![](https://sites.nicholas.duke.edu/silliman/files/2016/08/joe1.jpg)
I am deeply fascinated by parasites and the diverse roles that they play in coastal and marine ecosystems. The role of parasites in community ecology is often oversimplified, underappreciated or ignored. Parasites can play a powerful role in structuring communities, both directly by controlling organism abundance and indirectly through the facilitation of lower trophic levels via trophic cascades. While it is certainly true that parasites can have a negative impact on their host species, they can also be associated with processes or characteristics that are often regarded as “positive” attributes for ecosystems, such as enhancement of biodiversity and network stability. Currently, I’m investigating whether digenean trematode parasitism in salt marsh periwinkles (Littoraria irrorata) might help to mitigate overgrazing of Spartina habitat under sub-lethal salt stress conditions. Snail grazers and drought stress work synergistically to facilitate marsh die-off. Because infection with larval digeneans dramatically decreases the grazing rate of infected individuals, they may represent a source of ecosystem resilience.