A change in plant life could be responsible for the demise of mammals and other tundra animals 10,000 years ago.
Researchers used new DNA technology to determine that a switch from "protein-rich herbs" to "less nutritious grass" could have contributed to the animals' extinction, a Lund University news release reported.
The team looked at 50,000 years' worth of vegetation history in Arctic regions of Canada, Russia, and Alaska. Between 18,000 and 25,000 the majority of these regions were covered in ice but there were also ice-free areas containing the mammoth steppe. These areas hosted animals such as "mammoth, woolly rhinoceros, steppe bison, horse," the news release reported.
Most of these animals mysteriously disappeared about 10,000 years ago. In order to determine why this extinction occurred Lund researchers and 30 other teams from around the world conducted a survey that looked at what the animals ate.
"My role has been to oversee the collection of a large number of soil samples which are then analysed by biologists in laboratories," Lund University geology professor Per Möller said in the news release.
The researcher took a number of soil samples from Arctic Siberia over the course of 16 years. The research team then analyzed plant DNA residue and were able to see some of the plant life that grew on the mammoth steppe.
The team also looked at the stomach contents of eight large mammoths that had been preserved in ice. They found the steppe was dominated by herbs instead of grass during the most recent ice age. Once the ice age ended and humid interglacial period began the plant life changed for the worse.
"The herbs then became less dominant, and grass took over," Per Möller said.
The less-nutritious vegetation could have harmed the survival rates of a number of animals in the region and contributed to their demise.
In the past researchers believed the steppe was primarily covered by grass by looking at pollen samples; the DNA evidence paints a different picture.
"We will have to re-evaluate a lot of old truths," Per Möller said.
