Subscribe free to our newsletters via your
. Earth Science News .




Subscribe free to our newsletters via your




















EARLY EARTH
Megafaunal extinctions driven by too much moisture
by Staff Writers
Adelaide, Australia (SPX) Apr 20, 2017


"Grassland megafauna were critical to the food chains. They acted like giant pumps that shifted nutrients around the landscape", says lead author Dr Tim Rabanus-Wallace, from the University of Adelaide. "When the moisture influx pushed forests and tundras to replace the grasslands, the ecosystem collapsed and took many of the megafauna with it."

Studies of bones from Ice Age megafaunal animals across Eurasia and the Americas have revealed that major increases in environmental moisture occurred just before many species suddenly became extinct around 11-15,000 years ago. The persistent moisture resulting from melting permafrost and glaciers caused widespread glacial-age grasslands to be rapidly replaced by peatlands and bogs, fragmenting populations of large herbivore grazers.

Research led by the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, published this week in Nature Ecology and Evolution, has revealed that the ancient bones preserve direct biochemical evidence of the environmental upheavals, which can be traced through time.

Using 511 radiocarbon dated bones from animals such as bison, horse, and llamas the team was able to investigate the role of environmental change in the mysterious megafaunal extinctions, which claimed the vast majority of existing large land animals such as giant sloths and sabre-toothed cats.

"We didn't expect to find such clear signals of moisture increases occurring so widely across all of Europe, Siberia and the Americas," says study leader Professor Alan Cooper, ACAD Director. "The timing varied between regions, but matches the collapse of glaciers and permafrost and occurs just before most species go extinct.

The international team of researchers, including the University of Alaska Fairbanks, University of Oslo, the Yukon Government, and palaeontologists across Russia and Canada, measured nitrogen isotopes preserved in dated ancient animal bones and teeth recovered from permafrost areas and caves across Europe, Siberia, North and South America. They found distinctive biochemical signals reflecting massive increases of moisture on the landscape.

"Grassland megafauna were critical to the food chains. They acted like giant pumps that shifted nutrients around the landscape", says lead author Dr Tim Rabanus-Wallace, from the University of Adelaide. "When the moisture influx pushed forests and tundras to replace the grasslands, the ecosystem collapsed and took many of the megafauna with it."

"The idea of moisture-driven extinctions is really exciting because it can also explain why Africa is so different, with a much lower rate of megafaunal extinctions and many species surviving to this day,, says Professor Cooper.

"Africa's position across the equator means that grassland zones have always surrounded the central monsoon region. The stable grasslands are what has allowed large herbivores to persist - rather than any special wariness of hunters learned from humans evolving there."

Professor Matthew Wooller, of the University of Alaska Fairbanks, says: "We find that on different continents the climate changes happened at different times, but they all showed that moisture increased massively just prior to extinction. The really elegant feature of this study is that it produces direct evidence from the fossils themselves - these extinct creatures are informing us about the climate they experienced leading up to their own extinctions."

Research paper

EARLY EARTH
Early dinosaur 'cousin' discovered - and it's not like scientists thought it'd be
Chicago IL (SPX) Apr 17, 2017
If you asked paleontologists what the earliest ancestors of dinosaurs were like, most would put their money on the animals resembling miniature dinosaurs: small, meat-eating animals that walked on two legs. But in a paper published in Nature scientists describe the earliest known dinosaur relative: a six-foot-long lizard-like carnivore called Teleocrater rhadinus. "Teleocrater has unexpect ... read more

Related Links
University of Adelaide
Explore The Early Earth at TerraDaily.com

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

EARLY EARTH
US to honour 'dumb' refugee deal with Australia: Pence

Rights group urges China to release N. Korean refugees

'Is this Miami?': An Iraqi family's Colombian odyssey

Sri Lanka ends search for garbage survivors as toll hits 32

EARLY EARTH
Nature: 3-D-printing of glass now possible

Engineering technique is damaging materials research reveals

Finding order and structure in the atomic chaos where materials meet

Two-dimensional melting of hard spheres experimentally unravelled after 60 years

EARLY EARTH
Ukraine's Mariupol to be without hot water for months

Fewer sharks equals fatter fish, research shows

Sea scorpions: The original sea monster

Degraded coral imperils coastal people: study

EARLY EARTH
Methane seeps in the Canadian high Arctic

More Antarctic protections urged on World Penguin Day

Arctic river ice deposits rapidly disappearing

Reindeer at risk from Arctic hot spell

EARLY EARTH
New data unearths pesticide peril in beehives

Climatic effect of irrigation over the Yellow River basin

A better way to predict the environmental impacts of agricultural production

Researchers quantify grasslands' carbon storage value

EARLY EARTH
Atlantic storm season starts early, putting energy industry on notice

Nepal quake injured stalked by disability two years on

Report identifies grand challenges to better prepare for volcanic eruptions

At least 11 killed in Colombia floods: Red Cross

EARLY EARTH
Top conservationist wounded in Kenya gun attack

Morocco, US stage joint military exercise

Gambia's race to save its 'Roots' on Kunta Kinteh island

South Sudan war strains Uganda's generous refugee policy

EARLY EARTH
Indonesian hobbit evolved from African ancestor

Neuroscientists measure 'higher' state of consciousness

Putting social science modeling through its paces

Science says: Let a stranger pick your profile picture




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement