> The way I understand it there are no extras in nature. There are no "extras" in the sense if you want nothing at all to change, you need to keep everything,

> The way I understand it there are no extras in nature. There are no "extras" in the sense if you want nothing at all to change, you need to keep everything, but I don't think ecological niches go unfilled for long. The world would be pretty fragile if the loss of any single species completely destroyed an ecosystem.