The pink sea fan is a soft coral living in shallow waters from the western Mediterranean to the northwest of Ireland and the southwest of England and Wales. A new study led by the University of Exeter has found that, as global temperatures rise, this species is likely to spread northwards, including around the British coast. Since these corals are currently categorized as vulnerable by the International Union for Conservation of Nature (IUCN), the experts’ findings could be used to identify priority areas to protect pink sea fan populations.
Pink sea fans, as many other octocoral species, are ecologically important because they add complexity to reef systems and support aquatic biodiversity, particularly when they form dense “forests.” Moreover, they can also be used as broader indicators of ecosystem health, since fragmented or degraded colonies may be a sign of degraded environments.
“We built models to predict the current and future (2081-2100) habitat of pink sea fans across an area covering the Bay of Biscay, the British Isles, and southern Norway,” said study lead author Tom Jenkins, a research scientist at the University of Exeter. “The model predictions revealed current areas of suitable habitat beyond the current northern range limits of the pink sea fan, in areas where colonies have not yet been observed.”
According to Dr. Jenkins, it is not clear why pink sea fans have not yet colonized these areas, although insufficient dispersal of their larvae and high competition between species for habitats and resources could play a significant role.
“Our future predictions, using a high-emissions global warming scenario called RCP 8.5, revealed an increase in suitable habitat for pink sea fans to the north of its current range – so the species could spread northwards by 2100,” he added. “We also found that existing habitat across south-west Britain, the Channel Islands and northwest France is predicted to remain suitable for this species over the next 60-80 years.”
These findings highlight the complex impact of global warming on marine ecosystems. “In a rapidly changing mosaic of habitats, some species – typically those favoring warmer conditions – may come out as short-term ‘winners’,” said study co-author Jamie Stevens, an evolutionary biologist at the University of Exeter. “How long these species can continue to expand and benefit in the face of accelerated warming remains to be seen.”
The study is published in the journal PeerJ.