Bringing the buzz back to Pacific Northwest forests
Lauren Ponisio, assistant professor of biology, is working with her team to revive declining bee populations in Pacific Northwest forests.
Examining Potential Floral Enhancements in Harvested Forests for Promoting Bee Populations, and the Barriers and Incentives to Adopting Bee-friendly Practices
Bee populations in North America have been on the decline for decades. A team of researchers in the College of Arts and Sciences has been working to find a way to help them bounce back by reintroducing native plant species throughout post-wildfire timber plantations in the Pacific Northwest.
“Our main goal is to determine whether we can use these native plant enhancements in industrially managed tree plantations to promote healthy bee populations,” says Lauren Ponisio, assistant professor in the Department of Biology.
Funded by a grant from the US Department of Agriculture, Ponisio leads a team of graduate students and members of the undergraduate Environmental Leadership Program to find a way to turn former tree plantation environments into places for bees to foster more native plant diversity.
Assistant Professor of Biology Lauren Ponisio
I’ve always wanted to study pollinators, and particularly how they interact with agriculture. In Oregon, a large percentage of our forests are managed to produce forest products, such as lumber.
Lauren Ponisio, professor of biology
The state’s timber harvesting cycle has an impact on native plant populations, which in turn affects bees. Foresters use herbicide in new timber stands—groups of trees within a forest that are capable of producing timber—to reduce competition with other plant species, often applying a second round of herbicide during the third year of growth. Most of Oregon’s forests have gone through at least a couple of cycles of this harvesting process.
Working in collaboration with the National Council for Air and Stream Improvement (NCASI), a nonprofit organization associated with the timber industry, Ponisio’s team has connected with timber industry leaders who are interested in bee conservation.
“Oregon has four species of bumblebees that are either listed under the Endangered Species Act or have been petitioned to be listed,” Ponisio says. “There’s a lot of interest in understanding how we can help these populations before they get listed.”
Ponisio's team plants native species near slash-burn piles.
Ponisio’s research focuses on the forests burned by the Holiday Farm Fire in 2020. The fire, which burned about 173,000 acres, provides enough space for replication within their research. In a normal year, there are only a limited number of clearcuts in an area, but the aftermath of the fire led to a higher-than-usual timber harvest, providing an opportunity to restore bee populations over thousands of acres.
Biology graduate student Rose McDonald leads a team of undergraduates and technicians who are identifying locations burned during the Holiday Farm Fire and enhancing them with native seeds.
“At the same time, we will learn more about how plant and pollinator communities are rebuilding post-fire,” she says.
During the fall, Ponisio’s team travels to slash-burn piles—large piles of debris from clearcut areas that are then burned—to plant native species.
“When they burn the piles, it's like a restoration site preparation treatment where they’re burning out the invasive seed bank,” Ponisio said.
The following spring and summer, they return with aerial nets and catch bees from the native flowers. The team then records which bees visit the site, looking for diversity and abundance within the bee population.
“Though success varies depending on management intensity, we’ve seen that our native plants can do really, really well and attract a ton of bees,” Ponisio says. “It’s also been interesting to see that, generally, there are a lot fewer bees in these really large fire areas than we would have expected, given how much potential habitat there is.”
Ponisio works on a project on private land burned by the Holiday Farm fire.
These findings have led Ponisio’s team to an array of new questions, specifically about the effects of the fires themselves on bee populations. Historically, Oregon’s fires were much smaller and of mixed severity compared to more recent blazes, which have been hotter and larger.
Ponisio speculates that it may take years for bee populations to re-establish—but plant diversity is a big first step.
“The western US is a global hotspot for bee diversity, so if we’re doing conservation here for these different bee species, we’re actually having a global impact on bee conservation,” she says. “Pollinators are responsible for the majority of our nutrition in terms of agriculture and bee populations are declining. But, if we can add plant diversity back into the system, the bees would love it.”
