Seaweed replacement by coral under climate change

A study explores the factors that drive ocean community shifts in response to climate change. Climate change-induced range shifts in marine foundation species, such as corals and macroalgae, could have ecosystem-wide impacts on biodiversity, ecological functioning, and ocean resources. Recent studies have documented community shifts from macroalgae to corals in warm temperate zones, suggesting a possible avenue for coral conservation under climate warming. Naoki H. Kumagai and colleagues reconstructed long-term range shifts of kelp and fucoid seaweeds, corals, and herbivorous fish along the Japanese coast based on 60 years' worth of records. The authors modeled the range shifts as driven by a combination of temperature gradients and ocean current strength in response to climate change. According to the model, the rate and direction of shifts in the centers of species' geographic distributions and of species' expansions into new habitats were largely current-driven. Both temperature gradients and currents influenced the rate and direction of species' retreat from existing habitats. Herbivorous fish and corals expanded rapidly and kelps expanded slowly, whereas both seaweed types retreated rapidly. The authors estimated that the probability of climate-induced macroalgae-to-coral community shifts would increase in the near future, driven by both increased competition from corals and deforestation by herbivorous fish. According to the authors, the results highlight the complexity of future species range shifts under climate change.

Article #17-16826: "Ocean currents and herbivory drive macroalgae-tocoral community shift under climate warming," by Naoki H. Kumagai et al.

MEDIA CONTACT: Naoki H. Kumagai, Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Tsukuba, JAPAN; tel: +81-29-850-2470; e-mail: nh.kuma@gmail.com

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