Founders Can Increase Determinism of Community Assembly

Area of Science:

• Ecology
• Microbial Ecology
• Community Ecology

Background:

• The influence of initial colonizing species, known as founders, on community assembly is critical but lacks direct experimental evidence at the community level.
• Priority effects and studies on artificially assembled species suggest founder effects play a key role in shaping community composition, functionality, and stability.

Purpose of the Study:

• To experimentally investigate the impact of founders on microbial community assembly.
• To explore how founder presence influences community diversity, stability, and the dominance of deterministic versus stochastic processes under varying dispersal conditions.

Main Methods:

• Utilized sterilized and non-sterilized paocai soup as initial environments with and without founders.
• Exposed these environments in beakers with varied opening sizes on a rooftop for 15 days to simulate different dispersal intensities.
• Employed 16S rRNA sequencing for microbial community analysis.

Main Results:

• Communities with founders exhibited significantly lower species richness (320 vs. 645) and reduced species turnover (53.7% vs. 60.9%) compared to those without founders.
• Founder presence led to higher community stability, indicated by a lower Average Variability Degree (AVD) (0.446 vs. 0.927).
• Deterministic processes, particularly heterogeneous selection (70%), dominated communities with founders, while stochastic processes were more prevalent in communities without founders.

Conclusions:

• Founder presence reduces the impact of dispersal, lowers community diversity, and enhances stability.
• The initial colonizing species fundamentally shape community assembly, directing ecological trajectories.
• This research provides crucial experimental evidence for founder effects in community assembly and biodiversity maintenance.