that would have enough seismic energy to shake magma chambers deep in the Earth below the Deccan and cause a sudden massive outpouring of lava, 100,000 years or so after the impact event itself,” explains Gibson.

“Our findings have broad implications for studies of past climate change, evolutionary biology, and how earthquakes might trigger volcanic eruptions.”

Inset image: Cross-sectional diagram to schematically illustrate the Deccan plume melting in the mantle beneath the Indian subcontinent 60 million years ago (from Richards et al., 2015)

Article originally published by the ̽��ֱ�� of California, Berkeley

̽��ֱ��asteroid that slammed into the ocean off Mexico 66 million years ago and killed off the dinosaurs probably rang the Earth like a bell, triggering volcanic eruptions around the globe, according to a multi-disciplinary team of scientists.

If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan … the chances of that occurring at random are minuscule

Mark Richards, ̽��ֱ�� of California Berkeley

SA Gibson

̽��ֱ��Deccan Traps in western India

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Economic success drives language extinction

fpjl2 — Wed, 03 Sep 2014 09:26:39 +0000

New research shows economic growth to be main driver of language extinction and reveals global ‘hotspots’ where languages are most under threat.

̽��ֱ��study’s authors urge for “immediate attention” to be paid to hotspots in the most developed countries – such as north Australia and the north-western corners of the US and Canada – where conservation efforts should be focused.

They also point to areas of the tropics and Himalayan regions that are undergoing rapid economic growth as future hotspots for language extinction, such as Brazil and Nepal.

̽��ֱ��study is published today in the journal Proceedings of Royal Society B.

̽��ֱ��researchers used the criteria for defining endangered species to measure rate and prevalence of language loss, as defined by the International Union for Conservation of Nature.

̽��ֱ��three main risk components are: small population size (small number of speakers), small geographical habitat range and population change – in this case, the decline in speaker numbers.

By interrogating huge language datasets using these conservation mechanisms, the researchers found that levels of GDP (Gross Domestic Product) per capita correlated with the loss of language diversity: the more successful economically, the more rapidly language diversity was disappearing.

“As economies develop, one language often comes to dominate a nation’s political and educational spheres. People are forced to adopt the dominant language or risk being left out in the cold – economically and politically,” said Dr Tatsuya Amano, from the ̽��ֱ�� of Cambridge’s Department of Zoology.

“Of course everyone has the right to choose the language they speak, but preserving dying language is important to maintaining human cultural diversity in an increasingly globalised world.”

In the northwest corner of North America, the languages of the indigenous people are disappearing at an alarming rate. Upper Tanana, for example, a language spoken by indigenous Athabaskan people in eastern Alaska, had only 24 active speakers as of 2009, and was no longer being acquired by children. ̽��ֱ��Wichita language of the Plains Indians, now based in Oklahoma, had just one fluent speaker as of 2008.

In Australia, aboriginal languages such as the recently extinct Margu and almost extinct Rembarunga are increasingly disappearing from the peninsulas of the Northern Territories.

As the researchers point out, “languages are now rapidly being lost at a rate of extinction exceeding the well-known catastrophic loss of biodiversity”. Major international organisations such as the United Nations and Worldwide Fund for Nature are now actively engaged in the conservation of linguistic diversity.

Amano says the global meta-analysis produced by the team using the species criteria is designed to complement the more specific, localised examples featured in many linguistic and anthropological research.

Unlike species extinction, however, language diversity has a potentially saving grace – bilingualism. Previous research from Cambridge’s Department of Theoretical and Applied Linguistics has shown that children who speak more than one language have multiple advantages in education, cognition and social interaction.

“As economies develop, there is increasing advantage in learning international languages such as English, but people can still speak their historically traditional languages. Encouraging those bilingualisms will be critical to preserving linguistic diversity,” added Amano.

Thriving economies are the biggest factor in the disappearance of minority languages and conservation should focus on the most developed countries where languages are vanishing the fastest, finds a new study.

People are forced to adopt the dominant language or risk being left out in the cold

Tatsuya Amano

Vanishing Voices film, ̽��ֱ�� of Cambridge

Himalayan Shaman

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