Rat Eradication Helping to Preserve Historic Tongan Island

LATE ISLAND, Tonga — In a groundbreaking conservation initiative, Late Island in the Kingdom of Tonga stands as potentially the largest island in the Pacific to have been cleared of invasive rats, setting a remarkable benchmark for similar endeavors across the globe.  

The Director of Tonga’s Environment Department, a key partner in the project, Ms Atelaite Lupe Matoto, welcomes the initiative. 

“Removing invasive species like rats is one of the most cost-effective tools the country has for restoring the resilience of its natural ecosystems and its communities,” she said. 

“The primary problem for Tonga is that invasive species like rats and weeds are weakening the resilience of natural ecosystems and increasing the vulnerability of our communities to the increasing impacts of climate change. Controlling invasive species, like rats and weeds can protect our biodiversity and strengthen the resilience of our forests, catchment areas, and reefs, providing protection from cyclones, increasing food security, and creating opportunities from activities such as eco-tourism.” 

Late Island is a sanctuary of biodiversity for Tonga. It supports one of Tonga’s largest intact tropical broadleaf forest ecosystems, one of the most threatened ecosystem types in the world. This tropical forest provides a stronghold for several globally threatened species including the Friendly Ground-dove and Tongan Whistler. 

But as on many islands, invasive rats wreaked havoc on native species, devouring eggs, and threatening the essential nutrient cycle that supports the islands fringing reefs.  

Tonga has now completed a number of successful rat eradications on islands in the Vava’u group including Taula, Maninita, Lua Loli, Fangasito and Luahaipo.  Vava’u’s communities have already witnessed the significant impacts of this work, with the return of seabird populations and the increased productivity of local coral reef systems. Scientific studies have shown that, with the removal of rats and recovery of seabird populations, the increased nutrients from their guano can increase fish numbers by up to 50%. 

With completion of the Late Island eradication, together with Muomua and Fuaamotu island, Tonga is now leading the region on efforts to scale up the management of invasive species to increase the resilience of its ecosystems and communities to the increasing impacts of climate change. 

“Tonga is one of the first island nations in the world to attempt to manage invasive species and restore the resilience of its natural island ecosystems at a large landscape/seascape scale, thereby increasing community resilience to the impacts of climate change,” says Ms. Matoto.“Our development partners and donors need to understand that increasing investment in invasive species management is one of the most cost-effective things that we can do to restore the resilience of island ecosystems and communities." 

Tonga’s efforts to scale up investment in the management of invasive species is being supported by the Pacific Regional Invasive Species Management Support Service (PRISMSS) and key partners such as the global NGO, Island Conservation and the New Zealand Department of Conservation. PRISMSS is coordinated by the Secretariat of the Pacific Regional Environment Programme (SPREP), with support from the Global Environment Facility and the New Zealand Government.  

Future plans to remove invasive species from the islands of Tofua, Kao and Ata could provide refugia for an incredible 95% of Tonga's biodiversity and support future recovery efforts for endangered species. For example, removing invasive rats from Late Island now provides for the translocation of the highly endangered Tongan Megapode. Support for large-scale eradication projects on other islands such as Ata would also help justify their inclusion within Tonga’s National Park system. 

"The restoration and rewilding of Late Island does not stop here. We see the removal of invasive species as the starting line, not the endpoint," shares Mr Richard Griffiths, South and West Program Director for Island Conservation. “Once confirmed, we can look to reintroduce some of Tonga’s rarest species, such as the Tongan Megapode.” 

Ms. Matoto says PRISMSS and SPREP are directly supporting efforts by Pacific Island countries such as Tonga to increase investment in the management of invasive species as a key measure for increasing national resilience against the increasing impacts of climate change. 

“Tonga’s work to scale up investment in the management of invasive species is also providing a pathway for expanding predator eradication efforts into other inhabited islands across the Pacific, including Niue, the entire territory of Tokelau and communities such as Samoa’s Apolima Island.  

“This recent eradication work in Late Island could provide an important example for the Pacific and the rest of the world about the need to use invasive species management as a key tool for increasing climate resilience in many other Pacific Island countries,” she says. 

Bell Laboratories has been a longtime supporter of rodent eradication initiatives in sensitive environments, as well as a supplier of rodenticide for Island Conservation projects.