North American ecosystem shift 6,000 years ago caused by humans

Terraced Farming

I’m not sure if the study referenced in this review has a solid statistical basis or not, but the findings certainly are fascinating. Researchers claim to have found evidence for an abrupt ecosystem shift in North America (!) triggered by the arrival of humans dependent on agriculture . . .

For the past 6,000 years, human beings have been having an extreme effect on the distribution of animals and plants across the globe, some of which had been in place for up to 300 million years, to the point that some species are more segregated from others than they have ever been. A research team from the Evolution of Terrestrial Ecosystems (ETE) program, led by S. Kathleen Lyons, performed a study that looked deeper into plants’ and animals’ distribution across the landscapes of the planet through fossil records.

The shift has been so dramatic that the team discovered that the consequences of a shift like this could usher in a new stage in global evolution equivalent to that of the evolution of complex organisms from single-cell microbes, according to Smithsonian Magazine.

The team decided to focus on locating patterns among plants and animals, filtering out the relationships that could be classified merely as chance. They looked at two types of relationships – pairs and segregations – to find these patterns. Pairs would include animals that occur together, like cheetahs and giraffes, which are often found in the same areas, while segregations would include animals that are not present when another is.

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