Forty percent of the world’s plants and animals rely on just five percent of the Earth’s land area - islands. Of the 245 recorded animal extinctions since 1500, 80 percent were on islands - usually because of invasive species.
Earlier this year, the U.S. Fish and Wildlife Service strengthened its partnership with the nonprofit Island Conservation to remove invasive species from islands, one of the most effective ways to save endangered species and restore ecosystems.
The Memorandum of Understanding signed in April “promotes an integrated and coordinated approach to invasive species removal. Working together, we will ensure that the best available science and management practices are updated and employed for future island invasive species removals,” says U.S. Fish and Wildlife Service Director Dan Ashe.
The Service manages islands in over 200 national wildlife refuges, affecting as many as 161 threatened and endangered species.
Refuges have already removed invasive species from islands. On Palmyra Atoll in the Pacific Ocean, rats devoured the seeds and seedlings of native trees that provided nesting sites for the red-footed booby. In 2011, the Service, Island Conservation and The Nature Conservancy collaborated to remove the rats. As a result, there has been a 271 percent increase in native seedlings. The restoration also allowed three new land crab species to return to the island.
Rats have also been eradicated from Midway Atoll in the South Pacific and Hawadax Island in Alaska, part of Alaska Maritime National Wildlife Refuge and once so infested with the invasives that it was called as Rat Island.
Desecheo National Wildlife Refuge in Puerto Rico will receive $1 million this fiscal year for a second try at eradicating black rats and restoring the native island ecosystem. On Johnston Atoll National Wildlife Refuge, part of the Pacific Remote Islands Marine National Monument, the problem is invasive crazy yellow ants, which overwhelm indigenous wildlife by spraying corrosive acid. Since 2010, small groups of volunteer biologists – in Crazy Ant Strike Teams -- have made progress in controlling the ants.
On Laysan Island in Hawaii, the problem was invasive rabbits. Since they were eradicated in 2011, the endangered Nihoa millerbird has increased from 24 to 161 birds. Unfortunately, the rabbits were not removed soon enough to save the Laysan rail or honey creeper.
See Service Director Dan Ashe’s blog: Partnership to Prevent Extinctions Strengthened
Distinctive island refuges featured in Refuge Update November December 2015