Meeting Abstract
124.6 Tuesday, Jan. 7 14:45 Seaweed invader spans multiple biogeographic provinces in the western North Atlantic Ocean NEWTON, C*; BRACKEN, MES; THORNBER, CS; MCCONVILLE, M; RODRIGUE, K; Northeastern University; Northeastern University; University of Rhode Island; University of Rhode Island; University of Rhode Island newton.c@husky.neu.edu
The invasion of the western North Atlantic Ocean by the red alga, Heterosiphonia japonica has provided a unique opportunity to study invasion dynamics across a biogeographical barrier. Native to the western North Pacific Ocean, the initial invaded range of this invader in the western Atlantic was restricted to Rhode Island, USA in 2007 and 2009. However, through subsequent subtidal community surveys, we document the presence of Heterosiphonia in coastal waters from Maine to New York, USA, a distance of more than 700 km. This geographical distribution spans a well-known biogeographical barrier at Cape Cod, Massachusetts. Despite significant differences in subtidal community structure between the two biogeographic provinces, Heterosiphonia was found at all but two sites surveyed north and south of Cape Cod, suggesting that this invader is capable of rapid expansion over broad geographical ranges. Across all sites surveyed, Heterosiphonia comprised 14% of the subtidal benthic community. However, average abundances of nearly 80% were found at some locations. Our surveys suggest that the high abundance of Heterosiphonia has already led to marked changes in subtidal community structure as we found significantly lower species richness in recipient communities with higher Heterosiphonia abundances. Heterosiphonia has also been impacting local beaches and was found as intertidal wrack in abundances of up to 65% of the biomass washed up along beaches surveyed. Based on temperature and salinity tolerances from European populations, we believe Heterosiphonia has the potential to invade and alter subtidal communities from Newfoundland to Florida in the western North Atlantic Ocean.
