true TC, but mans been manipulating the natural balance since gods dog died. Usual based upon what we believe to be the most "valuable" creature/environment etc. Grouse moors are not a natural environmental balance, but they are managed for "the greater good". Question is, where do you draw the line?
Thats the problem, whenever man has a hand in anything it is always for his advantage. Sometimes though they will pick the weakest species and manage the environment for their benefit exclusively, to the detriment of other species.
TC