PARENT SESSION
Contributed Oral Session 100: Modeling: Forest Systems
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 519 B, Level 5, Palais des congrès de Montréal

Ecological stoichiometry and the shape of resource-based tradeoffs.

Yoshida, Takehito^*,1, ¹ Cornell University, Ithaca, NY

ABSTRACT- Fitness tradeoffs are expected when organisms must allocate a limited resource between two or more traits. Despite the fact that most resources are made up of multiple elements or components, tradeoff models have traditionally been implicitly or explicitly based on a single currency. Here I propose a model for a resource-based tradeoff between two traits that share two resource elements, and suggest ecological stoichiometry as a critical mechanism controlling the shape of tradeoffs. The tradeoff curve in the model has different shapes depending on the elemental stoichiometry of the traits and the available resource. The tradeoff is predicted to be always non-linear or bent if resource stoichiometry is intermediate between the stoichiometries of two traits. The extent of bending also depends on how much distinct stoichiometries two traits have. This result suggests that even the same tradeoff would show quite different shapes depending on the environment where traits are measured. I further describe a conceptual framework that combines a tradeoff curve with a fitness function to predict an optimal combination of traits in stoichiometrically different environments. The model suggests that even though the fitness function is fixed, an optimal combination of traits can vary depending on the stoichiometry of both the traits and the supplied resource.

Key words: resource allocation, physiological tradeoff, multi-currency, optimal trait