In a new study published in Conservation Biology, researchers have found that removing invasive rats and restoring native vegetation on remote island archipelagos could lead to the return of hundreds of thousands of breeding pairs of seabirds. This study, led by researchers at Lancaster University, also calculated that there are enough fish in the surrounding seas to support these restored seabird populations. This inclusion of prey fish quantities in island restoration projects is a crucial consideration that has not been addressed in previous studies.
Dr. Ruth Dunn, lead author of the study, highlighted the devastating impacts of invasive species on native seabird populations, as they often consume eggs, chicks, and adult birds. Restoration projects that remove these invasive species, such as rats, have been proven effective, but it is essential to ensure that there will be enough fish in the sea for restored seabird populations to feed on. The researchers’ calculations showed that there is a sufficient supply of fish in the sea for the restored seabird populations on the remote Chagos Archipelago in the Indian Ocean.
The research team examined three scenarios where invasive rats were eradicated from 25 islands, and natural habitats were restored to varying degrees. Their modeling indicated that removing rats from these islands could result in a significant increase in breeding pairs of seabirds, including lesser noddies, sooty terns, and red-footed boobies. By restoring native vegetation to these islands, the number of breeding pairs could increase by up to 18-fold, potentially reaching over 280,000 pairs on some islands.
In addition to the benefits for seabird populations, the researchers found that seabirds play a critical role in cycling nutrients from the deep ocean onto islands and adjacent coral reefs. Seabird droppings contain nitrogen and phosphorus, essential nutrients that fertilize surrounding coral reef environments. By increasing seabird populations through restoration efforts, the researchers predict a significant increase in fish biomass on the reefs, which can help enhance the resilience of coral reefs to climate change impacts.
The study emphasizes the importance of considering the broader ecological context when planning resources for island restoration projects. By factoring in the impacts of restoring native vegetation and the availability of food in surrounding seas, restoration projects can maximize benefits for both seabird populations and coral reef ecosystems. The findings from this study provide valuable insight for guiding future island restoration projects worldwide, including the potential implementation of marine protected areas to limit fishing activity as part of these restoration efforts.
Overall, the research highlights the interconnectedness of island ecosystems and the potential benefits of restoring seabird populations for enhancing overall ecosystem health. By effectively managing invasive species, restoring native vegetation, and ensuring an adequate food supply for seabirds, island restoration projects can contribute to the recovery of vulnerable species and promote ecosystem resilience in the face of ongoing environmental challenges.