When the Polynesians arrived in these islands they found a wonderland where virtually every ecosystem on earth was present. Wet or dry, hot or cold, lush or barren. Whatever one sought one could find. It was inevitable that the newcomers would have an impact on this pristine environment as their numbers grew. Dr. Sam Gon of The Nature Conservancy has plotted the early human footprint on the islands.
“Even though we had hundreds of thousands of people thriving in this archipelago before Western contact, the majority of them were down along the coast and covered only about 15 percent of total land area. Hundreds of thousands of people have no way to have zero impact on the land. You have to have fires to cook your food, you have to have wood to build homes, you need agricultural areas.”
And yet, says Gon, with the exception of the kukui tree, the plants the Polynesians brought were not invasive. So when humans moved out of an area, it would revert to its natural state. The animals that arrived with the Polynesians were more problematic, none more so than an introduction that was likely unintended but disastrous: the rat. Rats multiplied exponentially and feasted on plant seeds and the eggs of birds.
“Rats had a huge role to play in the extinction of many of the ground-nesting, flightless birds. And the timing of their disappearance matches shortly after the appearance of a human presence in the islands."