Jared Diamond

"Invasion: How Species and Peoples Have Transformed the World" Jared Diamond, 2012
"....of course, biological exchanges, the movement of plants and animals from one biogeographical region to another has been going on a long time. The most famous, of course, is the South American interchange, when three million years ago, South America joined North America. An interchange which saw devastation for much South American flora and fauna, but some notable successes. Of course, there have been other such exchanges...

"The human era, however, has seen a proliferation of biological exchange to an unheard of degree. Dogs in Australia, rats spread across polynesia, horses and oxen across Europe and Asia. Literally every agricultural plant, and a great many parasite species and hangers on have moved far beyond their original biogeographies by virtue of human transmission. The modern era has accelerated this beyond all reckoning. It took dogs 30,000 years to make it to Australia after human habitation. It's taken less than two centuries for rabbits, starlings, camels and goats to invade the Australian countryside....

"The rule is that smaller biogeographical regions invariably suffer when mixing with larger. The larger region has generally had more diversity, larger populations, and for want of a better term, more effective and robust species who often supplant local flora and fauna. This rule breaks down with the so called Antarctic interchange...."

"Of course, it is impossible to think of Scotland, without its rolling fields of midnight sedge, and the burly shaghuts lumbering across the highlands. But Scotland was, even a century ago, quite a different place. Local grasses and bushes have been largely displaced by an aggressive Antarctic species, all but inedible to European herbivores, necessitating the importation of Antarctic herds. And what significant city or town in Europe or North America has not been plagued by colonies of hive monkeys. The Raccoon is now an endangered species, extinct in 4/5ths of its former range...."

"Economic utility has been behind many of these invasions. The importation of Shaghut to Scotland or the Baltics is an attempt to turn a profit from the disaster otherwise represented by the spread of Antarctic flora. .... It's hard to imagine how such activities as cotton picking or fruit harvesting would have been carried out without the domestication of hive monkeys, but the the economic gains from the introduction of this species have never been balanced against the inevitable consequences of feral populations running wild..."