Meeting Abstract

35.4  Thursday, Jan. 5  Extreme events and biogeography of range boundaries in the European intertidal WETHEY, DS*; WOODIN, SA; HILBISH, TJ; LIMA, FP; JONES, SJ; Univ South Carolina, Columbia; Univ South Carolina, Columbia; Univ South Carolina, Columbia; CIBIO, Univ Porto, Portugal; NOAA, Washington DC wethey@biol.sc.edu

Against the background of several decades of gradual warming, the severely cold winter of 2009-10 in Europe caused interruption or rapid reversal of long term shifts in geographic distributions of some intertidal species. After decades of poleward retreat, the northern barnacle Semibalanus balanoides expanded its range in both France and Iberia at rates in excess of 25 km y-1 and reinvaded locations where it had not been seen for 40 to 60 years. The southern mussel Mytilus galloprovincialis and the southern barnacles Chthamalus had been expanding their northern ranges in France in response to several decades of warming winters, but suffered reproductive failure in 2009-10. The southern polychaete Diopatra which is sensitive to cold summers, had little to no change in distribution, as a result of the prior warm summer. The magnitude and duration of these biogeographic responses to extreme events depends upon a combination of metapopulation dynamics and demographic storage effects.