When Rich Hatfield was a graduate student studying Conservation Biology, Robbin Thorp was considered “the grandfather of bumblebee conservation” and had been conducting a long-term study of sites between Mt Shasta and Mt Ashland, in Northern California and Southern Oregon. Over the course of just two to three years, Franklin’s bumblebee (Bombus franklini) and the Western bumblebee (Bombus occidentalis) “went from being some of the most common animals to literally non-existent,” Hatfield recounts.
The experience must’ve felt something like the shock Emilie Blevins described as she’s more recently witnessed freshwater mussel bed die-off’s, and not surprisingly, Thorp worked to wave the red flag in response.
Thorp’s determination “inspired a lot of the work I do now,” Hatfield says. Hatfield is also now a Senior Conservation Biologist, and the lead of Bumblebee Conservation Programs with the Xerces Society, and in this role is working with partners and citizen scientists to find if there are any remaining populations of these bees in this range, and to study bumblebees in the Pacific Northwest more broadly.
Within the approximately 3,600 species of bees that call North America their native home, about 50 are bumblebee species, or “roughly one percent of North America’s bee diversity is made up of bumblebees,” Hatfield says. Admittedly, “bumblebees aren’t really a great poster child for the bees of North America.” However, their role as a pollinator, the relative ease for non-scientists to recognize them, and the direct impact humans have played in their populations’ health has brought just attention to their plight.
While most native bees on our continent take on a solitary lifestyle in grand contrast to the colonial honeybees most humans are more familiar with, the life of bumblebees take a middle ground approach. Hatfield explains: “they do have queens, they do have workers, but the way that they differ from a honeybee colony is that…most of the colony actually dies off [each year] and it’s only queens that survive the wintertime by hibernating…then start a new colony every spring.” Hibernation may occur in underground nests, in abandoned rodent burrows, or sometimes on the surface of the ground nestled in thatch grasses, or even high above the ground in tree cavities or old bird nests.
In contrast, honeybees survive the winter by eating the honey they made earlier on. And while a honeybee queen may live five to seven years, a bumblebee queen just gets one year to carry out this cycle.
Perhaps in part because of this short life cycle, bumblebees are especially vulnerable to impacts to their habitat and disease. Since Thorp’s observance of Franklin’s and Western bumblebee declines, as well as parallel declines seen in bumblebee species on the east coast, it is largely thought that a fungal pathogen, Nosema bombi, is at fault, after it was spread and amplified in the wild through the release of commercial bumblebees.
You see, some bumblebee species are bred specifically to pollinate food crops, like tomatoes, that are grown in greenhouses. “In the mid-1990’s there was an outbreak in these laboratory colonies, but there was some resistance because they were living in laboratories and had some support from scientists,” Hatfield says. “Then these [resistant] bumblebees were shipped all over the country and spread and amplified this pathogen to unsuspecting wild bees — bees can fly in and out of a greenhouse fairly easily.”
The result? Western bumblebees, which used to be one of the top four most common bees in the Willamette Valley are no longer found in the parts of their historic range west of the Cascades, and a Franklin’s bumblebee hasn’t been spotted in its more restricted historic range since a rare sighting occurred on Mt Ashland in 2006.
Franklin’s Bumblebee Listing: The Search Expands
First petitioned in 2010, Franklin’s bumblebee was officially listed as endangered by the federal government in 2021. But at the moment, this legal protection needs to be taken with a grain — or two — of salt.
“Right now, the listing doesn’t really do anything,” Hatfield says with a laugh, perhaps out of exasperation. “We don’t have any [recent] observations of this species, so there are no regulatory actions that will take place until we actually find the species.”
What the listing does do is further awareness and bring additional resources to survey efforts so that “hopefully we can find a remnant population of this species. Then at that point is when the different principles of the Endangered Species Act would come into play in terms of providing regulatory protection for the bee.” However, such a task ahead is not without precedence — in the past species have gone undetected for long periods of time, have been re-discovered, and eventually recovered through conservation efforts. One example of this kind of pattern has even occurred in the Willamette Valley. Bradshaw’s lomatium (Lomatiumbradshawii) – a plant found in wet prairies and formerly listed as endangered – was re-discovered in the 1980’s and subsequently restored to the point of recovery and delisting.
But with such a rugged, remote historic range in the Siskiyou Mountains, searching for Franklin’s bumblebee is a bit akin to “finding a needle in a haystack,” Hatfield says. This is a task that requires strategy.
Following the listing, partners identified high potential zones based off historical observations of Franklin’s bumblebee, mapped habitat suitability — places with good flowering resources throughout the summer — in the surrounding area, and “essentially flagged large polygons where we think would be good areas to conduct surveys for this species.”
Even before Franklin’s achieved the recognition ESA listing provides, bumblebee survey efforts were already ramping up via a citizen science project called the Pacific Northwest Bumblebee Atlas. This project covers Oregon, Washington, and Idaho, dividing the area within these states into equal area grid cells in which volunteers deploy themselves to conduct standardized surveys in hectare plots over the summer season. Over a 45-minute period, the surveyors cover the entirety of their plot and try to capture every bumblebee they see in nets. The bees are then placed in jars in a cooler with ice to induce a state of diapause. Once the bees are asleep, detailed photographs can be taken and later submitted to the community science website Bumblebee Watch, in which trained experts verify the species identification. All bees captured are released back to the wild.
Last summer, hundreds of volunteers — including professional photographers, avid gardeners, and retired academics — got involved in the effort. Without so many people, Hatfield suspects the dozen or so bumblebee researchers in Oregon and California could maybe cover just 50 sites a season.
“Increasing the boots on the ground definitely increases the probability of encountering this species,” Hatfield says.
And, as a huge side benefit of such thorough and expansive surveying for Franklin’s bumblebee, information is being gleaned about other species encountered and their habitat/flower associations. “That helps us to understand better which plant species are supporting which bees on the landscape, and in turn helps us to make better management recommendations to the Forest Service and the BLM [Bureau of Land Management] and Fish and Wildlife Service as they’re restoring habitats,” Hatfield says. “We’re helping [federal landholding agencies] to put these flowers on the ground which are supporting these bees.”
Western Bumblebee Listing & the Continuing Grind
In specific, the information gathered in the name of surveying primarily for Franklin’s bumblebee is contributing to better understanding the Western bumblebee, which is currently undergoing a species status assessment, or 12-month review, before a listing decision is made by the USFWS.
“We’ve learned a lot about where this species [Western] is found, what flowers are important, where its’ strongholds are and where it seems to be struggling,” Hatfield explains. “All of this helps us identify target areas for restoration.”
Another effort underway this summer will look at the less-studied side of the bumblebee’s life cycle – nesting and overwintering. While planting specific flowers to support associated pollinators is a worthy effort in its own right, Hatfield says “it may not be that flowers are the problem. The problem might be that they don’t have anywhere to overwinter anymore or we’re disturbing their overwintering in some way that’s killing them.” To address this gap in understanding, scientists are conducting a study on Mt Hood to look for nests and to try following queen bumblebees to their overwintering locations.
“You just got to keep grinding,” Hatfield says. “While the day-to-day change is quite slow, when you step back and look at the larger landscape of pollinator conservation, we’ve come a long way in the last 25 years… 25 years ago if I were to teach a bumblebee workshop, I would’ve had to fly people from all over the world to fill a room,” he says with a laugh. “I’m not exaggerating, it would have been hard to get people to come listen to a talk about bumblebees. Now I can advertise a talk on bumblebees on Zoom and I can get 400 people to register for it… it’s come a long way.”
Resources & Ways to Help
- Knowledge is power: https://www.pnwbumblebeeatlas.org/recorded-trainings.html
- Join the survey efforts: training workshops for next summer’s surveys will take place in early May and early June https://www.pnwbumblebeeatlas.org/live-events.html
- Enhance your garden: https://xerces.org/bring-back-the-pollinators
Support for the Little Things
While the challenges freshwater mussels and native bumblebees in Oregon and across their ranges in the West may seem daunting and perhaps in conflict with human activity, it is important to note that Americans’ support for the Endangered Species Act has remained strong in the past two decades and even transcends political ideology. A 2018 study found that about four out of every five Americans support the ESA, and even amongst members of special interest groups that would seem at odds with the ESA maintain 68% or greater support for the law.
As Blevins put it, part of what keeps her motivated in freshwater mussel conservation is that “most people really don’t want to harm other species and are interested in living in landscapes that are good for everyone.”
And further than just supporting whatever legal actions come about, people beyond scientists are willing to put their time and energy towards conservation. Hatfield says, “people care about this [bumblebee] issue pretty deeply, I think because of the ecosystem services and the relationship to food people understand why this matters… people are hungering for this knowledge and ‘what’s the right thing to do?’… Seeing the number of people that have engaged in these projects, the number of hours they have dedicated as volunteers over the last four years is really heartening.”
Hatfield admits he worries that efforts are “not fast enough — I always worry that it’s not enough, that we’re fighting battles with organizations with resources and war chests that are much larger than ours.” But, he maintains, “I think if we can continue to build public sentiment in the right way around these issues then we stand a chance.”
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By Ari Blatt
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