Ocean

10 years of effort pay off as seaweed forest is restored to health

A new study shows that a decade of restoration efforts has helped a damaged underwater seaweed forest regrow to a level of richness and vitality comparable to forests that have never been disturbed.

A new study shows that a decade of restoration efforts has helped a damaged underwater seaweed forest regrow to a level of richness and vitality comparable to forests that have never been disturbed. Image: Pexels/Alexey Demidov

Angharad Brewer Gillham
Writer, Frontiers science
Share:
Our Impact
What's the World Economic Forum doing to accelerate action on Ocean?
The Big Picture
Explore and monitor how Ocean is affecting economies, industries and global issues
A hand holding a looking glass by a lake
Crowdsource Innovation
Get involved with our crowdsourced digital platform to deliver impact at scale
Stay up to date:

Ocean

  • Underwater seaweed forests are important ecosystems that provide food and shelter for other marine species. However, they are under threat from climate change, pollution, and overfishing.
  • A 10-year restoration project in the Bay of Maó, Menorca, has helped a damaged seaweed forest regrow to richness and strength comparable to forests that have never been disturbed.
  • The restoration project involved the reintroduction of a canopy-forming macroalgae species, Gongolaria barbata.
  • The study's findings offer hope for the future of marine restoration and suggest that even degraded ecosystems can be restored to their former glory.

Scientists show that efforts to restore the building blocks of marine ecosystems are paying off, with macroalgae that provide food and shelter for other species bouncing back over 10 years of growth in an underwater seaweed forest in the Mediterranean Sea.

Human activity has degraded ecosystems and damaged biodiversity around the world, but ecosystem restoration offers hope for the future. Scientists studying the restoration of underwater seaweed forests which provide other species with food and shelter have found that 10 years of restoration efforts have helped a damaged forest regrow to richness and strength comparable to forests that have never been disturbed.

“Macroalgal forests are found along over one-third of the world’s coastlines and underpin entire ecosystems,” said Dr Emma Cebrian of the Centre d’Estudis Avançats de Blanes, corresponding author of the study in Frontiers in Marine Science. “In 2011, a restoration action took place in the Bay of Maó, Menorca, where a macroalga species was reintroduced in the area where it used to thrive. After 10 years, we found that the associated algal species returned to the habitat, and with them, the ecosystem functions they provide.”

Discover

What's the World Economic Forum doing about the ocean?

Under the sea

Cebrian and her team used a trait-based approach to investigate the functional recovery of the seaweed forests: the link between restoration efforts and the forest functioning as it did before it was damaged. The team looked at five localities of Gongolaria barbata, one of the ‘canopy-forming’ species vital to maintaining seaweed forests, to understand how restoration of these species can work to revive the ecosystem.

“Among all seaweeds, canopy-forming macroalgae provide structure to the ecosystem similar to trees in a terrestrial forest,” said Cristina Galobart, first author of the study, also based at the Centre d’Estudis Avançats de Blanes. “They influence the local environment by altering, for example, the light and water flow. These modifications in the environment create ecological niches that other species can profit from.”

A new study shows that underwater forests can recover from impacts of climate change, pollution, and overfishing.
A new study shows that underwater forests can recover from impacts of climate change, pollution, and overfishing. Image: Image/Xavi Calsina

The evaluation of restoration projects tends to happen on short timescales, especially in marine ecosystems, where these projects are less established. However, projects that restore slowly maturing species need longer timeframes for assessment, and while we understand how vegetation structure and species diversity are restored, questions about how an ecosystem returns to function linger.

To measure function, it’s necessary to study quantifiable traits in the target species that capture the health of the ecosystem. The team chose to look at a suite of 14 traits, such as the size of specimens and whether they were from a longer-living or slower-growing species. The presence of species that need more time to mature or grow larger can indicate a healthier ecosystem, better able to support them.

The team looked at one actively restored locality, where restoration efforts had been ongoing for 10 years, a nearby locality where restored macroalgae had spread beyond the bounds of the initial restoration area, a neighboring locality that had not been restored, and two reference localities that had not been disturbed. They collected samples from each of these locations for identification and analysis, then dried and weighed the samples to measure the abundance of each species present.

Have you read?

Growing strong

They found that the restored locality was made up of a wider variety of species than the untouched locality and the area where restoration efforts had spilled over, with a similar composition of species to the reference samples. The restored locality was even more functionally rich than one of the reference forests, although it was not made up of exactly the species that the scientists had expected. The species that make up restored ecosystems may be different to the originals while still filling the same niche in supporting local biodiversity. The restored locality had greater structural complexity and species with longer lifespans, a crucial sign of long-term recovery which increases the potential shelter the forest provides for other organisms. The additional diversity also offers potential benefits for the future: a more diverse seaweed forest may be better able to respond to environmental challenges.

“We demonstrated that a single restoration action, plus the removal of the cause of degradation, can lead to the recovery of not only a single species but also the associated ecosystem functions,” said Cebrian. “Adding information from other restoration initiatives will help to completely understand how functionality is recovered in different habitats, species, or environmental conditions.”

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

Sign up for free

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.

Share:
World Economic Forum logo
Global Agenda

The Agenda Weekly

A weekly update of the most important issues driving the global agenda

Subscribe today

You can unsubscribe at any time using the link in our emails. For more details, review our privacy policy.

How deep-sea technology could transform life above water

Mattie Rodrigue and Diva Amon

February 23, 2024

About Us

Events

Media

Partners & Members

  • Join Us

Language Editions

Privacy Policy & Terms of Service

© 2024 World Economic Forum