Dead coral, trees and oysters can still reshape ecosystems

A new study published in Science Advances finds that foundation species—including coral, oysters, mangroves, and large trees—can continue shaping ecosystems after they die, influencing whether recovery speeds up or stalls.

On a calm stretch of water near Moorea in the South Pacific, Kai Kopecky once swam over a reef that, by his account, looked almost too perfect—every square inch covered in living coral.

Then the next visit came after a different kind of event: a marine heat wave that triggered coral bleaching and left much of that life dead. Kopecky, a marine biologist, didn’t just notice the loss. He started asking what came next—whether the dead coral skeletons would help the reef bounce back. or whether they would slow recovery.

In the field, the contrast was stark. Coral bleached by heat waves dies in place, leaving behind a three-dimensional structure of skeletal remains. In tropical cyclones, by comparison, the coral can get scraped off the seafloor, leaving a flatter surface. Kopecky looked closely at how those different endings affected the reef’s ability to recover.

What he found was unsettling: the dead skeletons could hamper recovery. The reason was practical and physical. The skeletal remains offered nooks and crannies for seaweed and other species that compete with coral. In other words, the reef’s “foundation” didn’t simply disappear. The dead structure kept shaping what could settle and grow.

That observation fed into a broader question ecologists have wrestled with: foundation species are the architects of ecosystems. They range from the bottom of oceans to the tops of mountains and are often the most abundant organisms around—trees. grasses. oysters. kelp. They create microclimates, cycle nutrients, and provide habitat.

Kopecky wanted to know what happens when those organisms die. Do they leave behind legacies that help a system recover—or ones that drag it off track?

To tackle that, he recruited researchers across North America, pulling in expertise from different habitats. Among them was John Kominoski. an ecosystem ecologist at Florida International University. whose work focuses on mangroves and how they respond to disturbances like hurricanes. Storms, Kominoski explained, can defoliate mangroves and dump organic matter from the canopy onto the forest floor. The nutrients then become available for the remaining live mangroves to recycle and use. allowing roots to expand and the forest to recover.

So while coral bleaching left Kopecky with evidence that dead structure could interfere with coral regrowth, mangrove storms pointed toward a different possibility: the aftermath of death—or damage—could still supply the raw material for regrowth.

The study published in the journal Science Advances looked across 10 ecosystems. In nine of them, the dead had a strong influence on what the living could do afterward. To Kopecky, the takeaway is clear. Death, he says, isn’t necessarily an end. An organism can stop living, yet continue shaping an ecosystem’s trajectory.

The findings also offer a more complicated message than the simple idea of loss. Foundation species can leave legacies that are sometimes positive and sometimes not—meaning recovery doesn’t just depend on what disappears, but on what remains behind.

foundation species coral bleaching marine heat wave tropical cyclone mangroves hurricanes ecosystem recovery Science Advances ecology