Proc Biol Sci. 2014 Jan 15;281(1778):20132681. doi: 10.1098/rspb.2013.2681. Print 2014.

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

Sanford E, Gaylord B, Hettinger A, Lenz EA, Meyer K, Hill TM.

Author information

• Department of Evolution and Ecology and Bodega Marine Laboratory, University of California Davis, , Bodega Bay, CA 94923, USA, Department of Biology, Northern Michigan University, , Marquette, MI 49855, USA, Department of Earth and Planetary Sciences and Bodega Marine Laboratory, University of California, , Davis, CA 95616, USA.

Abstract

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 pCO2, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO2 experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO2 oysters were consumed. The invasive snails were tolerant of elevated CO2 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.