Microbial diversity in an intensively managed landscape is structured by landscape connectivity

Area of Science:

• Environmental microbiology
• Ecosystem ecology
• Biogeochemistry

Background:

• Intensively managed lands enhance nutrient and particle transport in basins.
• The effects on microbial community assembly at a basin scale remain unclear.

Purpose of the Study:

• To investigate how landscape connectivity and dispersal influence microbial diversity in an agricultural watershed.
• To analyze microbial community structure and interactions within the critical zone (water, soil, sediment).

Main Methods:

• Characterization of soil, sediment, and water microbial communities in the Upper Sangamon River basin.
• Statistical and network analyses to understand community structure and interactions.
• Bayesian source tracking to predict microbial community connectivity.

Main Results:

• Strong microbial connectivity was observed within environments (water, soil, sediment), but negligible connectivity between them.
• Species sorting, driven by media type and environmental parameters, was the dominant factor in community dissimilarity.
• Shared co-occurrence patterns in operational taxonomic unit networks suggest ecologically significant relationships across habitats.

Conclusions:

• Microbial dispersal is successful within, but not between, different environmental media in agricultural watersheds.
• Environmental parameters and habitat type strongly influence microbial community assembly.
• Identified shared microbial associations indicate key ecological interactions within the critical zone.