Scientists map a world without humans

Researchers have provided the first estimate of how the mammal diversity world map would look like if modern man had never existed.
In a world without humans, most of northern Europe would probably now be home to not only wolves, Eurasian elk (moose) and bears, but also animals such as elephants and rhinoceroses, researchers said.
In a new study, researchers found what the natural worldwide diversity patterns of mammals would be like in the absence of human impacts, based on estimates of the natural distribution of each species according to its ecology, biogeography and the current natural environmental template.
"Northern Europe is far from the only place in which humans have reduced the diversity of mammals - it's a worldwide phenomenon," said Jens-Christian Svenning, from the Department of Bioscience, Aarhus University in Denmark.

The current world map of mammal diversity shows that Africa is virtually the only place with a high diversity of large mammals.
However, the world map constructed by the researchers of the natural diversity of large mammals shows far greater distribution of high large-mammal diversity across most of the world, with particularly high levels in North and South America, areas that are currently relatively poor in large mammals.

"Most safaris today take place in Africa, but under natural circumstances, as many or even more large animals would no doubt have existed in other places, notably parts of the New World such as Texas and neighbouring areas and the region around northern Argentina-Southern Brazil," said lead author Soren Faurby, a postdoctoral fellow at the Department of Bioscience, Aarhus University.

The existence of Africa's many species of mammals is not due to an optimal climate and environment, but rather because it is the only place where they have not yet been eradicated by humans, th researchers said.
The underlying reason includes evolutionary adaptation of large mammals to humans as well as greater pest pressure on human populations in long-inhabited Africa in the past.
Today, there is a particularly large number of mammal species in mountainous areas. This is often interpreted as a consequence of environmental variation, where different species have evolved in deep valleys and high mountains.
"The current high level of biodiversity in mountainous areas is partly due to the fact that the mountains have acted as a refuge for species in relation to hunting and habitat destruction, rather than being a purely natural pattern," Faurby said.

"An example in Europe is the brown bear, which now virtually only live in mountainous regions because it has been exterminated from the more accessible and most often more densely populated lowland areas," Faurby said.
The study was published in the journal Diversity and Distributions.