Coexistence and community structure in a consumer resource model with implicit stoichiometry

Area of Science:

• Ecology
• Theoretical Ecology
• Consumer-Resource Models

Background:

• Optimal foraging theory and stoichiometry theory are key ecological frameworks.
• The MacArthur consumer-resource model is a foundational tool in community ecology.
• Understanding heterotroph community structure requires integrating resource acquisition and elemental needs.

Purpose of the Study:

• To integrate stoichiometry theory and optimal foraging theory within the MacArthur consumer-resource model.
• To predict diet choice, coexistence, and community structure in heterotroph communities.
• To explore how tradeoffs in consumer resource-garnering traits influence community outcomes.

Main Methods:

• Developed an integrated consumer-resource model combining stoichiometry and optimal foraging theories.
• Analyzed model predictions for diet choice under varying resource availability (scarce vs. abundant).
• Investigated conditions leading to coexistence and alternative stable states in heterotroph communities.

Main Results:

• Under scarce resources, consumers forage opportunistically, coexisting via encounter rate tradeoffs.
• Stoichiometry permits multiple equilibria, unlike single currency models, with alternative stable states linked to encounter rate vs. conversion efficiency tradeoffs.
• Under abundant resources, consumers exhibit selective diets, coexisting via elemental conversion efficiency tradeoffs.

Conclusions:

• Community ecology outcomes are significantly influenced by the interplay of stoichiometry and consumer foraging behavior.
• Tradeoffs in resource encounter rates and elemental conversion efficiencies critically shape community structure and stability.
• The integrated model provides a more nuanced understanding of heterotroph community dynamics than single-currency approaches.