PARENT SESSION
Symposium 11: How Will the Southeast's Biological Diversity Respond to Climate Change?
Organized by: P White, J Walker, and J Sutter
Wednesday, August 6. 8:00 AM to 11:30 AM, SITCC Chatham Ballroom B.

Using genetics to differentiate among models of plant movement:lessons from the beach annual Cakile edentula.

Strand, Allan^*,1, Couillard, David¹, Niles, Kathryn¹, ¹ College of Charleston, Charleston, SC

ABSTRACT- A central component to understanding changing landscape-level demographic processes is dispersal. It is required to augment sizes of existing populations and for colonization of new or extirpated habitat. Fully understanding the role that dispersal plays at the landscape level requires an understanding of both the rate and pattern of movement. Unfortunately, characterizing dispersal ecologically is logistically difficult. Genetic markers provide an alternative approach to characterizing both the rate and pattern of dispersal. To demonstrate this genetic approach in a Southeastern plant species, we characterized chloroplast DNA-based genetic variation in 14 populations of the beach annual Cakile edentula var. Harperi. Chloroplasts typically are inherited maternally and provide a means to characterize seed dispersal. Based upon patterns of chloroplast DNA variation, Cakile populations in this region appear to be exchanging seeds at rates previously unreported in naturally dispersed plants. Furthermore, there is evidence that a stepping-stone model of dispersal best fits these data. Because it occupies essentially continuous habitat and disperses well, changes in climate are unlikely to affect colonization ability in this species. Estimates of near-future sea-level rise, however, suggest that suitable habitat will disappear and reduce overall numbers of populations.

Key words: water dispersal, molecular ecology