Christopher D. McQuaid1, Kevin C.K. Ma2, Cristian J. Monaco3
1Rhodes University, South Africa - 2University of British Columbia,Canada - 3IFREMER, IRD, Institut de Louis-Malardé, Univ Polynésie française, UMR-241 SECOPOL, France
Invasive species shape communities and ecosystem function worldwide. It is almost tautological to explain their success through their competitive superiority, yet few attempts to predict their responses to global change consider environmentally driven alterations to species interactions. The European mussel Mytilus galloprovincialis is a widely successful invasive in many parts of the world. In South Africa, it is the dominant mussel on the west coast, shows partial habitat segregation with the indigenous mussel Perna perna on the south coast and is absent on the east coast, which Perna dominates. This reflects the outcome of complex interactions among both biological interactions and physiological constraint. We wished to understand how the distribution of Mytilus around the coast of southern Africa is likely to be shaped by climate change. We used surveys, field experiments and modelling to elucidate the abiotic and biological limitations to Mytilus spread. Environmental conditions constrain Mytilus at multiple scales from within- and among-shore gradients of stress, particularly wave action and sand stress, to biogeographic gradients in temperature and chlorophyll. Biological interactions with the indigenous Perna are also critical at both within-shore and biogeographic scales and in addition are shaped by the within-species genetic identity of Perna. A modelling approach that explores the two species’ fundamental niches indicates that the effects of projected temperature conditions on their interactions and distributions will be less severe than expected and that the current spatial patterns of Mytilus and Perna are likely to be maintained until the end of the century.
Biography
Intertidal biologist with a wide range of interests often involving field manipulative experiments.