Evolution of dispersal under spatio-temporal heterogeneity

Area of Science:

• Evolutionary biology
• Theoretical ecology
• Population dynamics

Background:

• Environmental heterogeneity, both spatial and temporal, significantly influences the evolution of dispersal strategies.
• Previous models suggest spatial heterogeneity can hinder dispersal, while temporal heterogeneity promotes it via bet-hedging.
• Spatiotemporal heterogeneity in patch-structured populations can favor dispersal evolution, especially when individuals can use patch quality information.

Purpose of the Study:

• To generalize existing models of dispersal evolution under spatiotemporal heterogeneity.
• To investigate the evolutionary dynamics of conditional dispersal strategies when patch quality information is available.
• To explore the impact of arrival bias towards high-productivity patches on dispersal evolution.

Main Methods:

• Development of a generalized mathematical model for dispersal evolution in heterogeneous environments.
• Analysis of evolutionary game theory and reproductive-value arguments to understand conditional dispersal.
• Exploration of bistable evolutionary dynamics and parameter dependencies.

Main Results:

• Conditional dispersal strategies exhibit richer dynamics, including bistability, particularly with arrival bias towards high-productivity patches.
• A surprising result shows that offspring do not disperse from low-productivity patches where they were born.
• Dispersal from high-productivity patches can evolve, with parameter dependencies similar but not identical to unconditional dispersal.

Conclusions:

• The ability of individuals to use patch quality information for conditional dispersal significantly alters evolutionary outcomes.
• Conditional dispersal strategies, particularly avoiding emigration from low-quality patches, are crucial for understanding population dynamics in heterogeneous environments.
• Reproductive-value arguments provide intuition for the counter-intuitive finding of no dispersal from low-quality patches.