PARENT SESSION
Organized Oral Session 35: Mutualism, competition, and invasion: Applying ecological theory to agriculture
Organizer(s): LE Drinkwater, J Maul, DK Letourneau, and KL Monsen
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 511a, Level 5, Palais des congrès de Montréal

Assessing the relative role of competition and dispersal in determining the dynamics of plant populations in agroecosystems.

Maxwell, Bruce ^*,1, ¹ Montana State University, Bozeman, MT, USA

ABSTRACT- Competition between crop and weed species was historically thought to be the primary determinant of community assemblage in agroecosystems. Cellular automata simulation models including well established intra- and inter-specific interactions and seed dispersal theoretical models were used to determine the relative importance of these processes in determining species assemblage, population distribution and crop yield. Empirical data were used to characterize the variation in parameter values and determine if variation may preclude drawing any conclusion about the relative importance of processes. Simulation results under deterministic assumptions indicated that dispersal was more important than competition as a process influencing crop yield when weed populations were spatially aggregated. However, when weed populations were more highly mixed (high alpha diversity) the distinction between process importance is less identifiable particularly when parameter value variation is introduced.

Key words: population, dynamics, agroecosystem, community