Signs of stabilisation and stable coexistence

Area of Science:

• Ecology
• Population Biology
• Theoretical Ecology

Background:

• Empirical studies often quantify negative density dependence, negative frequency dependence, or negative plant-soil feedback.
• The direct links between these empirical findings and ecological theory for stable coexistence are often unclear.

Purpose of the Study:

• To connect empirical measures of density dependence, frequency dependence, and plant-soil feedback to theoretical conditions for stabilization and stable coexistence.
• To evaluate the sufficiency of common empirical tests for predicting stable coexistence in ecological communities.

Main Methods:

• Relating empirical results to classical competition models and theoretical conditions for stabilization.
• Analyzing whether common empirical tests provide necessary or sufficient conditions for stable coexistence in two- and multi-species systems.
• Discussing invasibility experiments and model parameterization as approaches for stronger coexistence tests.

Main Results:

• Most tests for negative density dependence, negative frequency dependence, and negative plant-soil feedback are sufficient for ecological stabilization in two-species interactions.
• These empirical tests are neither necessary nor sufficient for stable coexistence of two species.
• Inferences are more limited for multi-species communities and single-life-stage/vital rate measurements.

Conclusions:

• While empirical measures indicate stabilization, they do not reliably predict stable coexistence.
• Model parameterization offers a robust approach to link empirical data with coexistence mechanisms.
• Invasibility experiments and model parameterization provide stronger frameworks for testing stable coexistence.