When the dinosaurs died, so did forests-and tree-dwelling birds

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The asteroid that wiped out dinosaurs from the Earth about 66 million years ago also led to the extinction of the first tree-dwelling birds, a study has found.

So it has always been thought that after a few years of an "impact winter" caused by dust blocking sunlight, there was rapid global warming much like what is happening today. If the same asteroid struck this afternoon, it would be lights out for humankind.

"The end-Cretaceous event is the fifth mass extinction - we're in the sixth", said Dunn. "Forest loss was only one of several factors working in combination that determined which bird lineages survived", Jingmai O'Connor, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthroplogy in China, tells The Atlantic.

The asteroid that ended the reign of the dinosaurs slammed into rocks rich in carbonates, releasing huge quantities of carbon dioxide into the atmosphere.

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"Today, birds are the most diverse and globally widespread group of terrestrial vertebrate animals - there are almost 11,000 living species", Field said in a statement. But birds can be fragile: over 1,000 bird species have been driven to extinction by human activity to date. Among surviving species, population sizes were probably devastated.

Paleobotanist Dr Antoine Bercovici from the Smithsonian Institution analysed the plant fossil record before and after the asteroid strike.

So, how did birds manage to make it through this bleak phase of Earth's history before thriving in its wake? They then tracked the evolutionary relationship of birds and how bird ecology changed over their existence.

It's estimated that the initial meteor impact at the end of the Cretaceous period (also known as the K-Pg event), blew down trees in a 1,500 km (932 miles) radius, leaving the 110-mile wide Chicxulub crater on the lip of Mexico's Yucatan peninsula. Forest fires broke out all over the world.

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Findings from a newly published study goes to show the dangers of burning fossil fuels and polluting the atmosphere with carbon dioxide. We performed a statistical analysis of the ecological habits of modern birds to work out if their ancestors were more likely to live in the trees than on the ground, a process called ancestral ecological reconstruction.

"We concluded that the temporary elimination of forests in the aftermath of the asteroid impact explains why arboreal birds failed to survive across this extinction event", said Field. According to the study, very few of the avian creatures survived the event.

They can be compared to today's tinamous, small-bodied, flying and ground-dwelling relatives of ostriches and emus that live in Central and South America. This supports the idea that many different groups of birds from this time evolved to move into the trees repeatedly and independently.

What does this all mean? The crash created a chain reaction and affected the environment, leading to the disappearance of dinosaurs. "We know that the diversity of bird communities is impacted by the availability of forests - when forests are cut down in favor of, for example, palm oil monoculture, bird diversity is slashed".

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