Using null models to compare bacterial and microeukaryotic metacommunity assembly under shifting environmental...

Area of Science:

• Microbial ecology
• Environmental microbiology
• Community ecology

Background:

• Understanding temporal dynamics of microbial metacommunity structure and assembly is crucial.
• Environmental shifts, like heavy rainfall, can significantly impact microbial communities.

Purpose of the Study:

• To investigate temporal variations in microbial metacommunity structure and assembly processes.
• To assess how environmental changes influence bacterial and microeukaryote community assembly.

Main Methods:

• Conducted a 5-week temporal field study in rock pools with frequent sampling (4-day intervals).
• Characterized bacterial and microeukaryote communities using 16S and 18S rRNA gene sequencing.
• Applied null model approaches (elements of metacommunity structure, Raup-Crick beta-diversity, quantitative process estimates) to analyze community assembly dynamics.

Main Results:

• Strong environmental changes induced small but significant temporal shifts in assembly processes.
• Bacterial and microeukaryotic metacommunities exhibited distinct responses to environmental shifts, favoring different selection processes.
• Incidence-based analyses indicated stochastic processes govern community assembly, while abundance-based methods suggested historical contingency (bacteria) and unmeasured factors (microeukaryotes).

Conclusions:

• Microbial community assembly processes are not static and vary with environmental conditions and microbial groups.
• Environmental shifts can alter the relative importance of different assembly processes.
• Dispersal, selection, and contingency interact dynamically in shaping microbial metacommunities.