THE EFFECTS OF ZOOPLANKTON DISPERSAL ON COMMUNITY ASSEMBLY OF TEMPORARY PONDS

Abstract

The dispersal of individuals among habitat patches is thought to have an important effect on ecological communities as it can influence both population dynamics and community assembly. Though much work on dispersal has been completed, zooplankton offer an interesting opportunity to study dispersal. They can disperse not only among ponds, but they can also disperse within and among ponds through time as their eggs can remain dormant for long periods until environmental conditions initiate their hatching. The dissertation has focused on the role of temporal and spatial dispersal on the assembly of zooplankton communities, an assessment of whether predators weaken the effect of early dispersing zooplankton species on late dispersing zooplankton species through differences in zooplankton hatching phenology, and the effects of environment and space on temporary pond zooplankton communities in the Croatan National Forest, NC. Differences in spatial and temporal dispersal had a weak effect on the number of zooplankton species present. Nonetheless, both spatial and temporal dispersal strongly affected the total abundance and species composition of zooplankton present, but their effects were interdependent. When predation and the effects of zooplankton hatching phenology were considered predators and one zooplankton species that arrived early slowed the growth of the later arriving zooplankton species. Algal resources were not affected by predators, but were affected by the order of arrival of the different zooplankton species. Lastly, the role of environment and space on zooplankton temporary pond communities showed that spatial and environmental factors explained similar amounts of the variation in zooplankton composition in the Croatan National Forest, with environmental factors explaining more of the variation in the spring and summer than in the fall and winter. Together these results indicate that zooplankton composition in pond communities can be affected by interactions between spatial and temporal dispersal, the presence of predators and differences in hatching phenology, as well as by environmental factors such as temperature and spatial factors such as pond size and pond density. Thus, highlighting the importance of dispersal but also its interaction with other abiotic and biotic factors to form zooplankton communities.