Meeting Abstract

11.7  Sunday, Jan. 4  Demographic history of the northeastern Pacific rocky shore community MARKO, P.B.*; MCGOVERN, T.M.; EMME, S.A.; COX, L.N.; HOFFMAN, J.M.; Clemson University; Clemson University; Clemson University; Clemson University; Clemson University pmarko@clemson.edu

Rocky shores have provided many insights into the responses of organisms to their biotic and abiotic environments, engendering some of the most important conceptual advances in the field of community ecology. Our understanding of the benthic and pelagic processes shaping patterns of contemporary community structure on rocky shores is fairly deep, but considerably less is known about the long-term persistence and stability of these model ecological communities over time scales longer than ~30 years. From a macroecological perspective, the relatively sharp zoogeographic boundaries between near-shore marine biogeographic regions indicate that rocky shore communities respond to spatial environmental factors as discrete co-evolved units. However, the fossil record has shown that some of these same species respond to temporal environmental change in a more individualistic manner. To compare the recent demographic histories of co-distributed and interacting species on rocky shores in the Northeastern Pacific, we conducted a multi-species survey of mitochondrial DNA diversity across 2500 km of coastline. Our study focuses on the northern two-thirds of these species’ ranges, where the impacts of Pleistocene climate change on population dynamics are expected to be greatest. All species examined to date show a similar mixed population history of recent rapid growth combined with the persistent signal of ancient haplotypes from earlier eras. The persistence of high haplotype diversity across most species suggests the long-term endurance of the entire community at relatively high latitudes despite enormous demographic change.