Editor’s Note: Call to Earth is a CNN-edited series that, together with solutions, addresses the environmental challenges facing our planet. Rolex’s Permanent Planet Initiative is partnering with CNN to promote awareness and education on key sustainability issues and encourage positive action.
Vikal Atoll and Gemo Islands are classic island paradise from above. White sandy beaches, clear turquoise seas, lush forests. But for decades and centuries, even remotely deserted islands in the North Pacific, part of the Marshall Islands, have been overcome by rats.
When Paul Jack, a US-based nonprofit island conservation project manager, visited in 2024, both islands were raw with them. “They were running everywhere,” he told CNN. “If I walked around at night with a torch, it was almost horrifying. The forest floor was moving with mice.”
Rodents, invasive and likely to arrive as ship seats in the Marshall Islands, caused ecological disruption. They eat up native vegetation and feed on hatching of baby crabs, eggs and turtles. Islands, once refuge for people like colonies of endangered species of green sea turtles and seabirds, have seen their populations wrong.
“Because when the Spanish (explorers) first saw the gem, they called it “Rospajaros” (birds). “When I went there last year, there wasn’t that much.”
A year later, that’s another story thanks to an eradication programme carried out by the island’s conservation along with the Marshall Islands’ Maritime Resources Department and the Department of Natural Resources.
Rat food was dropped by drone in July 2024 – about 25 kilograms per hectare (55 pounds per 2.5 acres) – in line at the island, there was no coverage gap, Jack explains. Foods designed to target rats have little effect on other species. He adds that it needs to be widely used, as each rodent eats at least one pellet.
The team went on a long trip back to the island this summer to see if their work paid off.
“It’s like a big reveal,” Jack says. “The moment you step into the island, your senses are very recharged. You are looking for mice. You are looking for birds on the ground. You are looking for signs that will tell you whether you have won or if we have lost.”
Within an hour with Jemo and Bikar, he was sure it had worked and confirmed that rodents had been successfully eradicated from the two islands following intensive monitoring with trail cameras, rat traps, spotlight searches and heat detection devices.
Seabird populations were rising sharply. 2,000 sipping tern breeding colonies had established themselves in Bical, but before that there was nothing. Jack saw a great crested tern and brown nods nest on the ground, a Christmas shear extension – a dark brown seabird that he had never previously recorded in Bical – and a species of geckos and land clubs that were not present in 2024.
One of the most striking signs of success was the thousands of saplings of native Pishulia Grandis trees born across the forest floor. In 2024, they counted zeros. “To see the sapling carpet as soon as you return to the island was a really early sign for me that something radical had changed here,” Jack says.
Native flora and fauna rebounds help to restore the entire ecosystem. Seabird Guano (Feces) nutrients increase soil fertility. Crabs release larvae into the water and provide food sources for other marine animals.
Historically, Jemo Islet has been an important resource for the community living in Likiep, an atoll of about 40km (25 miles). They traveled to the islands, fished, looked for crabs, and weaved harvest crops such as coconut and pandan leaves. Although resources have dipped dramatically in recent years, they hope that the island’s communities (some of which are involved in conservation activities) will return to these traditions due to restoration projects.
“Jemo and Bikar once had giant rulies of seabirds and turtles. Now that rats have been removed, we look forward to recovering these colonies and the important natural processes connecting the deep seas, lands and reefs.”
“The successful removal of rats from Jemo and Bikar brings joy among traditional leaders and the people of Likiep, Utrik (close to Bikar), especially the Marshall Islands governmental Republic,” he added.
The current goal is to keep these islands rat-free, and because of their remoteness, Jack is sure this could happen. He explains that Bikar has been visited only recently by scientific exploration with careful biosecurity measures, and that due to community involvement and recognition of the disastrous effects of rats, residents of Likiep expect to be equally cautious when visiting Jemo.
There are no plans to reintroduce new species or modify habitats. “These islands are places that are left to regenerate themselves,” Jack says.
The successful eradication project hopes to serve as a blueprint for both the Marshall Islands and beyond. A feasibility study for Bokak Atoll is underway in Bokak Atoll, a semi-arid ecosystem similar to Bical. It is also found in major Marine Corps protected areas, and has been invaded by rats.
According to a 2023 report from the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), 90% of all global extinctions on the island are primarily due to invasive foreign species. However, we noted that eradication programs are cost-effective and have a high success rate of 88%.
If you can remove problematic invasive species, it is a gift that will continue to give. “Give 10 years, give 30 years, the changes are cumulative. The population increases and the animals reappear as if you thought you were locally extinct.
“This is why I continue to do this job, to see such a transformation.”
