Meeting Abstract

71.6  Friday, Jan. 6  Intertidal population connectivity: limitations of climate and larval supply ROGNSTAD, R L*; WETHEY, D S; HILBISH, T J; Univ. of South Carolina, Columbia; Univ. of South Carolina, Columbia; Univ. of South Carolina, Columbia rhiannon@biol.sc.edu

In marine systems, connective processes are mainly constrained to the planktonic larval stages, as most benthic species are sedentary as adults. Though larval connectivity has been identified as a driving force in the establishment and maintenance of marine populations, the factors controlling the magnitude and extent of connectivity are not well-defined. Physical transport of larvae is a contributor, but other factors, including larval supply, must also be investigated. Populations of the barnacle Semibalanus balanoides in the United Kingdom provide an ideal system for testing the role of larval supply, as this species has a documented critical temperature for reproduction. The recent extreme European winters (2008-2009, 2009-2010, 2010-2011) provide us with a range of relevant temperatures and corresponding larval abundances. In 2010, we identified S. balanoides in Southwest England, an area where this species had been rare in recent decades. We predicted that recent cold winters have allowed increased recruitment in Southwest England. We tested this hypothesis by quantifying larval recruitment in Southwest England after the cold winters of ’08-’09 and ’09-’10. Prior to 2008, S. balanoides adults were uncommon in Southwest England, but abundant recruitment occurred in both cold years. Increase in recruitment between 2009 and 2010 allowed us to make predictions about further recruitment or range expansions of S. balanoides in Southwest England. Specifically, we predicted the cold winter of 2010-2011 would have allowed another season of abundant recruitment and range expansion into previously unoccupied areas of Southwest England, which we tested by quantifying recruitment during the summer of 2011.