A study by the University of Barcelona has analysed the ability of red gorgonians (Paramuricea clavata), a key species for the Mediterranean marine ecosystem, to resist and recover after marine heatwaves. The results, published in the Journal of Animal Ecology, show that the increased frequency and intensity of these extreme weather events - one of the consequences of climate change - will make these populations more vulnerable to future disturbances, beyond global warming and heatwaves, raising their risk of extinction. This negative impact would have a serious effect on marine ecosystems, according to experts.
"Paramuricea clavata is a species that plays an essential role in a type of community endemic to the Mediterranean Sea, the coralligenous. These communities have a high associated diversity and represent approximately 10% of Mediterranean species. Therefore, a decrease in the resilience of these species, or even their extinction, can lead to major changes in the structure and functioning of the Mediterranean seabed", warns Professor Pol Capdevila, from the Faculty of Biology and researcher at the UB's Biodiversity Research Institute (IRBio), first author of the article. IRBio researchers Yanis Zentner, Graciela Rovira, Alba Medrano and Cristina Linares, together with Joaquim Garrabou, from the CSIC Institute of Marine Sciences, have also participated in the study.
Study in the natural parks of Port-Cros and Montgrí, the Medes Islands and Baix Ter
In the study, the researchers conducted long-term monitoring, from 1999 to 2022, of nine populations of red gorgonians located in the Montgrí, Medes Islands and Baix Ter Natural Park, and in the Port-Cros Natural Park, with the aim of finding out the resilience of these organisms to marine heatwaves. "The Mediterranean Sea has warmed faster than the global oceans, making it one of the regions most affected by marine heatwaves, events that are expected to increase in frequency, intensity, duration and extent, even under the most optimistic climate change scenarios. Understanding the resilience of marine species to the increase in these extreme events is therefore crucial for predicting their viability under future climate conditions", note the authors of the paper.
The study shows that P. clavata populations exposed to heatwaves have lower resilience and slower recovery rates than populations that have not been exposed to these events. "These results suggest that increased heatwave frequency is likely to accelerate the extinction of shallower populations of P. clavata. And not only that: what we have observed is that, after suffering a heatwave, these populations are less able to resist and recover from other types of disturbances", Capdevila remarks.
This low resilience provides, according to the researchers, further evidence of the vulnerability of long-lived species to global change.
