Extending the gleaner-opportunist trade-off

Area of Science:

• Ecology
• Theoretical Ecology
• Evolutionary Ecology

Background:

• The gleaner-opportunist trade-off is a key concept explaining species coexistence, particularly its role in stabilizing competitor populations through differential responses to resource fluctuations.
• This trade-off, first proposed in the 1970s, describes how species adapted to low-resource environments (gleaners) differ from those thriving in high-resource environments (opportunists).

Approach:

• This review examines the historical development of the gleaner-opportunist trade-off theory and its associated mechanisms, such as the Armstrong-McGehee mechanism and relative nonlinearity of competition.
• It explores recent theoretical advancements suggesting that relative nonlinearity can facilitate coexistence across a wider range of ecological conditions than initially recognized.
• The study identifies and discusses novel extensions of the trade-off, including its applicability to fluctuating predation/pathogen pressure, multiple resources, and phenotypic plasticity.

Key Points:

• Contrary to some views, the relative nonlinearity mechanism can operate under more diverse conditions, promoting species coexistence.
• Extensions to the gleaner-opportunist trade-off demonstrate its relevance in complex scenarios involving environmental instability and species' adaptive capacities.
• A reframed understanding of the trade-off, focusing on performance in equilibrium versus fluctuating conditions, highlights its fundamental role in stable coexistence.

Conclusions:

• The gleaner-opportunist trade-off, when viewed through the lens of relative nonlinearity, offers a unifying framework for understanding species coexistence across various ecological contexts.
• This ecological trade-off is potentially more ubiquitous in nature than previously assumed, necessitating further theoretical and empirical investigation.
• Future research should explore the broad applicability of this trade-off in diverse ecological systems and under various environmental pressures.