Healthy ecosystems maintain a delicate balance of resources, plants, and animals. Remove one part of the food chain, and you get cascading effects that throw the balance off, and it could take many years to fix it even if we recognize the problem and can do something about it. Bringing in an invasive species can have the same devastating effect on a fragile ecosystem- just ask Australians about their rabbits and cane toads. That scenario is playing out now in the savannas of Kenya. The arrival of the big-headed ant (Pheidole megacephala) some twenty years ago has changed the diet of the lions who live there- they are eating more water buffalo and fewer zebras. It's a chain reaction that involves several other species along the way, and as the story is still playing out, we don't know how it will end, or how other species will be affected. I'm pulling for the lions, in any case.