PARENT SESSION
Contributed Oral Session 76: Estuary and Coastal Management
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 514 A, Level 5, Palais des congrès de Montréal

Scale-dependent feedback and the spatial structure of coastal ecosystems.

Van de Koppel, Johan^*,, Altieri, Andrew, Silliman, Brian, Bertness, Mark,

ABSTRACT- Regular spatial patterns have been reported from a wide range of ecosystems. The most prominent examples are tiger bush found in arid systems, string patterns in boreal peatlands, ribbon forests, and banded mussel beds. A review of modeling studies indicates that a common mechanism may explain self-organized patterning in all these systems: the interaction between facilitation and competition dominating at different scales. Whether this mechanism influences the spatial structure of systems other then those with regular spatial patterning is so-far unknown. We present an experimental study on the importance of facilitation and competition in determining vegetation zonation in a cobble beach plant community. Our study revealed that the zonation of Spartina alterniflora and a zone of forb species occurring behind the Spartina was found to be caused, in part, by the interaction between long-ranged facilitation and short-ranged competition. Our study underlines that understanding how ecological feedbacks depend on spatial scale is crucial in understanding the large-scale structure and dynamics of ecological systems.

Key words: Zonation, Self-organization, Facilitation, Cobble beach