Human Movement and Exotic Species
In the September 2011 issue of WIRED magazine, Mario Aguilar discusses the ecological impact of Columbus’ voyage to the Americas. Aguilar garnishes his information from a book written by Charles C. Mann titled; 1493. The article explains how Columbus’s discovery of the New World obviously altered human civilizations, yet dramatically affected a multitude of plant and animal species as well. In this article, Aguilar quotes Mann as saying in his book; “Things are connected in ways that you would never expect.”
Four examples are given, regarding species that were influenced by the movement of humans around the globe.
The first example is the African Plantain, which has always been plagued by the scale, a species of insect. While in Africa, the Plantain was able to thrive despite the infestation of the scale because other species in Africa preyed on the scale, helping to reduce its population. But, when the Plantains were brought to the Americas, the scale insects not only killed off the plantain crops, but also helped to grow the fire ant population who fed on the sugary excrement of the scale insects.
Another example is the Orchids that were once a thriving species in the moisture rich jungles of Southern China. However, when rubber plants were brought to South East Asia from the Amazon, the rubber plants drank up so much moisture that the morning mist no longer existed, and the orchids began to die off.
The third example of species influence by human manipulation is the movement of earthworms which originally tilled the soil for English farmers. Yet when the earthworms were brought to the United States, they disrupted the nutrient absorbing fungi on the roots of sugar maple trees, ultimately leading to a decline in the sugar maple tree populations.
Interestingly, although the earthworms caused a decline in sugar maple trees, they aerated the ground so well that maize crops were able to grow year round.
The last species mentioned in this article is the Colorado potato beetle which was transported to America in the manes of horses. This insect has afflicted potato crops, not only in America, but worldwide.
If you know of any other species that humans have moved around the globe please leave a comment!