Chicago Botanic Garden Fall 2020

The prairie was divided into two sec- tions, with either section burned by fire experts with the Nature Conservancy every five years. They examined the number of heads produced by the plants each year to see how their pre- scribed burns were affecting the num- ber of flowers being produced and how many flowers got pollinated. The remarkable thing the researchers learned was that the pollination was so much better after fires too. In most years, many flowers did not produce seeds because they were not pollinated. However, in the year right after a fire, pollination improved and seed produc- tion nearly doubled. “In order for purple coneflowers to ex- ist on that prairie for the long haul, they have to survive and reproduce. We learned that fire is essential for repro- duction. A healthy population is one that will be resilient in the face of ad- versity. Fires keep populations healthy,” said Wagenius. In addition to a healthy plant popula- tion, plant diversity plays an important role for native prairies. “If there are no fires, then plant species disappear. When they’re no longer there, you get lower diversity. Having many species keeps it a special place and makes it nice to look at. The animals that live there need diversity too. Some animals only eat one species of plant, so if that plant is gone, that animal is gone,” said Wagenius. For Wagenius and his team, there’s more to learn about prairies and fires. “We found this result about one spe- cies, Echinacea angustifolia , and we ar- gue that this is a general phenomenon, but we don’t know that,” he said. “This is a new idea—that fires increase repro- duction. One of our ideas is to try it out and see if this same mechanism— the effects of fire on reproduction—is at work in other species. I’m in it for the long haul. I love prairies, so I’m go- ing to keep doing research.” Learn more chicagobotanic.org/research     