Humans are thought to be responsible for a large number of environmental problems, ranging from global warming to ozonedepletion. That is not in doubt, however, is the devastating effect 1humans are having on the animals and plants of the planet. Currently, an estimated 50,000 species become extinct eachyear. If this takes on, the impact on all living creatures is likely to 2be profound. All species depend in some way each other to survive. 3If you remove one species from this very complex web of interrelationships, you have very little idea about the knock-oneffects on the ecosystem. However, if you lose a key species, you 4might cause a whole flood of other extinctions. The most complicating matter is the fact in that there is no 5obvious solution to the problem. Unlike global warming and ozonedepletion—which, if the political will is there, could be reduced by 6cutting gas emissions—preserving bio-diversity remains an intractable problem. The late idea is " sustainable management" , which involves 7using any species for human beings' benefit, provide enough 8individuals of that species are left alive to ensure its continued existence. Sustainable management is seen as a practical andeconomic way of protecting species from extinction. Instead of 9depending on largely ineffective laws against illegal hunting, it gives local people a good economic reason to preserve plants and animals. This sounds like a sensible strategy, but it remains to be seen whether it will work. With corruption popular in many developing countries, some observers are suspicious that the money willactually reach people it is intended for. Others wonder how effective 10the locals will be at stopping illegal hunters.