Why It Matters for Islands Everywhere

Islands are home to 31% of the world’s plant biodiversity. Rapa Nui illustrates how damaging invasive species can be to this precious resource, triggering cascading ecological collapse. And because island ecosystems evolved in isolation, islands are exceptionally vulnerable to invasive species, which can interrupt the flow of nutrients by eating seeds and seedlings. Similar rat-driven transformations have occurred across the Pacific, reinforcing the urgent need for rigorous biosecurity, rapid response, and restoration strategies. Safeguarding island biodiversity requires an integrated approach that tackles threats both on land and in surrounding marine environments. 

At Island Conservation, we have found that removing introduced, damaging invasive species from islands not only prevents biodiversity loss but also restores globally unique carbon stocks, making it a nature-based solution for climate resilience. For example, after invasive mammals were removed from Palmyra Atoll, native Pisonia forest cover increased by 5,000% in four years. Across 1,078 islands studied, eradication efforts collectively protect 940,000 hectares of forest and 53 million metric tons of forest carbon. Although islands are vulnerable to invasive species, they respond quickly when their ecosystems are holistically restored. This means that removing invasive species can help islands regenerate native forests, enhance carbon sequestration, and support climate policy goals. 

Terry L. Hunt, Carl P. Lipo

Reassessing the role of Polynesian rats (Rattus exulans) in Rapa Nui (Easter Island) deforestation: Faunal evidence and ecological modeling

Connecting Past and Present

Rapa Nui’s recent expansion of its Marine Protected Area reflects a growing commitment to ecosystem-based management. This research reminds us that conservation must be holistic: safeguarding marine life while preventing invasive species introductions on land. Without this integrated approach, conservation outcomes remain incomplete. 

Island Conservation’s work in Chile has included helping return native plants to Robinson Crusoe Island in the Juan Fernandez Archipelago. Together with the Islanders, we’ve helped plant more than 4,000 native plants, healing the terrestrial ecosystem. These benefits spread into marine ecosystems. Near islands where invasive species have been removed, such as in the Chagos Archipelago, coral growth rates could increase by 90%. 

This new study is one more link in the chain of emerging science that is helping us understand the true cost of invasive species for our planet’s islands and oceans—wisdom that has guided indigenous stewardship of islands for centuries. This knowledge is helping fuel holistic restoration around the world, and Rapa Nui’s Sea Council is leading the charge. By holistically restoring islands, we have the chance to make a lasting impact on climate resilience worldwide.