A new study published in Science Advances suggests that restoring native ecosystems on coral-fringed atolls could help these vulnerable landforms keep pace with rising seas. The research, which examined 28 atoll islands across the Pacific and Indian oceans, shows that healthy seabird colonies and native vegetation create a self-reinforcing cycle that builds and stabilises island sediment.
Tropical atolls, among the landforms most threatened by global warming, may have a natural superpower: thriving ecosystems that allow them to adapt to changing environmental conditions. An international team of scientists led by Nick Graham, a marine ecologist at Lancaster University in the United Kingdom, studied island resilience across 28 atoll islands in the Pacific and Indian Oceans.
The study, published this week in Science Advances, found that seabirds transport nutrients from the open ocean and deposit them on atolls as guano. This guano nourishes land plants and marine life, including coral growth, which in turn provides material for reef building. Parrotfish and other reef feeders convert dead coral into sand that maintains beaches, while native plants with extensive root networks stabilise sediments.
"Atoll islands with native vegetation and thriving seabird populations are naturally active systems that can change and adapt to their environmental conditions if they are allowed to do so," Graham said.
The findings suggest that rewilding atolls by restoring seabird colonies and native vegetation could reinforce natural growth processes, potentially helping islands keep pace with sea-level rise. Many atolls have been degraded by invasive species, habitat loss and human disturbance, which disrupts these ecological feedback loops.
Analysis
Why This Matters
- Atoll nations such as Tuvalu, Kiribati and the Maldives face existential threats from sea-level rise; natural adaptation mechanisms could complement engineered solutions.
- The study offers a relatively low-cost, ecosystem-based strategy that might be more sustainable and culturally appropriate than hard infrastructure.
- If rewilding proves effective at scale, it could reshape how vulnerable island communities plan for climate change.
Background
Tropical atolls are ring-shaped coral reefs that enclose a lagoon, with low-lying islands that rarely rise more than a few metres above sea level. They are formed over millennia by coral growth, sediment accumulation and biological processes. Rising sea levels and warming oceans threaten to outpace these natural building rates. Many atolls have suffered from overfishing, invasive rats that prey on seabirds, and clearing of native vegetation for coconut plantations or settlements. Restoration efforts have often focused on single species or habitats, but this study emphasises the interconnectedness of seabirds, coral reefs and vegetation.
Key Perspectives
[Researchers]: The study's authors argue that intact ecosystems give atolls an inherent capacity for self-renewal. By removing invasive species and protecting seabird colonies, managers can restore the nutrient flows and sediment production that maintain island elevation.
[Climate adaptation planners]: Ecosystem-based adaptation is gaining traction as a flexible, low-risk option, but its effectiveness depends on local conditions, the rate of sea-level rise, and the scale of restoration possible.
[Skeptics]: Critics may question whether natural accretion can keep pace with accelerating sea-level rise, especially under worst-case emission scenarios. They also note that rewilding alone cannot address other climate impacts such as ocean acidification or stronger storms.
What to Watch
- Pilot restoration projects on atolls that test the study's predictions, especially those that monitor island elevation changes over time.
- Policy decisions by atoll nations on whether to invest in ecosystem restoration alongside or instead of hard defences.
- Research into how quickly ecosystems can recover and at what scale rewilding becomes meaningful against projected sea-level rise rates.