Study Finds Natural Wildfires Promote Native Bee Diversity

May 20, 2020

Native pollinators are usually specialized to feed on native flowers.
Credit Lauren Ponisio

According to a recent study, bees in areas with natural fires are more resilient in the face of a changing climate. Not only do these typically small wildfires clear away underbrush and dead trees, preventing the chances of a megafire, but they also provide important signals for native plants to grow, leading to an increase in native plant diversity. 

That diversity supports a wider variety of native pollinators and contributes to their overall health.

"There are lots of floral resources, [but] they tend to be the same floral resources across these big high severity patches, because there's only certain types of plants that can come back after these big high severity fires, and you don't have that heterogeneity at all," said lead researcher Lauren Ponisio. "It's all the same type of habitats."

Ponisio and her team sampled bees and flower species in Yosemite National Park. They took samples from an area known as the Illilouette Basin, where wildfires have been allowed to burn naturally for centuries, as well as areas near tourist hotspots, where fires are fought immediately. In the middle of the two-year study, California experienced a drought. A majority of the flowering plant and bee populations that the team sampled declined. But those in the basin, who had alternate flowers to turn to, suffered far fewer losses.

"We found that the populations in those areas with all this diversity of fire histories around them were also able to withstand the drought better. And going forward, we're expecting with climate change there to be more frequent and higher intensity droughts. We really want our pollinator populations to be able to weather the drought, otherwise, we're going to start losing species," said Ponisio.

Ponisio and her team sampled 164 bee and 71 flowering plant species.
Credit Lauren Ponisio

With diverse resources, pollinators thrive and may also spill over from wildlands into agricultural areas and begin pollinating food crops.

"Studies have found that farms near that edge of natural habitat in the Central Valley tend to have higher yield, because they're getting those natural pollinators coming in and pollinating their fields, "said Ponisio.

Natural wildfires that create a diversity of habitats allow us to lower our reliance on the imported European honey bee, which is experiencing issues of its own.

"European honey bees are amazing pollinators of crops. They're really important to us. But in general, just relying on one species for all of our crop pollination is not long-term sustainable, and so really being able to diversify who we're getting our pollination services from would help ensure that we had continued global food security," said Ponisio.

And one of the best ways to support this transition, according to Ponisio, would be to rethink fire management strategies.

Have a question about this story? Contact the reporter, Ivy Engel, at iengel@uwyo.edu.