A study involving researchers from CEAB-CSIC has demonstrated the effectiveness of an innovative yet simple technique to mitigate the effects of major disturbances on gorgonian “forests”. The method, which involves pruning dead branches, has been scientifically validated over three years in the Medes Islands (Costa Brava, Catalonia, Spain).
Gorgonians are a species of soft coral essential for marine biodiversity. Like trees in terrestrial forests, they structure habitats and provide refuge and breeding grounds for a wide variety of species. However, these creators of “marine animal forests,” especially those found in shallow waters, are in decline due to human impacts, such as pollution, lost fishing gear, and especially marine heatwaves linked to climate change.
Researchers from the Centre for Advanced Studies of Blanes (CEAB-CSIC), the non-profit organization BIOSFERA, the University of Las Palmas de Gran Canaria (ULPGC), and the Institute of Marine Sciences (ICM-CSIC) have shown that strategically applying a simple technique helps gorgonian “forests” recover their health and regrow in a short time. The results of this research were published in the journal Biological Conservation.
The team of scientists has been studying gorgonian ecology for over twenty years. These “little trees” are formed by thousands of polyps that grow together in colonies. Like trees, some gorgonian branches may die, but the “tree” remains alive. After confirming that the death of some branches was harmful to gorgonians, they proposed scientifically studying the benefits of pruning them. This study was conducted between 2019 and 2022 in the Medes Islands, focusing on colonies partially affected by marine heatwaves and other impacts, which had lost live tissue covering parts of their internal skeletons.
The methodology –successfully tested on more than 1,000 colonies of Paramuricea clavata (the “red gorgonian,” an emblematic species of the Mediterranean)– involves “pruning dead branches”. Eduard Serrano, the lead researcher of the study, explains: “The gorgonians had lost around 20% of their live tissue due to extreme heat episodes and other impacts. These ‘dead branches’ are easily colonized by species like algae and bryozoans, which prevent them from recovering that part of the skeleton with new, live tissue. The colonization of these dead branches by other organisms adds weight and resistance to currents, which increases the likelihood of the gorgonian detaching from the substrate, thus threatening its survival.”
Gerard Mas, CEAB-CSIC researcher and co-author of the study, adds: “With this technique, by ‘pruning’ the gorgonians, we enable them to recover and grow again soon. We remove dead material, along with the risk of uprooting, while also eliminating colonizers that could suffocate them. This allows the gorgonians to focus on healing and feeding, which increases the survival chances of this soft coral and the ecosystem services it provides.”
Using this technique, the team has managed to double the survival rate of gorgonian “forests” in the area where the study was conducted. Moreover, in the colonies where this selective pruning was applied, growth rates were up to 2.5 times faster than in untreated control colonies.
Rafel Coma, another CEAB-CSIC researcher and co-author of the study, emphasizes: “It has been scientifically validated; it’s proven effective and does not require advanced technology or large investments. Strategically applying active restoration methods like this could help mitigate the effects of various anthropogenic pressures affecting gorgonian populations in the Mediterranean. However, it is essential to note that these interventions buy time by preserving the genetic diversity of populations, but they cannot counter the consequences of global change, including warming, habitat degradation, invasive species arrival, and other pressures related to human activity.”
The researchers involved in this study underline that restoration techniques can never replace the critical and urgent actions needed to reduce human pressures and their consequences. They urge coordinated action across all sectors to address the climate emergency with maximum effectiveness and speed.
Ref. Art.: Eduard Serrano, Gerard Mas, Oscar Serrano, Karina Inostroza, Marta Ribes, Rafel Coma, Pruning dead branches in gorgonian forests as an effective restoration tool against mortality events induced by global change, Biological Conservation, Volume 302, 2025, 110982, ISSN 0006-3207, https://doi.org/10.1016/j.biocon.2025.110982 (https://www.sciencedirect.com/science/article/pii/S0006320725000199)
* This research is part of the PODAGORG project by the BIOSFERA organization, funded by the Fundación Biodiversidad. It has also received financial support from the Museu de la Mediterrània and the Parc Natural del Montgrí, les Illes Medes i el Baix Ter
L'entrada A new technique to restore “forests” of soft corals ha aparegut primer a CEAB.