A team of researchers from CEAB-CSIC demonstrated the effectiveness of a simple and innovative technique to mitigate the effects of environmental disturbances on gorgonian forests. This strategy, based on pruning branches of dead soft corals, was scientifically validated over three years in the Medes Islands, in L’Estartit-Torroella de Montgrí (Girona).
Gorgonians are soft corals fundamental for marine biodiversity, as they structure the habitat and provide refuge and breeding areas for numerous species, playing a role similar to trees in terrestrial ecosystems. However, these “underwater forests” are declining, especially in shallow waters, due to various threats such as pollution, ghost fishing, and above all, marine heatwaves associated with climate change.
Researchers from the Advanced Studies Center of Blanes (CEAB-CSIC), the BIOSFERA entity, the University of Las Palmas, and the Institute of Marine Sciences (ICM-CSIC) discovered that pruning dead branches allows gorgonians to recover their health and regenerate faster. Their findings, published in the journal Biological Conservation, scientifically support this technique as an effective restoration method.
After more than 20 years studying the ecology of gorgonians, scientists observed that, although some branches die naturally, the accumulation of dead tissue negatively affects colony survival. To assess the impact of pruning, they conducted a study between 2019 and 2022 in the Medes Islands, applying the technique to over 1,000 colonies of Paramuricea clavata (red gorgonian, an emblematic species of the Mediterranean).
Benefits of pruning in the recovery of gorgonians
Eduard Serrano, lead researcher of the study, explains that the analyzed gorgonians had lost around 20% of their living tissue due to extreme heat episodes and other impacts. Dead branches are quickly colonized by organisms like algae and bryozoans, hindering the regeneration of living tissue and adding weight, while increasing resistance to currents and favoring the detachment of the gorgonian from the substrate.
Gerard Mas, co-author of the study, emphasizes that removing these dead branches reduces the risk of detachment and eliminates colonizing organisms that could suffocate the gorgonian. “By pruning them, we give them the opportunity to focus on their recovery and nutrition, increasing their survival and that of the ecosystems they support,” he states.
The study’s results were conclusive: in areas where pruning was applied, gorgonian survival rates doubled and growth was up to 2.5 times faster compared to unpruned colonies.
What are the benefits of soft corals for the environment?
Soft corals are a natural habitat for many fish and help protect coasts from natural disasters. The benefits of soft corals for the environment include:
- Coastal protection: they act as natural barriers protecting coasts from waves, storms, hurricanes, and tsunamis.
- Shelter for fish: they are a breeding and refuge site for fish and other marine animals.
- Water filtration: they help clean coastal waters.
- Medicine: medicinal components have been found in the marine species inhabiting coral reefs.
Coral reefs are vital ecosystems for ocean health and planetary biodiversity.
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