How microbes return after fires

Bushfires and wildfires make drastic changes to the plants, animals, insects and soil living in an area. But they also change an ecosystem’s microbial life.

A study published in mSystems has mapped how microbes like bacteria and fungi return to 2 US ecosystems after getting burned, which will help with overall understanding of how burnt regions begin to recover.

“We know with climate change and human activity we’re disturbing our ecosystems more and more,” says lead author Kristin Barbour, a PhD student at the University of California, Irvine.

“Microbes, especially those in the surface soil, perform a number of really key ecosystem processes, like carbon and nitrogen cycling.”

Barbour initially planned to study the effects of drought on microbial systems, but a wildfire burned through one of the field sites proposed for study.

“We wanted to take advantage of this disturbance, especially since wildfire is becoming more frequent in many parts of the world,” says Barbour.

The researchers spent a year collecting and analysing the microbial populations in a semi-arid grassland and a coastal scrub, both of which had been affected by fire.

They put bags filled with burned leaf litter out at each site: half were porous and allowed  microbes to enter, while the other half were closed as controls. They also filled some bags with glass slides to collect microbes in each group.

These bags, put out at 5 different points over a year, allowed the researchers to track microbe dispersal.

Wind and air seemed to play a big role in both bacteria and fungi dispersal, and soil under leaf litter (bulk soil) was important for bacterial movement.

“There’s a lot of exciting work being done right now, looking at dispersal and at microbial communities out in the environment,” says Barbour. 

Subscribe to our quarterly print magazine

Please login to favourite this article.