MAP: What the Earth would be like if humans never existed
File image.
Digital Reporter
Tuesday, August 25, 2015, 1:53 PM - Rhinos and elephants in Europe? Canada's sub-Arctic teeming with large animals?
It could have happened -- if mankind hadn't gotten in the way.
That's finding of a new study published by Aarhus University in Denmark. The researchers extrapolated the numbers of species of mammals weighing 45 kg or more in non-human world, and compared it to current distribution of species of that size.
According to them, here's how Earth would look if humans had never arrived to reduce animal populations:
And here's how Earth's mammal distribution looks today:
It's a totally different world. Today, only the interior of Africa looks like it supports substantial numbers of large mammals. In Canada, the mountains of the west are the last refuge for large concentrations of animals like wolves, bears and moose, with just stragglers hanging on elsewhere, if at all.
But in the alternate reality presented by the study, mammals aside from humans thrive. Europe, Asia and the Siberian steppes are home to large concentrations of species. In the Americas, central South America and the western plans of North America are hotspots, with plenty of species elsewhere, reaching as high up as the sub-Arctic in Canada.
One of the report's authors, Søren Faurby, says the researchers aren't sure exactly why the diversity in North America is so much higher than in Europe.
"But it seems likely that it is related to a higher diversity in animal groups in North America, which contains a mix of groups from the formerly isolated South America, from Eurasia, and lineages that developed in North America," Faurby told The Weather Network. "It is often thought that animals compete more with close relatives. The more distantly related fauna in North America may therefore potentially support more species in similar climate than an area with similar climate in Africa which consists almost entirely of closely related antelopes."
Faurby says for ranges of recently declined species, the historic range was used, but for species that experienced an earlier decline, they looked at climate conditions like winter and early average temperatures and annual precipitation, based on the current climate.
For long-extinct species, the modeled their "alternate" presence based on the distribution of species they used to exist with.
"By doing this we are indirectly using climate to estimate the range, since climatic conditions are limiting the range of the extant species whose range we use to estimate potential range of the extinct species," Faurby says.
Faurby and his colleagues hope the new data will help in conservation efforts worldwide.
The study was published in the journal Diversity and Distributions.
SOURCE: Aarhus University
