What happened to the famous Ice Age giants? A study now sheds light on why the representatives of the megafauna once disappeared from the landscapes of Central Europe: Sediment cores from volcanic lakes in the Eifel illustrate the decisive role of vegetation changes for the populations of large mammals over the past 60,000 years. With the increasingly dense forest cover in the region, the era of the giants finally came to an end around 11,000 years ago. However, the scientists say that hunting by humans does not seem to have played a role.
Mammoth, woolly rhinoceros, giant deer...: Impressive heavyweights once shaped Europe's Ice Age wildlife that have now disappeared. It is unclear which factors led to the extinction of the megafauna. However, climate changes, increasing hunting by immigrant humans, and changes in the landscape are already being taken into account. In order to gain further insight into this story, the scientists led by Frank Sirocko from the Johannes Gutenberg University of Mainz examined sediment cores from Lake Holzmaar and the dry maar of Auel in the Vulkaneifel. As they explain, the layered deposits provide insight that goes back as far as 60,000 years. The analyzes focused on traces of plant pollen and fungal spores in the layers. As the researchers explain, studies of pollen characteristics can map the composition of vegetation at different times. The fungal spores, on the other hand, allow conclusions to be drawn about the presence of large mammals. Because it is known that certain molds only grow on the dung of large herbivores.
The living environment reflected in pollen and spores
As the team reports, the results of the investigation showed that the Eifel was characterized by a spruce forest between 60,000 and 48,000 years ago. Subsequently, in the course of several cold snaps, the landscape slowly transformed into an open forest steppe. This form of vegetation then developed about 30,000 years ago via a forest-tundra into a grass-covered Ice Age steppe. About 13,000 years ago, however, the forest began to spread again and finally reached a high density.
The results of the examination of the spores of the typical faecal fungi of large mammals showed that large mammals lived in the Eifel landscape until around 11,000 years ago. While megafauna were also present during the warmer interstadials, they reached significantly higher numbers during the colder periods. Decreases in the warmer times were apparently associated with the increase in the tree population.
Based on fossil finds from caves in Belgium and in the Rhine Valley, the researchers assume that mammoths, woolly rhinos, bison, horses, reindeer and giant deer shaped the megafauna in the cold phases. As the results of the study show, these large animals only began to leave the landscape around 13,000 years ago when birch forests began to spread. For about 11,000 years, the herds of large mammals have not been represented at all. Because from this time dense forests covered the Eifel, show the results. Apparently, the animals found no further opportunities to live in this landscape.
The forest brought the giants in the Eifel from
The study results provide an indication that the development of the forests was the main reason for the decline and the eventual disappearance of the large mammals in Central Europe, the researchers conclude. "With increasing forest cover, the large herbivores probably lost their main food, namely grass," explains Sirocko. The results of the investigation also show that the climate changes alone were probably not the decisive factor for the decline. According to the results, volcanism in the Eifel has hardly affected the population of megafauna in the region over the past 60,000 years.
But what about the human factor? Megafauna populations appear not to have been significantly affected by the arrival of our ancestors 43,000 years ago, the researchers say. According to them, the identified times of large occurrences of large mammals often coincide with known phases of high human presence in the region. They were probably also attracted by the large numbers of animals. “We see this most clearly about 15,000 years ago. At that time, the highest population of large mammals coincided with the archaeologically proven presence of hunters in the Rhine Valley,” says Sirocko.
According to the researchers, the fact that Ice Age humans and large mammals apparently coexisted without any problems for several millennia proves that the hunters probably did not put a significant strain on the animal populations. The Eifelmaar sediments therefore do not provide any evidence for the so-called "overkill hypothesis", according to which humans played an important role in the decline of the megafauna. At least there, the forest apparently put an end to ice age travel.
Source: Johannes Gutenberg University Mainz, specialist article: Scientific Reports, doi: 10.1038/s41598-022-22464-x