PHOTO: Coneflowers.

60-Second Science: Prairies Need Fire

PHOTO: Becky Barak.Becky Barak is a Ph.D. candidate in Plant Biology and Conservation at the Chicago Botanic Garden and Northwestern University. She studies plant biodiversity in restored prairies, and tweets about ecology, prairies, and her favorite plants at @BeckSamBar.

A dark, stinky plume of smoke rising from a nature preserve might be alarming. But fire is what makes a prairie a prairie.

A prairie is a type of natural habitat, like a forest, but forests are dominated by trees, and prairies by grasses. If you’re used to the neatly trimmed grass of a soccer field, you may not even recognize the grasses of the prairie. They can get so tall a person can get lost.

Prairies are maintained by fire; without it, they would turn into forests. Any chunky acorn or winged maple seed dropping into a prairie could grow into a giant tree, but they generally don’t because prairies are burned every few years. In fact, fossilized pollen and charcoal remains from ancient sediments show that fire, started by lightning and/or people, has maintained the prairies of Illinois for at least 10,000 years. Today, restoration managers (with back up from the local fire department), are the ones protecting the prairie by setting it aflame.

PHOTO: Chicago Botanic Garden ecologist Joah O'Shaughnessy monitors a prairie burn.
Garden ecologist Joan O’Shaughnessy monitors a spring burn of the Dixon Prairie.
PHOTO: New growth after a prairie burn.
New growth emerges a scant month after the prairie burn.

Prairie plants survive these periodic fires because they have incredibly deep roots. These roots send up new shoots after fire chars the old ones. Burning also promotes seed germination of some tough-seeded species, and helps keep weeds at bay by giving all plants a fresh start.

Read more about our conservation and restoration projects on the Chicago Botanic Garden website. Want to get involved in our local ecosystem conservation? Find your opportunity with Chicago Wilderness.

Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This is our third installment of their exploration.

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3 thoughts on “60-Second Science: Prairies Need Fire”

  1. Prairies need hoof animals. It’s really sad to watch how poor the so called “restored” prairies look. The chemical degradation (fire) can’t replace the animals and biological degradation they make. The fire damages more than it restores. Sad, sad, sad… You guys could get your act together and start SEEING this.

    1. Fire is an important management tool that helps to keep prairie vegetation healthy. It is particularly important for the control of woody species that might otherwise become too prevalent. Where possible, the reintroduction of bison grazing can help to restore the mosaic of interacting patches. This requires relatively large expanses of intact habitat. Mowing and treatment with grass-specific herbicides may provide some of the benefits of bison when reintroduction is not appropriate for the site. Other hoofed animals have different effects, sometimes detrimental to the forbs in particular, because they have different grazing behaviors that may not be conducive to achieve the management objectives.

  2. Although prairies were not created by fire, they have been able to persist as very rich and diverse plant and animal associations for thousands of years with fire as part of their ecology. Biologists who have looked into the role of large hoofed grazers in the prairie areas east of the Mississippi River (see suggest caution when it comes to introducing those animals to our better quality remnant prairies. Fire is definitely a disturbance, but most prairie plants and animals have evolved adaptations to survive along with fire. That is not to say that, as managers of these small fragments of a once vast ecosystem, we should use fire wisely.

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