What was the main threat to biodiversity in Hawaii and other islands in the Pacific and Indian oceans until recently?

* Hướng dẫn giải

Dẫn chứng: In Hawaii more than half of the native birds are now gone – some 50 species. Such carnage has taken place all across the island communities of the Pacific and Indian oceans. While many species were hunted to extinction, others simply succumbed to the “introduced predators’ that humans brought with them: the cat, the dog, the pig, and the rat.