Coexistence and competitive exclusion in mutualism

Area of Science:

• Ecology
• Evolutionary Biology
• Theoretical Biology

Background:

• The competitive exclusion principle explains species coexistence in consumer-resource systems.
• Mutualisms, where species interact for mutual benefit, also involve competition for shared resources.
• Existing theories do not fully address competitive exclusion within mutualistic interactions.

Purpose of the Study:

• To extend the competitive exclusion principle to mutualistic interactions.
• To develop a theoretical framework for understanding coexistence in mutualisms.
• To analyze the impact of competition on mutualistic partners.

Main Methods:

• Applying the competitive exclusion principle to mutualism.
• Deriving a novel rule analogous to Tilman's R* rule for exploitative competition.
• Investigating the effects of competition for partner-provided commodities and external resources.

Main Results:

• Coexistence is impossible if competitors rely solely on a shared mutualist-provided commodity.
• Resource partitioning of mutualist-provided commodities and external resources allows for coexistence.
• Competitive outcomes are influenced by resource acquisition abilities and the strength of mutualisms.
• Competition outcomes have significant consequences for the mutualistic partner, varying with mutualism type and competitor abilities.

Conclusions:

• Competitive exclusion theory can be effectively applied to mutualistic systems.
• Novel factors, including mutualism strength, influence coexistence beyond resource levels.
• The developed framework offers new insights into the dynamics of mutualistic communities and their stability.