Science Center Objects

Invasive plants and animals can cause havoc in tropical island ecosystems, because many organisms that have evolved on islands have lost the ability to combat organisms arriving from the continents for reasons as varied as changes in immunity, life history, or behaviors. Early detection and intervention are key aspects dictating whether or not invasive organisms become established.

Surveillance of invasive species

In addition to plants and animals, pathogens can also be invasive, and early detection depends on good surveillance.  As part of our routine surveillance activities to monitor health of terrestrial and marine organisms, we have detected new incursions and phenomena that have had significant management implications.  For instance, we helped document mouse predation on Laysan albatross on Midway Atoll National Wildlife.  Currently, the refuge is contemplating methods to eliminate mice. 

Corallimorph infestation on coral reef

Corallimorph infestation at a shipwreck site in Palmyra Atoll National Wildlife Refuge. (Credit: Thierry Work, USGS. Public domain.)

In another example, we documented an invasive anemone, Corallimorph, at Palmyra Atoll National Wildlife Refuge.  Corallimorphs, or CM, can rapidly spread in coral reefs that have been degraded by environmental or man-made disturbances. At the Palmyra Atoll NWR in the Central Pacific, researchers found CM expanding and smothering otherwise pristine coral reefs in an area near a shipwreck. Starting in 2007, USGS scientists and partners surveyed the CM-infested coral reef before and after removal of the shipwreck. They found that wreckage removal helped reduce the proportion of highly CM-infested areas from 21 percent to 14 percent, marking the first time that shipwreck removal was shown to have beneficial effects for reef recovery from CM.

The scientists then devised additional methods to control CM on a small scale. By exposing CM to chlorine, they found that they could nearly eradicate the organism from small plots of about 100 square feet after several days. These plots remained mostly CM-free for at least 15 months, allowing native organisms such as coralline algae and small corals to regrow. (Work et al. 2018)

Research on invasive species

In collaborations with various institutions such as University of Utah, University of Rhode Island, USFWS, and The Nature Conservancy, we are currently working to devise methods to control continued spread of anemones on coral reefs at Palmyra Atoll NWR.