The effects of intransitive competition on coexistence

Area of Science:

• Ecology
• Theoretical Ecology
• Community Ecology

Background:

• Coexistence theory traditionally focuses on pairwise interactions, often overlooking complex indirect effects like intransitive loops in competition networks.
• Intransitive competition has been studied separately from other coexistence mechanisms, limiting understanding of their combined effects.
• Niche partitioning is a key driver of species coexistence, but its interaction with intransitivity remains unclear.

Purpose of the Study:

• To integrate intransitive competition into traditional coexistence theory.
• To develop a metric for quantifying the impact of intransitive competition alongside niche differences.
• To investigate how intransitive loops influence species coexistence dynamics.

Main Methods:

• Developed a metric of growth rate when rare (Δri¯) to assess intransitive competition.
• Utilized simulations of community dynamics to model species interactions.
• Analyzed the effects of loop length and topology on coexistence outcomes.

Main Results:

• Intransitive loops can either stabilize or destabilize species coexistence.
• The strength and significance of intransitive interactions are influenced by loop length and topology.
• The developed metric (Δri¯) effectively quantifies the impact of intransitivity.

Conclusions:

• Intransitive competition plays a significant role in species coexistence, interacting with niche partitioning.
• Ecological coexistence theory must incorporate complex, indirect interactions for a comprehensive understanding.
• The Δri¯ metric provides a tool for evaluating intransitivity in empirical ecological studies.