Pleistocene re-wilding refers to reintroducing animals that disappeared from the North American continent 13,000 years ago, particularly its megafauna (Donlan 913). The plan by conservationists is to promote the restoration of large wild vertebrates into North America, which they say will otherwise become overrun with 'pests and weeds' which they identify as rats and dandelions. The animals would be reintroduced in a series of carefully managed ecosystem manipulation, and they would use closely-related species to those which are extinct, and change the emphasis of conservation biology from preserving animals from extinction to actively restoring natural processes.
The reasoning behind the project is fourfold: first, that there is no longer such a thing as a pristine ecosystem since human activities have pervaded every such system; secondly, they say that environmentalists are usually portrayed as conveyors of 'doom and gloom' - maybe this would improve their image; thirdly, certain areas of the United States, particularly the Great Plains, are losing human populations; and fourthly, humans were no doubt responsible for the demise of the large vertebrates from North America during the late Pleistocene period, and still today are responsible for the extinction of more and more species with their advancing population of their ecosystems (Donlan 913). They believe this means we have an ethical responsibility to address these problems, and re-wilding is a way of doing so.
From an ecological and evolutionary standpoint, reintroducing these large animal species is important, not only because of the near extinction of many of the animals in Africa, but because they shaped the evolution of the smaller animals (Donlan 913). As an example, they believe the presence of the American cheetah (Acinonyx trumani) was responsible for the development of great speed by the pronghorn (Antilocapra americana), which evolved over four million ye...