Document: EDW-3-16-1

Increased body size and reduced genetic diversity in invading populations of the European green crab.

GROSHOLZ, E.* ¹, G.RUIZ ², J.GELLER ³, M.BAGLEY ¹ and R.THRESHER ⁴

University of California, Davis, CA 95616 USA ¹
Smithsonian Environmental Research Center, Edgewater, MD 21037 USA ²
Moss Landing Marine Laboratory, Moss Landing, CA 21037 USA ³
CSIRO Marine Research, Hobart, Tasmania 7001 Australia ⁴

Abstract:
The European green crab (Carcinus maenas) represents one of the most significant coastal marine invasions in recent years. Over the last six years, we have documented a wide range of ecological and genetic characteristics in four independent invasions of this species: 1) eastern North America, 2) western North America, 3) southern Australia, and 4) Tasmania. One key result is that green crabs show a significant increase in body size in the introduced range relative to the native range. Using both recent field collections as well as literature-based estimates, we found mean body size is significantly greater in the introduced range relative to the native range. Body size in predatory crustaceans has important implications for ecological performance including prey availability, interactions with other guild members, and influencing reproductive output. In parallel with ecological studies, we have used molecular phylogeographic methods to understand both the pathways of invasion as well as changes in population genetic structure that accompany these invasions. Our analysis indicates that the western NA invasion originated from eastern NA and the Tasmanian invasion originated in south Australia. Furthermore, each invasion was accompanied by a dramatic loss of genetic diversity in comparison to the native European range. The link between increasing body size and decreased genetic variation in the introduced range relative to the native range is discussed.

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This abstract is being presented at: 2:35 PM in session:
Symposium #6: Ecological Consequences of Adaptive Evolution Among Invasive Species in Terrestrial and Marine Systems.