Pre Ice Age, the North was all flowers

Illustration: Illustratsioon: Mauricio Anton / Nature

Before the last glacial period hit, mammoths were strolling meadows abloom with pasqueflowers, cowslips and forget-me-nots, shows a fresh research published in the latest edition of the renowned Nature science magazine, with Estonians among its authors. The dying out of said plants, during Ice Age, may have brought about the demise of the large mammals.

«Poetically, this has been called the mammoth steppe,» says University of Tartu plant ecology professor Martin Zobel regarding the environment where mammoths toddled along, in their days. «Earlier, they assumed it was like the Ukrainian steppe, with grasses up to one’s breast.» That was based, mainly, on pollen-research.

A totally different picture emerges, however, should one – instead of pollen – undertake to study plant DNA preserved in the soil. In Siberia and Alaska, the study group took permafrost samples in 21 spots, aged up to tens of thousands of years, analysing DNA found therein. In addition to that, DNA was also extracted from the droppings of some large animals of the distant times.

The article, leading authors of which also include the university of Tartu research fellow John Davison and senior research fellow Mari Moora, did indeed reveal that the current understanding of ancient Arctic ecosystem is not true. Instead of grasses and sedge, a large part of the 50,000-years-old vegetation contained herbal life with a much wider leaves, including an abundance of flowers.

«Prairie pasqueflower – a very beautiful flower with a big blossom, cowslips, forget-me-nots of various kinds, buttercup – these all were also present in the Arctic,» lists Ms Moora, «picking» the ones we now know best.  

In areas observed, the flora preceding the Last Glacial Maximum, was much richer in species than presently; however, pollen-research never revealed that. «Grasses emit much pollen, being pollinated by wind. Flowers emit less, being pollinated by insects,» explains Ms Moora.

In the work-group, Mr Zobel, Mr Davison and Ms Moora were tasked with analysing 15 million gene sequences, by these recreating a picture of the plant life back then.

In addition to mammoths, the times also featured the hairy rhino and archaic horse; these and the plant-life were related to each other, as pointed out by Mr Zobel. «These plants were nutritious fodder for the animals, the activities of animals, in turn, enhanced their growth and spread.»

As the last Ice Age peaked, at about 20,000 years ago, with temperatures the coolest and glaciers reaching the furthest, the Arctic ecosystem underwent change – as clearly supported by the samples.

Wide-leaved herbs disappeared, and never returned even when temperatures rose to earlier levels. «Other species replaced them, not linked to the former ones,» notes Ms Moora.

This, the scientists suspect, lead to the dying out of large grass-eaters, as mammoth and the hairy rhinoceros. «According to the earlier theory, people killed all mammoths, wherefore plantlife changed and tundra advanced,» says Mr Zobel. «It’s obvious now that mammoths died out for natural processes, like plants to eat disappearing due to climate cooling.»

This, says Mr Zobel, is another lesson to those that try to forecast future ecosystems. «We see how entire ecosystem changes, the chain of links turned upside down. 50,000 years ago, no modeller could have predicted what kind of an ecosystem would be dominant after Ice Age as it gets as warm again as before,» noted the scientist.