PARENT SESSION
Organized Oral Session 20: Disease in ecosystems: Reciprocal interactions between pathogens and ecosystems
Organizer(s): F Keesing, RS Ostfeld, and V Eviner
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 510b, Level 5, Palais des congrès de Montréal

Effects of disease on aquatic communities.

Lafferty, Kevin^*,1, ¹ USGS, University of California, Santa Barbara

ABSTRACT- Recent studies clearly indicate that infectious disease can affect aquatic communities and some information suggests that they are becoming more common. In the most basic sense, infectious disease can reduce the abundance of hosts. Indirect effects can also result through trophic cascades. For example, bacterial epidemics can reduce sea urchin population density, indirectly resulting in higher abundance of kelps. Parasites are important components of aquatic food webs (both as consumers and as prey) and can make up the bulk of trophic links. An increase in linkage density associated with parasites can increase the connectance of food webs, and this may have implications for community stability. Parasites may strengthen some links in food webs by pre-disposing their hosts to predation. In some cases, this appears to be an adaptation for increased transmission for the parasite. Killifish, for instance, are an order of magnitude more likely to be fed on by birds if they are infected with larval trematodes. Finally, parasites that affect habitat-forming species may indirectly act as ecosystem engineers. For example, infection by trematodes impairs cockle burial into mud and the exposed shells provide a unique hard substrate for sessile organisms.

Key words: trematodes, urchins, estuaries, marine