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Rats Gone, Tromelin Island Seabirds Thrive
24 Aug
Summary
- Rat eradication on Tromelin Island led to rapid seabird population recovery.
- Two seabird species doubled their numbers, with five more returning.
- Ecosystem recovery occurred despite the continued presence of mice.
Centuries of rat predation on Tromelin Island severely impacted its wildlife, reducing seabird diversity to just two species. A successful eradication of Norway rats in December 2005 marked a turning point for the small island in the western Indian Ocean.
The change was swift. By 2013, populations of red-footed and masked boobies more than doubled. This initial recovery paved the way for other species. White terns returned in 2014, followed by brown boobies breeding there for the first time.
Further recolonization occurred over subsequent years. By 2022, five additional seabird species had returned, expanding the breeding community to seven species. This natural return of species was aided by social attraction, where existing colonies encouraged new arrivals.
The island's vegetation also flourished, increasing from less than 30% to over 70% cover. This broader ecosystem recovery demonstrates the profound effect of removing a key invasive species, offering valuable lessons for island conservation efforts globally.
