<P> Possibly one of the best examples of an ecosystem fundamentally modified by human activity can be observed as a consequence of the Australian Aboriginal practice of "Fire - stick farming". The legacy of this practice over long periods has resulted in forests being converted to grasslands capable of sustaining larger populations of faunal prey, particularly in the northern and western regions of the continent . So thorough has been the effect of these deliberate regular burnings that many plant and tree species from affected regions have now completely adapted to the annual fire regime in that they require the passage of a fire before their seeds will even germinate . </P> <P> Despite being discredited among ecologists, the theory is widely held to be true by the public . At least in Midwestern America, the "balance of nature" idea was shown to be widely held by both science majors and the general student population . In a study at the University of Patras, educational sciences students were asked to reason about the future of ecosystems which suffered human - driven disturbances . Subjects agreed that it was very likely for the ecosystems to fully recover their initial state, referring to either a' recovery process' which restores the initial' balance', or specific' recovery mechanisms' as an ecosystems' inherent characteristic . </P>

Why should the balance in the food chain be maintained