9410966 Hairston In this proposal the PI's will address the role of dormant propagules in long-term population and community dynamics of two Daphnia species in Oneida Lake, New York. Although both species have persisted in the system for at least 30 years, their water-column densities are negatively correlated. One species is typically abundance while the other remains in low numbers. This transient dominance lasts for months or years, and has been attributed to a combination of competition and predation. This recurring pattern raises two questions: (1) how is each species able to persist over the long-term, and (2) if there is competition, why are both species present in the system? Both species produce diapausing eggs which remain viable in the lake sediments for a potentially long time period. By using theoretical models first proposed by Chesson and Warner (1981), the investigators will examine the hypothesis that the reproductive potential stored in these dormant eggs not only allows each species to persist in this system, but also enables long-term coexistence of two potentially competing species. To do this, the investigators will first consider the egg bank dynamics of each species independently. They will then test the hypothesis that the negative correlation between these two species is the result of competition.. Lastly, they will examine the role of the dormant eggs on the long-term interactions of the two species. %%% This dissertation research project will provide the first detailed investigation of an alternative mechanism for the coexistence of competing species in aquatic systems. Most studies focus on competition or predation, but the storage of propagules is a much neglected phenomenon which may be an important key to understanding factors that maintain biodiversity in aquatic and terrestrial systems.
