By Tara John
July 28, 2016

CHINA

Chairman Mao Zedong’s 1958 campaign to eliminate “four pests,” including sparrows, disastrously tipped the ecological balance. Predator-free locusts destroyed crops, exacerbating a national famine that killed millions.

AUSTRALIA

Bounties offered by the government of Tasmania for the Tasmanian tiger played a part in causing the eventual extinction of this apex predator in 1936. The marsupial had been considered a pest in the Australian island-state.

U.S.

A 20th century federal extermination program nearly killed all gray wolves in the U.S. Their 1995 reintroduction to Yellowstone National Park stopped elk from overgrazing and increased biodiversity.

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This appears in the August 08, 2016 issue of TIME.

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