These invasions, both the naturally occurring and those dependent on human assistance, are likely to continue indefinitely. Quarantine and massive chemical campaigns are only extremely expensive ways of buying time. We are faced, according to Dr. Elton, “with a life-and-death need not just to find new technological means of suppressing this plant or that animal”; instead we need the basic knowledge of animal populations and their relations to their surroundings that will “promote an even balance and damp down the explosive power of outbreaks and new invasions.”
