Substrate and low intensity fires influence bacterial communities in longleaf pine savanna

Area of Science:

• Ecology
• Microbiology
• Fire Science

Background:

• Bacterial communities at vegetation-soil interfaces are vital for terrestrial ecosystems.
• Research on these communities is limited in fire-prone grasslands and savannas, unlike unburnt or high-intensity wildfire systems.
• This study focuses on bacterial communities in an old-growth pine savanna with a history of frequent prescribed fires.

Purpose of the Study:

• To investigate the composition of ground-level bacterial communities in a frequently burned pine savanna.
• To test hypotheses about differences in bacterial families between burnt and unburnt patches.
• To understand the influence of fire and substrate on microbial communities.

Main Methods:

• Utilized 16S metabarcoding to analyze bacterial communities.
• Examined litter and soil surface substrates in naturally burnt and unburnt vegetation patches.
• Assessed the variation explained by substrate type and fire treatment.

Main Results:

• Litter/soil substrates and fire treatments explained 67.5% of bacterial community variation.
• Shifts in the relative abundance of specific bacterial families were driven by these factors.
• Plant and soil variables were not significantly affected by fire and did not correlate with bacterial community differences.

Conclusions:

• Microhabitat heterogeneity, generated by substrate type and patchy fires, drives bacterial family responses in this pine savanna.
• Prescribed fire management should consider how fire-altered substrate heterogeneity impacts microbial diversity and function.
• Frequent, low-intensity fires are crucial for maintaining the microbial foundation supporting ecosystem processes in fire-frequented habitats.