PARENT SESSION
Contributed Oral Session 108: Aquatic Trophic Systems II
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal
The role of predator diversity on sub-tidal food web composition and functioning.
Long, Zachary*,1, 2, Wall, Jessica1, O'Connor, Mary1, Bruno, John1, Duffy, J2, 1 University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA2 Virginia Institute of Marine Sciences, Gloucester Point, Virginia, USA
ABSTRACT- Ecologists have repeatedly demonstrated that predators can influence food web composition and dynamics, particularly in aquatic systems. What is less appreciated is the interactive effects of multiple predators and omnivores on food webs. We used aquatic mesocosms to experimentally investigate the strength of cascading effects of single predator species, multiple predator species, single omnivores, multiple omnivores, and combinations of predators and omnivores on the structure of a sub-tidal food webs in North Carolina estuaries. We established different food webs that consisted of macro-algal species, herbivores (amphipods and isopods), and different predator treatments (monocultures and combinations of fishes and crustaceans). We found that herbivore composition differed among predator treatments, and predators and omnivores significantly decreased total herbivore abundance. We also found that algal composition differed among predator treatments. Our results demonstrate that composition of the top trophic level can determine overall food web structure and ecosystem functioning in this system.
Key words: diversity, ecosystem functioning, food web, omnivory