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

Rodiano Bonacci
Mag 26, 2018

"After a disaster like a forest fire or a volcanic eruption, the first plants to come back are the fastest colonizers-especially ferns", Dunn said. But what followed was probably even worse for the initial survivors of this apocalyptic event. "At all these locations we found a huge spike in fern growth immediately after the asteroid impact, which indicates the deforestation was global". Acid rain would have been triggered by the vapor, which would be rich in sulfates. Trees weren't able to practice photosynthesis due to the soot that blocked the atmosphere. "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".

According to a new study of fossil records from New Zealand, Europe, Japan, and North America by an global group of natural history and biology researchers, the asteroid extinction event that killed off most non-avian dinosaurs also wiped out forests around the world. "It talks to the power of collective science, and the significance of the fossil record for comprehending the life in the contemporary world". By studying bird fossils from the period prior to the impact and contrasting that with post-impact fossils, the researchers determined that ground-dwelling birds were the only ones who managed to tough it out, and they think they know why. They most likely lived off the hardiest grains and seeds that sustained the effect, along with pests.

She also notes that while the dinosaurs and their perching bird neighbors died 66 million years ago, their plight is relevant today. Jingmai O'Connor, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in China said, "Forest loss was only one of several factors working in combination that determined which bird lineages survived".

But the ground-dwelling birds that survived carried a lasting legacy beyond the tinamous. Spores are much smaller sized than seeds, and they can quickly grow in a moist location. They can colonize an area quickly, but it still takes time.

The researchers say that only a handful of modern bird types were actually around prior to the asteroid's arrival, including the ancient ancestors of chickens and ducks.

A new study published Thursday in the journal Science has produced hard data to support that global warming hypothesis, and it may have unnerving implications for the world we live in today.

Studying whole paleoecosystems shows how life on Earth has evolved through all the trials and tribulations of the past, Dunn said in an email. This line of inquiry also led to the conclusion that, after the K-Pg event, the ancestors of modern birds had their feet on the ground.

"We basically have to go very carefully looking at layer by layer until we find a very characteristic layer that is red in color. It's possible that, if this sort of logging continues unabated, it will leave an enduring signature on the advancement of birdlife".

Dunn added that "By studying this event, we learn about what happened to biodiversity in the past following destruction of Earth's ecosystems and how long it took for biodiversity to recover". On a human time-scale, healing is long undoubtedly. "It's a much closer natural experiment to what we are doing today".

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