MANHATTAN, Kan. -- A recent study in the journal Nature finds that nearly 50,000 years ago during the ice age, the landscape was not as drab as once thought -- it was filled with colorful wildflowers. These wildflowers helped sustain woolly mammoths and other giant grazing animals.
The study, "Fifty thousand years of Arctic vegetation and megafauna diet," included Joseph Craine, assistant professor in the Division of Biology at Kansas State University. It was led by 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.
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."
The study challenges the view that the arctic landscape in the ice age was largely grasslands.
"Part of the scientific debate is knowing what the past looked like," Craine said. "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."
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."
Journal
Nature