Palau and Redonda show islands recover fast after rats removed

The Story in Brief

Removing invasive rats from two islands has triggered remarkably fast ecological recoveries, according to separate studies. On Palau’s Ulong Island, fish biomass jumped 183% and leaf nitrogen rose 80% within one year of rat eradication, as seabirds returned and carried nutrients from land to sea. On Redonda in the Caribbean, six thousand rats and all goats were removed by 2017. Vegetation cover increased more than 20-fold, the endemic ground lizard population rose eightfold, and plant species went from 17 to nearly 90. Both studies show measurable change within months to two years, far faster than scientists expected.

The Ulong project, led by Island Conservation and Scripps Institution, is the first experimental study to prove that removing rodents restores seabird-driven nutrient flow to reefs. Redonda’s recovery, led by Antigua and Barbuda’s Environmental Awareness Group, shows how goats and rats together had stripped a volcanic island bare. Conservationists did not replant trees; they simply removed the invaders and let nature rebuild itself.