Climate: DNA study offers clues on ice age vegetation

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Ice age flora was more diverse than previously thought, according to a new study.

Where the woolly mammoths roamed …

By Summit Voice

FRISCO — The last ice age may not have been as drab and dull as long thought. Instead, some areas may have sustained a diverse vegetation cover, including colorful wildflowers, according to new research published in the journal Nature.

Those lush meadows helped sustain woolly mammoths and other giant grazing animals, according to the study, recently published in the journal Nature.

The study was led  the Centre for GeoGenetics at the University of Copenhagen and was a collaboration of more than 25 academic institutions and research laboratories from around the world. It challenges the view that the arctic landscape during the ice age was largely grasslands.

“Part of the scientific debate is knowing what the past looked like,” said Joseph Craine, assistant professor in the Division of Biology at Kansas State University. “There have always been debates about how a region that’s so cold could have supported animals that were so large. Mammoths were huge and lived on these largely barren landscapes. Now we know that they were spending a lot of time eating wildflowers, which have a lot more protein in them than grasses, which means that they could support larger animals.”

The study looked at 50,000 years of arctic vegetation history to understand how fauna had changed with animals and humans.

Historically, the belief is that the ice age’s landscape was covered by largely grass-dominated systems — called steppe. These grasses were replaced by mosses and other boggy vegetation when the ice age ended nearly 10,000 years ago, Craine said.

For the study, researchers visited museums in Alaska, Canada, Norway and Russia to collect DNA samples from inside the gut of frozen mammoths, bison, horses and rhinoceros that lived in the ice age.

Molecular techniques were used to look for plant DNA in each ancient animal’s digestive tract. Plant DNA was then sequenced and reconstructed to differentiate wildflowers from grasses.

“Once the gut contents and soils started getting sequenced, they began finding lots more wildflowers than before,” Craine said. “Nearly half of the digested plants were wildflowers. So, rather than having this really grassy, dull system like we believe existed, it suddenly was one that was very colorful.”

Craine helped interpret data and the consequences of losing bison and other grazing animals over thousands of years in parts of the world.

Although the findings reframe 50,000 years of the past, they also are applicable to predicting the future, Craine said.

Animals’ grazing and climate changes stressed and eventually reshaped the vegetation in the tundra from wildflowers and grasses to moss and marshes, he said.

“The work is important because we can use the past to help us predict the future,” Craine said. “But the work really makes us reevaluate how well we understand the diets of modern animals. If we misunderstood what bison and mammoths ate 15,000 years ago, maybe we should look more closely at what bison and elephants eat today. We just might find new surprises.”

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