Palmyra AtollKEVIN LAFFERTYOne thousand miles south of Hawaii, the Palmyra Atoll, a horseshoe-shaped chain of islets, is about as isolated as you can imagine, says Erin Mordecai, a biologist at Stanford University who has visited the islets to conduct ecology research. “It’s really, really remote and has never had a native human population,” she says. Year-round, the population varies between approximately five and 30 people—generally, scientific researchers and Nature Conservancy staff.
But the atoll is far from unspoiled, Mordecai continues. “The most human impact it’s had was during World War II when there were about 2,400 troops.” Considering the brevity of the soldiers’ inhabitation, the repercussions were immense. “They built airstrips on some of the islands. There’s still metal and debris that they left behind.” They also brought rats and mosquitoes, neither of which is native to the atoll. There are in fact no native mammals and only a few native insects.
With no predators and plenty of food, the rat population exploded. In 2011, it was estimated to have reached 40,000. “There’s not a lot of land . . . [so] they were everywhere,” says wildlife refuge manager Stefan Kropidlowski of the US Fish and ...