Multiple phase transitions shape biodiversity of a migrating population

Area of Science:

• Ecology
• Evolutionary Biology
• Microbial Ecology

Background:

• Closely related microbial strains often coexist, maintaining high biodiversity in natural systems.
• Mechanisms stabilizing microbial coexistence, particularly in environments like the gut microbiome, are not fully understood.
• Spatial heterogeneity is a known factor, but organism dispersal rates significantly modulate its impact on diversity.

Purpose of the Study:

• To investigate the impact of migration rate on biodiversity within a model of heterogeneous selection pressure.
• To understand the relationship between migration dynamics and the stability of microbial communities.

Main Methods:

• Development of a simple evolutionary model incorporating heterogeneous selection.
• Analysis of the biodiversity-migration rate relationship under varying dispersal conditions.
• Examination of phase transitions and critical slowing down (CSD) dynamics.

Main Results:

• The relationship between biodiversity and migration rate is characterized by multiple phase transitions.
• A reentrant phase transition leading to coexistence was identified.
• Ecotype extinction occurs at each transition point, accompanied by critical slowing down (CSD).

Conclusions:

• Migration rate is a critical determinant of microbial biodiversity and community stability.
• Critical slowing down, detectable through fluctuation statistics, can signal impending ecotype extinction.
• These findings may offer experimental approaches for monitoring and intervening in biodiversity dynamics.