Islands around the world have been decimated by introduced invasive species, but restoring islands — with a special focus on saving seabirds — provides benefits across land and sea. This is the message of a new perspective published December 5 in the Proceedings of the National Academy of Sciences (PNAS). The piece, “Harnessing island-ocean connections to maximize marine benefits of island conservation,” recognizes the role of seabirds as a critical link between island and marine ecosystems. It also identifies island and nearshore marine environmental characteristics that support ecosystem health. The research provides a model for effective land-sea conservation and management decisions.
The PNAS perspective underscores that coordinated, large-scale conservation of both marine and terrestrial habitats may offer unrealized and amplified benefits for biodiversity, human wellbeing, climate resilience, and ocean health. This new era of conservation must focus on the interconnectedness of all ecosystems, including “connector species” such as seabirds, rather than pursuing individual pieces through siloed efforts.
“By applying this knowledge to islands worldwide, we can understand the marine benefits of island restoration projects and maximize returns for our conservation management investments for people, wildlife, and the planet,” said Stuart A. Sandin, Ph.D., lead author of the perspective and a marine ecologist at Scripps Institution of Oceanography at the University of California San Diego.
Islands support some of the most valuable ecosystems on Earth, with a disproportionate amount of rare plants, animals, communities, and cultures found nowhere else. Healthy land-sea ecosystems depend on a flow of nutrients from oceans to islands and from islands to oceans, a process facilitated by seabirds and other connector species. Previous research has shown that islands with high seabird populations, which feed in the open ocean and bring large quantities of nutrients to island ecosystems through their guano deposits, are associated with larger fish populations, faster-growing coral reefs, and increased rates of coral recovery from climate change impacts.
Conservation focused on seabirds — including species such as the Red-footed Booby, Hawaiian Petrel, Sooty Tern, and Brown Noddy — provides important opportunities to benefit the marine and terrestrial habitats they inhabit. Many seabird species, however, have been driven to local or global extinction or near-extinction due to invasive nonnative mammals, such as rats that eat eggs and hatchlings and cats that hunt young and adult birds on islands where they nest. The loss of these connector species results in degraded ecosystems both on land and in the sea. Removing invasive species from islands is one of the best tools for restoring native plants, animals, and ecosystems.
‘Restoring bird populations has profound benefits’
“What ecosystem riches were lost when the Great Auk went extinct? Or the Large St. Helena Petrel? This new research supports the basic tenet of conservation that American Bird Conservancy (ABC) has been working with for many decades: Restoring bird populations has profound benefits to the habitats they live in — terrestrial, coastal, and marine,” said Sea McKeon, Ph.D., Marine Program Director at ABC. “This means that protecting marine birds throughout their life cycle and across the entirety of their migratory pathways should always be a top priority in the restoration of marine economies, islands, and ecosystems.”
“Advancing our understanding of marine and terrestrial linkages is invaluable for organizations like The Nature Conservancy to plan and execute effective conservation on islands and builds upon a foundation of indigenous knowledge about the land and sea,” said Nick Holmes, Ph.D., Associate Director for Oceans, The Nature Conservancy of California. “This underscores the importance of work in places like Palmyra Atoll, where The Nature Conservancy and partners are restoring seabird habitat and recovering extirpated seabird species to maximize land-sea connectivity and strengthen resilience to climate change.”
“Islands and oceans are connected — something many people living along coasts have long understood, depended on, and managed holistically as a result,” said Penny Becker, a coauthor on the perspective and Vice President of Conservation for the nonprofit Island Conservation. “Linking efforts on land, including removing invasive species from islands, with marine restoration and protection offers a significant untapped opportunity to protect and restore both islands and coastal regions.”
The insights put forward in the PNAS perspective can help shape where the most impactful marine co-benefits of island restoration could occur. The authors highlight six essential environmental characteristics that can guide prioritization of island-ocean restorations: precipitation, elevation, vegetation cover, soil hydrology, oceanographic productivity, and wave energy.
The paper identifies islands with higher rainfall, lower wave energy, and other conditions consistent with high land-sea connectivity, such as Floreana Island in Ecuador’s Galapagos Archipelago, as having high potential to produce substantial marine co-benefits after invasive species removal and island restoration.
“This research is incredibly useful for prioritizing where to focus conservation work and precious resources to have the greatest impact,” said Wes Sechrest, Ph.D., coauthor and Chief Scientist and CEO for the nonprofit Re:wild. “By restoring and rewilding Floreana Island, we now know that we will also be restoring and protecting wildlife in the Marine Protected Area surrounding the island and beyond and providing climate resilience. This is critical to building a sustainable Floreana for local islanders and a healthier planet for all life on Earth.”
Floreana residents have witnessed the negative effects of invasive species firsthand for decades and are shaping their island’s future by playing a central role in its restoration.
Sonsorol Island, Palau, is another site with high land-sea connectivity potential. The reduction in seabirds due to invasive species has significantly slowed nutrient deposition, which in turn is limiting the productivity of surrounding reefs. Sonsorol Island’s remoteness means that the community depends heavily on the local resources available to them. Prior to the impacts of invasive species, residents were able to thrive on the natural resources provided by the land and sea.
“Sonsorol and Floreana Island are just two of the many islands that hold great potential for healing marine environments,” said Kate Brown, Executive Director of the Global Island Partnership and coauthor on the paper. “Prioritizing island restoration across the globe can have a significant benefit for our world’s biodiversity, both on land and in the sea. Together, we can build resilient island communities supported by healthy island and marine ecosystems teeming with biodiversity.”
The Sonsorol and Floreana Island restoration projects are part of an ambitious new environmental campaign called the Island-Ocean Connection Challenge, which aims to restore and rewild at least 40 globally significant island ecosystems to benefit islands, oceans, and communities by 2030. Founding partners Island Conservation, Re:wild, and Scripps Institution of Oceanography launched the Island-Ocean Connection Challenge in April 2022 at the Our Ocean conference in Palau with the Republics of Panama and Palau. Supporters include the David & Lucile Packard Foundation, Oceankind, Cookson Adventures, the Leo Model Foundation, North Equity Foundation, and the Sheth Sangreal Foundation. Since then, the campaign has welcomed new partners and supporters, including the government of Chile, Danny Faure Foundation, the government of the Dominican Republic, the government of Ecuador, the Global Island Partnership, Marisla Foundation, and the Oceans Finance Company. American Bird Conservancy (ABC) has also joined and is committed to partnering on the holistic restoration of one island-ocean system in the Americas.