Birds may decide where plants survive in the future

Imagine witnessing the birth of land. In November 1963, deep beneath the surface of the North Atlantic, a volcanic eruption began constructing an entirely new island from magma and ash. Within months, Surtsey emerged above the water.

No soil, trees, grass or footprints were present on the island. Just raw black rock, steaming, shifting, uninhabited. To scientists, this was a miracle. A fresh world and living question unfolding from nothing.

Who would arrive first? What rules does life follow when there is no history to inherit? Do plants wait for wind to carry them? Or does nature work through hidden alliances we take for granted?

For decades, ecologists believed the answer was simple. Only plants with special traits could colonize such empty space.

Lightweight seeds built for wind. Fleshy fruits designed to attract animals. Built-in travel machinery. Nature, they believed, rewarded design. But on Surtsey, reality played a different game.

A new beginning

From 1965 onward, botanists began returning every year. Each plant that emerged on Surtsey was logged with extreme precision. Nothing was left to chance. And something strange appeared in the records.

The majority of arriving plants were not built for long-distance travel. No fluffy sails for wind. No attractive fruit for animals. Most were dry seeded species assumed to possess near zero capacity for flight or gut survival. Their seed structures should have disqualified them.

Yet the plants still arrived. And they continued to arrive. Today, 78 vascular plant species have colonised Surtsey. Most of them lack any traditional dispersal adaptations. Yet they crossed 30 kilometers of ocean.

So how did they get there? The researchers found the answer not on the ground, but in the sky.

Birds bring life

Gulls, geese and shorebirds were visiting Surtsey almost immediately after it formed. They treated it as a resting point – a feeding stop and place to land before returning to Iceland or other islands.

And critically, the birds were not traveling empty. They were carrying seeds inside their bodies.

“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,” said Dr. Pawel Wasowicz of the Natural Science Institute of Iceland.

“These results overturn traditional assumptions about plant colonization 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.”

What ecologists long overlooked is that birds do not require fleshy fruit to transport plants. Many non-fruiting species with tiny dry seeds remain completely viable inside bird digestive systems.

Gut passage does not always destroy. In many cases, it transports. Sometimes it even enhances germination. This was not a one-off event. It was a system.

Change in birds and plants

Everything changed in 1986, when Surtsey’s first large gull colony permanently established itself.

From that year onwards, colonization accelerated rapidly – in both speed and spatial concentration. New plants no longer appeared randomly across the island. They appeared directly where birds nested.

And not just from droppings. Birds dragged plant material for nest construction. Their guano fertilised the barren volcanic soil, allowing weak colonizers to survive. They created nutrient hotspots in an otherwise sterile landscape.

“Our findings have far-reaching implications for ecology and conservation. Animals – especially birds – are key drivers of plant dispersal and colonization,” noted Dr. Andy Green from the Estación Biológica de Doñana (CSIC, Spain).

“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 shattered the core assumption that seed design alone decides survival. Birds were not simply helpers. They were infrastructure. They were the first engineers of the ecosystem.

Birds and plants reshape ecosystems

Across three major European dispersal classification systems, the majority of Surtsey species were labeled as possessing no dispersal adaptation. Yet direct field evidence confirmed avian gut transport for 62 of the 78 colonizing species.

Even worse for conventional models – the three classification systems disagreed with each other. Two plants might be labelled wind dispersed in one system, gravity dispersed in another, and unassisted in a third.

The disagreement rate reached nearly 90 percent. The categories were failing long before the island proved they were wrong.

The study makes a sharp point. Biology has assumed for too long that a fruit must be fleshy before a bird considers it. That mobility is rare. That dispersal is passive and that form predicts function. Surtsey says otherwise.

This island shows that evolution may favor invisibility over spectacle. It also shows that some of the most effective travelers are not the showy fruits, but the tiny dry seeds, silent and easily ingested during foraging.

The future of birds and plants

This work lands in a future where ecosystems are about to move – or vanish. As climate zones shift northward and upward, species migration is no longer a slow geological drift. Survival now depends on mobility.

That was once assumed to be a wind problem. It is now clear that it is a bird problem.

“Long-term research like that carried out on Surtsey is invaluable for biology,” said Dr. Wasowicz. “It allows us to witness ecological processes that would otherwise remain invisible – how life colonizes, evolves, and adapts.”

“Such work is essential for understanding the future of ecosystems in a rapidly changing world.”

The lesson is clear. Life is not a solo act. It moves in collaboration. Birds may become the emergency transport system for plant survival. And the next Surtsey may not be a volcanic island, but entire biomes forced to relocate.

Understanding where plants can go next means understanding where birds will go first.

The study is published in the journal Ecology Letters.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–