A little fire did a lot of good for microbes in FIU’s Nature Preserve

• Pine rocklands outside Everglades National Park are vanishing.
• FIU is home to a pine rockland in the middle of its Nature Preserve.
• Pine rocklands depend on fire for a variety of services.
• In 2016 authorities carried out the first prescribed burn on campus.
• After 10 weeks, microbes and fungi helpful for plants were more prominent.

For FIU’s patch of pine rockland, its first-ever controlled burn did a world of good.

Natural pine rocklands have evolved to benefit from naturally occurring fires that periodically burned away invasive plants and excess leaves on the ground, readied seeds for germination and improved soil composition.

Since the founding of the university, the rockland sitting right in the middle of the 11-acre Nature Preserve on the west side of the Modesto A. Maidique campus had been managed only by hand. Volunteers came in and yanked out plants that didn’t belong. But that never truly mirrored the conditions of a natural pine rockland.

In 2016 FIU’s Office of University Sustainability partnered with the Florida Forest Service to conduct a small prescribed burn in the preserve while students were away on Spring Break. While out of control wildfires like the ones currently affecting western states are devastating, prescribed burns are controlled and can be good for pine rocklands.

Once the fire was burnt out, researchers observed how the rockland reacted.

Researchers noted how leaf litter that once covered the ground was charred. They also took soil samples over 10 weeks to look for chemical changes.

What they found was that microbial fungi and bacteria in the soil were more prominent – and that’s good for native plants in the rockland, where soils are notoriously stingy on the nutrients needed for growth.

“One burn at over 40 years with hand management is not an ideal situation,” said Ariel Freidenreich, a Ph.D. candidate in the Agroecology Program who led the study. “If we can see the benefits in such a short time, having prescribed burns every few years might be a good management strategy.”

More research is needed to study the effects of more frequent prescribed fires on small pine rockland forests, which are unique to South Florida, said research principal invesitgator Professor Krish Jayachandran.

These ecosystems once covered a large area. In Miami-Dade County alone, only 2 percent of pine rocklands outside Everglades National Park remain scattered throughout the region with trees standing tall almost like ghostly sentinels – reminders of what South Florida looked like before people replaced nature with homes and strip malls.

The study was a collaboration between FIU’s Office of University Sustainability and the United States Department of Agriculture National Institute of Food and Agriculture National Needs Graduate Fellowship program. It was published recently in the journal Agricultural & Environmental Letters.