University of North Carolina at Chapel Hill Graduate School
Doi
Abstract
Parasites are more diverse and numerous than the organisms they feed upon, yet we know little about how parasites affect natural ecosystems. In salt marsh ecosystems of the southeastern U.S., increasing drought stress interacts synergistically with keystone grazing by marsh periwinkles to generate marsh die-offs. Field manipulation of digenean trematode parasite prevalence within the marsh food web under both drought and non-drought conditions revealed that parasites, by suppressing keystone grazing, can sustain multiple ecosystem functions and help prevent climate-induced die-off of foundational plants. A survey along 1000km of coastline showed that trematodes parasitism is common in marsh periwinkles and that increasing infection prevalence along marsh die-off borders is correlated with decreased per capita grazing and slower rates of Spartina marsh ecosystem decline. Combined, these results demonstrate that parasites can simultaneously regulate both the functioning of an ecosystem and its ability to resist die-off in the face of drought.Master of Scienc
