If you have spent a little time outdoors lately you likely know that invasive species are have been entering our ecosystem for some time. 

Below is a great article about the history of invasive species, their role on economies, and the relationship to current as well as historic practices of food management. 

http://www.nytimes.com/2011/08/30/science/30tierney.html#?wtoeid=growl1_r1_v4