Interactions of algal mats, plant communities, and storms in barrier island systems

Background/Question/Methods

The mechanisms by which of ecosystem engineers affect communities is an area of active interest in ecology. In coastal dunes, low-lying interdune habitats experience occasional severe flooding, which promotes the formation of algal mats. These algal mats have the potential to affect local community dynamics both directly by impeding seedling growth, as well as indirectly through moisture retention and nitrogen-rich biomass additions to otherwise very dry and nutrient poor sandy soils. This interaction between algae and vegetation depends on storm patterns, which are known to be effective drivers of coastal dune plant community composition. As part of my thesis, I intend to investigate the role of algal mats on coastal dune communities, and their potential for serving as ecosystem engineers.

Results/Conclusions

Preliminary analyses using long-term data from St George Island show a significant correlation between several specific plant species and the abundance of algal mat, suggesting that algal mats can have an effect on the resident plant community. This relationship will be investigated further using factorial greenhouse experiments including dominant coastal dune plant species and various storm condition simulations in greenhouse mesocosms. In this way, we will quantify the relationship between algal mats, soil nutrients, and dominant plant species in order to better understand the role of these mats in coastal plant community dynamics.