QCBS Students

Julien Massé Jodoin

McGill University
M.Sc. candidate

Supervisor: Frederic Guichard
Start: 2014-09-01

Assessing the impact of local biotic-abiotic interactions on the stability of a simple coastal ecosystem
Ecosystems state can display important fluctuations and undergo non-equilibrium dynamics potentially involving catastrophic shifts. Some ecosystems can also self-organize: their dynamical regime is not driven by environmental fluctuations but emerges from local interactions. Such dynamics can control disturbance and recovery of rocky shore mussel beds through aggregation behaviour and byssal attachment. Considering that mussels can increase bottom roughness and promote sedimentation, it is hypothesized that accretion could affect local mechanical stability of the mussel bed and result in large-scale disturbance and (in)organic matter resuspension events. A simplified mean-field ecosystem model is used to implement the interaction of mussel biotic processes with (in)organic matter fluxes and stocks at the local scale. Through computational analysis, the effects of this interaction on the persistence and dynamical stability of the system are studied. Future steps include thorough characterization of the dynamical responses through signal analysis and the implementation of inducted regional matter fluxes to explore resulting meta-ecosystem dynamics. Coastal ecosystem management has so far neglected to consider spatial flows of organic and inorganic matter and the fluctuations in their intensities as important drivers of ecosystems stability at the regional scale. The theory developed through this project will provide local and regional predictions of ecosystem dynamics resulting from non-trophic biotic-abiotic interactions with implications for sustainable management of changing ecosystems.