Nature reveals an intricate web of connections. Changes in a single place can ripple far beyond, even across oceans. An international research team reports that eliminating invasive species on land may trigger remarkable improvements in nearby marine systems. They advocate restoring islands affected by non native plants and animals as a strategy to boost the marine environment while increasing resilience to climate shifts.
Islands harbor unique plant, animal, and human communities not found elsewhere. Local and global stressors threaten these fragile ecosystems, and invasive species rank among the most damaging yet solvable pressures, the researchers state.
Though land mammals pose a well known threat to island flora and fauna, new findings indicate their impacts extend into adjacent waters, creating extensive and damaging effects on nearby marine environments.
Eradicating invasive mammals and restoring the natural biota emerge as promising tools to address both island and ocean management goals, according to scientists from the United States, New Zealand, and the United Kingdom.
Across thousands of studies, researchers confirm that removing invasive species and restoring island ecosystems also yields notable benefits for underwater environments.
Study of “connector types”
In what the authors describe as a key factor, the paper published in the Proceedings of the National Academy of Sciences details how land and sea ecosystems connect through seabirds, seals, turtles, and species that shuttle nutrients between the ocean and the islands. This includes sea snakes or crabs that move material back and forth, linking terrestrial and marine food webs, the scientists explain. They emphasize that protecting and restoring these habitats is essential.
Efforts to control land invasives, paired with marine restoration and protection, could amplify conservation gains and help meet broader, global goals for biodiversity—an approach supported by the researchers as a way to maximize outcomes.
Experts call for sustained investment in land and sea monitoring tools, informed by science, to drive integrated land-sea management.
Conservation specialists recognize that addressing climate change, ocean stressors, and the biodiversity crisis requires mindful investment in management actions that yield practical, lasting results.
The paper also highlights the value of including long standing human knowledge from island communities and embracing diverse perspectives within ecological and environmental sciences.
Researchers predict striking results if actions are executed with care: well chosen conservation measures on the islands could trigger surprising changes in the neighboring ocean, underscoring the idea that everything is connected, according to Penny Becker of Island Conservation, a co author of the study.
Examples include seabirds that feed at sea and deposit nutrients on land through excrement, carcasses, eggs, and other reproductive materials, as well as feathers and molts, creating nutrient pathways across habitats.
The more seabirds, the more fish
Seabird activity stirs soil through burrowing and other actions, mixing nutrients and sometimes aerating the soil. In turn, nutrients from land are released into the sea when land crabs spawn. Nutrients can also travel to the sea via rainfall and other water movements, helping to sustain productive near shore ecosystems.
In Palmyra Atoll and other sites, researchers observed a substantial rise in organic nitrogen in stream waters where seabird colonies nest, illustrating how seabird presence can influence adjacent waters. The study notes that larger seabird populations correspond with higher fish abundance in nearby seas and can also support faster growing, climate resistant coral reefs.
However, seabird populations are declining globally, with declines largely tied to human activities—especially the introduction of non native mammals such as mice, rats, pigs, and goats that raid burrows. Loss of these key species can trigger ecosystem collapse on both land and sea, the authors warn, urging immediate action across tools and strategies to reverse the trend.
Reference: a study in the Proceedings of the National Academy of Sciences, 2021, summarized without linking to external sources.
End note: environmental agencies stress the importance of coordinated action to protect island ecosystems and the surrounding marine environments.