Ocean acidification increases the vulnerability of native oysters to predation by invasive snails

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Sanford, Eric, Gaylord, Brian, Hettinger, Annaliese, Lenz, Elizabeth A., Meyer, Kirstin, Hill, Tessa M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2014
• Subjects: Ocean acidification
• Online Access: http://dx.doi.org/10.1098/rspb.2013.2681; https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2013.2681; https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2013.2681

There is growing concern that global environmental change might exacerbate the ecological impacts of invasive species by increasing their per capita effects on native species. However, the mechanisms underlying such shifts in interaction strength are poorly understood. Here, we test whether ocean acidification, driven by elevated seawater p CO 2 , increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated p CO 2 experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO 2 oysters were consumed. The invasive snails were tolerant of elevated CO 2 with no change in feeding behaviour. Oysters raised under acidified conditions did not have thinner shells, but were 29–40% smaller than control oysters, and these smaller individuals were consumed at disproportionately greater rates. Reduction in prey size is a common response to environmental stress that may drive increasing per capita effects of stress-tolerant invasive predators.