A conservation experiment conducted on Ulong Island in Palau has revealed that ecosystems can recover much faster than previously believed after the removal of invasive rats.

The project, led by the nonprofit organization Island Conservation, compared Ulong Island, where rats were eradicated, with nearby Ngeruktabel Island, where rats remained as a control site.

Before the eradication effort, researchers collected baseline data on biodiversity, including bird activity, soil conditions, fish biomass, and coral reef health.One year after the rats were removed, scientists observed significant ecological improvements.

Seabird populations increased sharply, with bridled tern detections rising by 286% and brown noddy and white tern activity increasing by approximately 50%.Rats had previously preyed on seabird eggs and chicks, suppressing nesting populations across the island.The return of seabirds appears to have triggered broader ecosystem benefits.Seabirds transport nutrients from the ocean to land through their feeding activities, enriching island soils.

These nutrients eventually flow back into surrounding waters, supporting marine productivity in what scientists describe as a 'circular seabird economy.' Researchers documented substantial increases in fish biomass around Ulong Island, including a 183% increase at one monitoring location.Early evidence also suggests that nutrient enrichment is helping support coral reef growth and productivity.Scientists involved in the project had expected such ecological recovery to take decades, making the rapid improvements particularly noteworthy.

The findings provide experimental evidence that removing invasive species from islands can generate benefits for both terrestrial and marine ecosystems within a relatively short period.Researchers believe the results offer hope for broader restoration efforts throughout Palau's Rock Islands and other island ecosystems worldwide.