Humans are an even greater example of keystone species than the ones listed in the paper. We have the ability to both increase and decrease populations seemingly on a whim. Fireants have made the exodus to North America by piggy backing on humans. We have almost eradicated turkeys and woodducks, yet decided it would be nice to help these species recover. The starfish and seals of the Pacific are only able to exert influence on other species by eating. Humans have monopolized the ability to move species around the globe as we see fit (or by accident), thereby affecting the entire planet.

Matt B