Everything needs everything else, they say, to make nature balance. If that were right, it might explain why the six orchid species should be saved. We could pour weedkiller on all the orchids in Australia and do no ecological damage to the rest of the continent s biology. Natural biological systems are hardly ever stable and balanced anyway. Everything goes along steadily for a time, then boom - the system falls apart and simplifies for no visible reason.
Diverse systems are usually more unstable than the less diverse ones.
Not to mention the timeless grass of a salt marsh. In other words, there s no biological law that says we have to save the orchids because they add diversity, and that added diversity makes the biological world more stable. But back to the imperilled orchids. Orchids are at the top of the chain, said Dr Dixon. They use the system, like us.