Grant: Discovery Grants Program - Individual

Although marine sedimentary bottoms encompass a vast majority of the marine realm, our understanding of the processes that shape their biodiversity remains fragmentary. Most theory predicts that in unstructured marine sediments predation plays a paramount role regulating community structure. Indeed, numerous seminal studies have demonstrated that at the local scale, predators have the ability to regulate the dynamics of prey populations and communities. The role of predation, however, is not only the result of predator consumption of prey. Non-consumptive effects, where a predator modifies a trait of a mid-level consumer may also affect prey populations and communities without modifying the consumer's density. Mounting evidence from rocky shores and other well-known habitats suggests that these indirect effects, generically known as ""trait mediated indirect interactions"" may be at least as important as consumptive effects. Unfortunately, in habitats such as sedimentary bottoms, trait mediated interactions have not been given the same attention than consumptive effects. The alteration of a mid-level consumer's trait, for instance its behavioral patterns or feeding rates, may have consequences that cascade down to lower trophic levels and, therefore, should be carefully examined. I propose to assess trait mediated indirect interaction in sedimentary bottoms by taking advantage of a series of species and habitats present in the Atlantic region. This program aims to test a series of hypotheses that relate to three parallel research scenarios: the assessment of trait versus density mediated interactions in marine sediments, the role of trait mediated interactions in the co-existence of multiple predators, and the study of trait mediated interactions in predatory invaders. Considerable exploratory work already conducted in sediments associated to scattered biogenic habitats (oyster, mussel and eelgrass beds) embedded with marine sediments provides the basis for the research questions raised in this proposal. Considering their scope, the results of this program are expected to contribute to the theory behind species interactions in coastal sediments and other marine habitats.