New study overturns long-held assumptions about how plants spread to islands

When the volcanic island of Surtsey rose from the North Atlantic Ocean in 1963, it offered scientists a once-in-a-lifetime opportunity to observe how life takes hold on a brand-new and barren land. For decades, ecologists believed that plants’ ability to reach remote and isolated places depended mainly on special adaptations for long-distance dispersal — for example, fleshy fruits thought to attract birds, which would eat the fruit and later disperse the seeds — giving those species a decisive advantage in colonising new areas. 

A new study published in Ecology Letters challenges this long-standing view. Researchers from Iceland, Hungary, and Spain found that most of the 78 vascular plant species that have colonised Surtsey since 1965 lack any of the traits traditionally associated with long-distance dispersal. Instead, gulls, geese, and shorebirds have played the leading role in bringing seeds to the island — carrying them in their guts or droppings. In doing so, birds have transported a wide range of plant species, laying the foundations for Surtsey’s developing ecosystem. 

“Birds turned out to be the true pioneers of Surtsey — carrying seeds of plants that, according to conventional theories, shouldn’t be able to get there,” says Dr. Pawel Wasowicz of the Natural Science Institute of Iceland, one of the study’s authors. “These results overturn traditional assumptions about plant colonisation and show that to understand how life spreads and responds to environmental change, we must look at the interactions between plants and animals. Life does not move in isolation — it follows life.” 

Dr. Andy Green from the Estación Biológica de Doñana (CSIC, Spain), who co-led the research, adds: 

“Our findings have far-reaching implications for ecology and conservation. Animals — especially birds — are key drivers of plant dispersal and colonisation. As migration routes shift under a warming climate, birds will play a vital role in helping plants move and adapt to new environments.” 

The study underscores the exceptional importance of Surtsey as a natural laboratory, where scientists can observe the fundamental processes of life — how ecosystems emerge, evolve, and respond to environmental change. It calls for new ecological models that account for real biological interactions rather than relying solely on seed traits or taxonomic classifications. 

“Long-term research like that carried out on Surtsey is invaluable for biology,” says Dr. Wasowicz. “It allows us to witness ecological processes that would otherwise remain invisible — how life colonises, evolves, and adapts. Such work is essential for understanding the future of ecosystems in a rapidly changing world.”