David Pate

The degree to which humans are a keystone species is proportional to the level of technologial developement, but with a twist at the end. In prehistoric times, humans were not keystone species. Their effect on the environment was limited due to the diverse nature of an omnivore. Then, as the humans' ability to use technology grew, humans started to greatly effect the enviroment with things like dams, pollution, farmland, and urban developement. This would certainly qualify humans as a keystone species. But now, by using new techonology to be more efficient, humans are able to do more with less, and our total biomass is increasing, making our effect on the enviroment more proportional to our biomass. So the degree to which humans are a keystone species is decreasing because our total biomass is increasing and our effect is decreasing (or will be soon) due to conservation efforts.