Seven years ago, Redonda, a volcanic island in the Caribbean Sea, resembled the moon’s surface: a dusty, debris-covered, barren terrain.

The island, which is part of Antigua and Barbuda, had once been mined for guano, seabird excrement used for fertilizer. However, mining operations on Redonda ceased around the start of World War I, and when the miners were gone, they left behind a legacy of rats and goats.

Over the successive decades, the rats and goats stripped Redonda of its vegetation. Rocks and soil slid into the sea, damaging the reefs and seagrass and making it dangerous for anyone to venture onto the island.

Then, in 2016, conservationists began removing the rats and goats to restore the island. They first used a rodenticide to eliminate the rats while not harming other biodiversity. Then, they captured and transported the small population of goats by helicopter off the island, most of whom had been starving due to the lack of food on Redonda.

Once these invasive animals were gone, Redonda transformed faster than anyone could have imagined. Native trees and grasses sprouted back. Seabirds like brown boobies (Sula leucogaster) and red-billed tropicbirds (Phaethon aethereus) recolonized the island. According to conservation experts working to restore Redonda, the population of the critically endangered and endemic Redonda ground dragon (Ameiva atrata) has increased thirteenfold since 2017.

“The island was in such a dreadful state that everyone thought it was going to need an awfully long time to recover,” Jenny Daltry, Caribbean alliance director for the NGOs Re:wild and Fauna & Flora International, told Mongabay. “But we were seeing changes really fast.”

After the successful restoration of Redonda, the government of Antigua and Barbuda announced this month that it had established the Redonda Ecosystem Reserve, covering nearly 30,000 hectares (74,000 acres) of land and sea, an area a quarter the size of Rome, which encompasses the terrain of the island as well as the seagrass meadows and coral reef surrounding it.

Arica Hill, the executive director of the Environmental Awareness Group (EAG), an NGO based in Antigua and Barbuda that was involved in the restoration effort, called the establishment of the reserve a “good jumping point” for future conservation action in the Caribbean, which is peppered with small islands overrun by invasive species.

“What we’re hoping to see is that we’ll be able to use the same model of NGOs working with government, working with private individuals and private agencies to come up with a system of managing an area,” Hill told Mongabay.

Removing invasive species has also been done to restore islands in many other parts of the world, including French Polynesia, Tonga and South Africa. The effectiveness of this restoration method is also supported by science. A 2022 study found that removing invasive species, such as rats, rabbits, cats and pigs, was 88% effective in restoring biodiversity on island habitats.

Daltry said she expects more positive changes on Redonda and its surrounding sea in the coming decades.

“Without vegetation, things were just crumbling into the sea, smashing up the reefs and the seagrass meadows,” Daltry said. “But we should see that pressure decrease on the coral reefs and the seagrass meadows to start to recover as well.

“When you remove rats on an island, seabird populations recover, and indeed, we can already see the seabird populations increasing,” Daltry added. “And there’s very close connections between the state of the seabirds and the state of fish.”

Hill said the most exciting part about Redonda’s restoration and establishment as a protected area is seeing “Antiguans and Barbudans fall in love with Redonda and be at the forefront of conservation action.”

“Antigua and Barbuda has not always been at the front and center [of conservation], and it’s not a picture that we’ve grown up seeing,” Hill said. “And I’m so excited and so proud of my team of people who are Antiguans and Barbudans.”

Banner image: Seabirds on Redonda Island cliffs. Image © Ed Marshall / Fauna & Flora.

Elizabeth Claire Alberts is a senior staff writer for Mongabay. Follow her on Twitter @ECAlberts.

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Citation:

Spatz, D. R., Holmes, N. D., Will, D. J., Hein, S., Carter, Z. T., Fewster, R. M., … Russell, J. C. (2022). The global contribution of invasive vertebrate eradication as a key island restoration tool. Scientific Reports, 12(1). doi:10.1038/s41598-022-14982-5