PARENT SESSION
Oral Session # 83: Ecological Theory II: Modeling; Competition.
Presiding: C Brassil
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Meeting Room 201.
Competition for light between plant species with different foliage profiles: Formulation.
Vance, Richard*,1, Nevai, Andrew2, 1 University of California at Los Angeles, Los Angeles, California, USA2 University of California at Los Angeles, Los Angeles, California, USA
ABSTRACT- Mathematical study of how differences in plant architecture might influence interspecies competition for light requires population growth equations that include the benefits and costs of plant architectural features and yet remain simple enough to analyze. We will describe the formulation of such a model, beginning with the single-species case. This formulation incorporates explicit descriptions of three essential plant features: the vertical distribution of leaves and the vertical gradient in light intensity it creates, the photosynthetic response of leaves to light intensity throughout this gradient, and the metabolic cost of growing and maintaining stems whose lengths determine the vertical leaf distribution. These descriptions give rise to a population growth model that consists solely of a scalar ordinary differential equation of the Kolmogorov form, dx/dt = xf(x). The measure x of population abundance is the leaf area index, i.e., the total leaf area deployed by the plant population above each unit area of ground surface. Relatively direct scrutiny of the specific growth rate function f reveals the qualitative manner in which each feature of plant structure and function influences population growth, persistence, and equilibrium abundance. Straightforward extension of this formulation to two competing species sets the stage for examining how architectural differences might facilitate plant species competitive coexistence.
Key words: light, Kolmogorov, competition, population