Monster Seminar JAM - It's a Big Sea After All: Speciation and Population Isolation at Modest Spatial Scales
Dr. Michael Hellberg, Department of Biological Sciences, Louisiana State University
Marine populations are often thought to be well connected via long-distance dispersal of pelagic larval stages. The extent to which this holds true has been a matter of controversy whose resolution has strong implications for the management of marine resources and the design of marine reserves, as well as the understanding of diversification in the sea. Patterns of population connectivity can be inferred using genetic data. While the classic assumption of broad pelagic larval dispersal no doubts hold true for some taxa in some regions, a growing body of genetic and other data suggests that both speciation and population isolation can occur in marine animals at spatial scales too small (on the order of a 1000 km) to have been considered not long ago. Using examples drawn from gastropods, teleosts, and corals, I will show that 1) sister species commonly co-occur, 2) populations separated by no obvious physical barriers may remain genetically isolated for thousands of generations despite having pelagic larvae, and 3) even species with limited larval dispersal capabilities can shift their ranges rapidly in response to climatic change. Taken together, these genetic studies suggest that many marine populations experience dynamic allopatry: extended bouts of population isolation punctuated by rapid changes in connectivity and distribution.
Date and Time:
March 11, 2004,
11:00 am - 12:30 pm