It's all a vast complex interconnected system.. What if, for example, a totally fictional madeup example, Eagles really liked to chow down on Grouse, and all follow them into that smaller area to stay close to their favorite treat.. In that scenario removing the habitat for the Grouse causes the eagle to become rare everywhere else! Well except for canada, several eagles nest outside the window of this house I am housesitting for a few weeks.

Obviously that's all gross over-simplification, but eh..

Isn't there a way to get the oil without ripping apart the countryside?