PARENT SESSION
Contributed Oral Session 9: Marine Ecology: Disturbance; Dispersal; Recruitment
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 519 A, Level 5, Palais des congrès de Montréal
Marine disturbance cycles: From landscapes to metapopulations.
Gouhier, Tarik*,1, Guichard, Frederic1, 1 Department of Biology, Montreal, Quebec, H3A 1B1
ABSTRACT- In marine systems, the occurrence and implications of disturbance cycles have been revealed at the landscape level, but because marine ecological theories posit that coastal habitats are open systems, landscape level dynamics is assumed to have no effect on regional dynamics. We present a mussel metapopulation model to elucidate the contribution of within-site disturbance cycles to the regional response of mussel populations to oceanographic productivity and larval transport. Within-site dynamics are generated through spatially-explicit rules and each site is connected to its neighbor through larval dispersal. The role of within-site disturbance cycles in the regional system behavior is elucidated (1) in open demographically-coupled systems, (2) along gradients of oceanographic productivity, and (3) in relation to the temporal scale of within-site dynamics. By controlling for spatial structure at the within-site and metapopulation levels, we first demonstrate the interaction between landscape and oceanographic connectivity. The temporal scale of disturbance cycles, as controlled by habitat quality, plays a critical role in the regional behavior of the system. Indeed, fast disturbance cycles are responsible for regional synchrony in relation to productivity gradients, and lead to regional stability in open metapopulations. Slow disturbance cycles, however, lead to increased robustness to changes in productivity and in demographic coupling. These testable predictions indicate that the occurrence and nature of disturbance cycles in landscapes can both drive large scale variability independently of demographic coupling, and determine the response of metapopulation dynamics to oceanographic changes.
Key words: marine disturbance cycles, open versus coupled system dynamics, demographic and spatial coupling, rocky intertidal zone