Large non-native species can increase biodiversity

Buffaloes foraging in the Welsh marshes Picture: Joan Gravel/Alamy
Moose and buffaloes often nibble off and spoil plants, so it may seem a bad thing for these large animals to flee from their native areas and invade other areas.
, however, they seem to have benefits in "roaming" on Earth.
largely because of the introduction of humans, wild animals like camels, moose, buffaloes and donkeys - known as "mega-animals" because of their size - live in large numbers outside their native areas. Often, ecologists treat these outsiders coldly, assuming they cause damage. Conservation biologists, for example, have been calling for the removal of wild horses that have come to the United States with Europeans over the past 500 years from certain areas.
, says Eric Lundgren of Arizona State University. He believes it is becoming increasingly difficult to figure out where such animals "belong". Lundgren and colleagues studied the whereabouts of 76 large plant-eating mammals. They found that 22 species had large populations outside their native areas, while 10 species were extinct or could never return to their "home" homes. For example, there are estimated to be 5 million wild donkeys worldwide, but only a few hundred of their pre-domesticated ancestors, the African wild donkeys.
, the team believes that new visitors should be welcomed as restorers of nature. They describe it as "the re-wilding of the Anthods". On the one hand, the populations introduced are beneficial to biodiversity. Killing them may put other species at risk. They can also assume useful ecological services. The results were published
Journal.
sometimes, these benefits are intentional. Romanian buffaloes eat marshes in a nature reserve in Wales, England, maintaining an ecological balance in open water. Similarly, giant tortoises from the island of Aldabora were placed in Mauritius to replace the extinct species and spread the seeds of local trees. (Source: Science Network Xu Xu)