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An invasive frog in the Marshall Islands is displacing native species and threatening local ecosystems

Biologists from The University of Texas at Arlington are the first to discover an invasive frog—the greenhouse frog—in the Marshall Islands, a sprawling Pacific nation of volcanic islands and coral atolls located roughly halfway between Hawaii and Australia.

"Originally from the Caribbean, these frogs are notorious for expanding their habitat by hitching rides in soil, potted plants and agricultural materials," said Samuel Fisher, a UT Arlington graduate student working under the guidance of biology Professor Matthew Fujita. "We mostly found the frogs on Laura Island, one of the larger islands and home to the main airport, but we confirmed them on other islands as well."

The greenhouse frog isn't the only introduced species raising concerns. The UTA team also studied the green anole, a lizard native to Texas and Oklahoma and commonly found across the southeastern United States. Possibly introduced from Hawaii, the green anole has become widespread on the Marshall Islands' main island. Researchers found evidence that it may be eliminating the emerald tree skink, a native lizard species.

"The lack of skinks suggests that imported anoles may be outcompeting native species, which could have ripple effects on the islands' ecosystems," UTA's Dr. Fujita said. "Although these frogs and lizards may seem harmless, they can cause major ecological disruptions by displacing native species, altering food webs and potentially spreading diseases—to both animals and humans."

Working with local partners like the Marshall Islands' Ministry of Natural Resources and Commerce Quarantine Division and the Secretariat of the Pacific Regional Environment Program, the UTA team collaborated with scientists from the U.S. Geological Survey to study how the region's landscape has changed over the past 40 years. Their research included an analysis of shifts in island size, shape, vegetation, and critically, the makeup of reptiles and amphibians.

In addition to their field research, the UTA team provided biosecurity training to local officials to support early detection and control of invasive species. They also worked with partner agencies such as the U.S. Fish and Wildlife Service and the Hawaii Department of Agriculture to encourage awareness and strengthen regional responses to invasive species.

"Researching invasive species is incredibly important for all regions, but islands are especially vulnerable, as they often have limited natural predators to balance the threat of new organisms," Fisher said. "Understanding their impact helps us mitigate potential economic disruptions—from agriculture and livestock to the beaches and wildlife that draw tourism."