And bumble bee expert Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis, was a part of it.
The beleaguered rusty-patched bumble bee, Bombus affinis, is now listed by the U.S. Fish and Wildlife Service as an endangered species, the first bee in the continental United States to be listed under the Endangered Species Act.
Thorp, co-author of Bumble Bees of North America: An Identification Guide (Princeton University) helped sound the alarm.
He co-authored a 2010 petition seeking an endangered status for Bombus affinis. The Xerces Society of Invertebrate Conservation, along with Thorp and others, submitted the petition to the U. S. Fish and Wildlife Service in 2013. In 2015, agency officials agreed to consider it. In 2016, they proposed protection. Then on Jan. 10, 2017, the Fish and Wildlife Service listed the rusty-patched bumble bee as an endangered species.
Other key players in making this all happen included natural history photographer/filmmaker Clay Bolt and his friends at the Day's Edge Productions, which created the award-winning film, A Ghost in the Making: Searching for the Rusty Patched Bumble Bee with support from the Xerces Society and others. The result: nearly 200,000 persons signed a petition seeking endangered status for the bee.
The rusty-patched bumble bee was once found in 28 states in the eastern and upper midwest United States, along with the District of Columbia and two Canadian provinces. Since the late 1990s, however, its population has declined by nearly 90 percent, according to Sarina Jepsen, director of endangered species for the Xerces Society.
"The rusty patched bumble bee is threatened with extinction," Jepsen wrote in the petition. "Possible causes of its decline include pathogens, habitat loss or degradation, pesticide use, and climate change. Reduced genetic diversity, which could be a result of declining, isolated populations caused by any of the aforementioned factors, likely also threatens this species with extinction. Furthermore, existing regulations are wholly inadequate to protect this species."
Jepsen described bumble bees as "iconic pollinators that contribute to our food security and the healthy functioning of our ecosystems."
Enter Clay Bolt who set out to find, photograph and document the critically imperiled bumble bee. He moved from state to state, habitat to habitat, museum to museum, meeting with scientists and conservationists. Finally, he found the living breathing rusty-patched bumble bee in the University of Wisconsin arboretum.
Bolt related that he first became aware of the plight of the rusty-patched bumble bee while looking at specimens in the collection at Great Smoky Mountains National Park. "There was a stuffed passenger pigeon in the same room, frozen in time, but no longer among us in nature," he said. "It was once the most numerous bird on the planet and then it was no more. This has always haunted me. I decided then that I had to do everything in my power to attempt to bring more attention to this beautiful little bee before it went the same way."
With friends from Day's Edge Productions and the Xerces Society, Bolt made the film about the bee, helped develop the petition, and spoke on Capitol Hill and other high-profile events to spotlight its plight. "Through all of this, I kept thinking back to seeing this amazing little animal in the field," Bolt said. "Watching it fly. Witnessing it do what it had been doing for thousands of years. It had no idea that its fate was in our hands."
"I am just so encouraged and grateful for the public's outcry in support of this species," Bolt said. "This was an effort that would have never been possible without so many people working together to see it through. I am grateful that my images played even a small part in this historic occasion. These are the moments that make all of the hours of work and worry worthwhile."
How many other bumble bees should be listed as endangered? "That's difficult to answer, mainly due to a lack of good information," said Thorp. "Most of our bumble bee species seem to be doing well according to our most recent assessments. But at least one eastern cuckoo bumble bee may be declining because its host bumble bees have declined. About a quarter of our bumble bees may be at risk, but we need more information. One that used to be common here in the Central Valley, Bombus sonorus, basically disappeared from our area about a dozen years ago, but it is doing well in the southern part of its range in southern California and Arizona."
Meanwhile the U.S. Fish and Wildlife Service is reviewing three other species of bees for possible inclusion as endangered. They include Franklin's bumble bee, the western bumble bee and the yellow-banded bumble bee.
Thorp, who has been monitoring Franklin's bumble bee, Bombus franklini, since 1998, hasn't seen the bumble bee in 10 years within its five-county range of southern Oregon and northern California. He doesn't want to say the "E" word--extinct. Not yet. He thinks this may be the year he'll find it.
The emeritus professor, who retired in 1987, was the last surviving member of the original entomology faculty.
Dr. Bacon chaired the department (now the UC Davis Department of Entomology and Nematology) from 1967 to 1974. In 1964, Mrak appointed him to spearhead the UC Davis conversion of the two-semester system to four quarters.
Dr. Bacon was chair of the entomology department when it moved to the newly constructed Briggs Hall in 1972. An appreciative faculty presented him with a plaque thanking him for his “stewardship during a period when new teaching and research areas were initiated and when a great increase in the numbers of students enrolled in the department occurred has contributed significantly to the future of the department and to entomology.”
As a 41-year UC agricultural entomologist, Dr. Bacon specialized in the biology, ecology and population dynamics of insects associated with field crops. He pioneered the biological control course on the UC Davis campus and was instrumental in forming the Plant Protection and Pest Management Graduate Group. He is credited with co-authoring the term, “integrated pest control.”
Colleague Norm Gary, emeritus professor of entomology, said: "The last time I visited with Oscar was this past year when he attended a music performance by my band at the senior home where he lived the last years of his life. He was amazingly sharp and active at 96!"
“When I first arrived in Davis in 1962 Oscar gave me an orientation tour to see California agricultural activities and visit his field research projects just north of Woodland," Gary said. "Years later, after he became department chair, I was impressed and appreciative that he actually took time to visit my active field research activities with bees near Dixon. Oscar was very supportive in many ways to our Entomology faculty and highly regarded as a professional. He was always cheerful, thoughtful, considerate, and fun to be with, whether at morning coffee breaks, faculty meetings or at Christmas parties. He was an amazing man in all respects. He enriched all of our lives, professionally and socially.”
Emeritus professor Robert Washino, former chair of the department and former associate dean, UC Davis College of Agricultural and Environmental Sciences, recalled: “I was appointed to the faculty in Entomology during the Bohart to Bacon transition period as department chair and so my interaction with Oscar dealt mostly as a newly appointed junior faculty. However, during all the years since then as a colleague and friend, I've never, ever heard Oscar make an unkind remark about anyone in teaching/advising, research and administration.”
Said distinguished emeritus professor Robbin Thorp, who collaborated with Bacon on alfalfa leafcutter bees in the mid-1960s: "I always had a great deal of respect and admiration for Oscar as a meticulous scientist, outstanding teacher, leader and person. Oscar and his research associates, Dick James and Walt Riley, in collaboration with a grower, Dan Best in the Woodland area, designed and tested shelters to provide shade and ventilation for these relatively new pollinators for alfalfa seed production. The shelters were successful.”
“Oscar and his crew also tested pesticide effects on these bees and discovered a number of biological traits important to their management as commercial pollinators," Thorp said. "Oscar co-authored the first Cooperative Extension publication on the alfalfa leafcutting bees with several of us.”
Dr. Bacon, who humbly said of himself: “I'm the jack of all trades and master of none,” pursued many diverse interests. He was not only agriculturist, entomologist, researcher, professor, administrator, but a mechanic, furniture builder, boating enthusiast and ag history docent. He restored antique cars and boats, from rustic Model T's to a 1964 mahogany Chris-Craft cabin cruiser. As a wood carver and artist, he crafted furniture and carved birds.
Born Nov. 8, 1919, Oscar grew up in Sanger, Fresno County on a 60-acre family farm. He was an only child. Oscar harvested grapes, figs and peaches, drove tractors, raised 4-H pigs and renovated Model T's.
“Back then it seemed like nearly every farm had an old worn-out Model T along the fence lines,” he recalled in a feature story published in 2009 on the UC Davis Entomology website. “A boyhood friend from a neighboring ranch and I would give a farmer a couple of dollars for his car and then restore it.” The Tin Lizzies purred back to life.
Young Oscar attended school in a two-room schoolhouse; he recalled that grades one through four shared one room, and grades 5 to 8, the other.
Nature fascinated him. “I collected insects and watched birds and mammals and collected rocks and minerals.”
Oscar graduated from Sanger High School, Reedley Junior College and Fresno State College, majoring in zoology. He planned a career as a ranger naturalist with the National Parks Service, but the federal agency had no openings. So he accepted a position with the USDA Dried Fruit Insect Laboratory, Fresno, as a field aide.
It proved to be a two-year stint. In 1943, his boss steered him toward entomology and encouraged him “to get a degree” at UC Berkeley and return to the USDA.
Oscar went on to earn two degrees from UC Berkeley: his master's degree in entomology in 1944, following a year of study, and his doctorate in entomology in 1948.
His major professor at UC Berkeley was the legendary entomologist and aphid specialist Edward O. Essig (1884-1964), but Oscar worked more closely with another accomplished entomologist, Abraham Michelbacher (1899-1991). “Abe was like a second father to me,” he recalled.
Dr. Bacon landed his first full-time job in entomology in 1946 as an associate in the agriculture experiment station. Upon completing his Ph.D., he became a junior entomologist and instructor. As a Ph.D., his starting salary was less than $5000 a year.
His first major crop work: controlling aphids in spinach. Then it was on to other crops, including sweet corn, seed alfalfa, potatoes, small grains, tomatoes and melons.
“In 1953 I had the opportunity to come to Davis to develop my own programs,” he related. “I was extremely grateful for that opportunity.” At the time, the UC Berkeley Department of Entomology offered a two-year ;Farmers' Short Course' on the Davis campus for students interested in farming. The career-oriented program was phased out in 1959.
“Stanley Freeborn (first chancellor of UC Davis) and his wife welcomed us to campus,” he said. “He was very gracious--a very nice person.”
At the time, the original faculty members included Richard Bohart (1913-2007), insect systematics and Harry H. Laidlaw Jr. (1907-2003), apiculturist. Today the Richard Bohart Museum of Entomology and Harry H. Laidlaw Jr. Honey Bee Research Facility bear their names.
It was an era when secretaries typed manuscripts from handwritten notes; “office space” consisted of temporary buildings or renovated garages; and faculty (usually all male) wore a tie and jacket in the classroom. It was also a period of rapid growth and steady challenges.
In 1964 UC President Clark Kerr announced the plan to convert the entire UC academic system from two semesters to four quarters. UC Davis Chancellor Mrak asked Oscar Bacon to head the conversion efforts at Davis. “We had 1687 courses, and they all had to be reviewed and shortened from 15 weeks to 10 weeks,” recalled Bacon. Remarkably, the conversion took only a year.
Oscar Bacon was considered UC's “No. 1 Alfalfa Seed Insect Man.” In 1987, the California Alfalfa Seed Production Board recognized him for 13 years of service. In 1975, the Pacific Seed Association, based in Los Angeles, named him “Man of the Year.”
Integrated pest management specialist Frank Zalom, distinguished professor of entomology and former vice chair of the department and a past president of the Entomological Society of America, said he has long admired Bacon as an advocate for agricultural entomology research.
Said Zalom: “Many entomologists may not appreciate that the credit for first using the term ‘integrated control' is generally attributed to Abraham Ezra Michelbacher and Oscar Bacon, who in a 1952 paper in the Journal of Economic Entomology on control of codling moth mentioned the importance of ‘considering the entire, entomological picture in developing a treatment for any particular pest.' ”
Michelbacher and Bacon developed an effective integrated control program of the important pests of walnut, Zalom said. They “described methodologies for selection, timing and dosage of insecticide treatments for the codling moth to preserve the parasitoids of the walnut aphid that had achieved biological control following their introduction to California.”
“This was an important step in the development of the IPM paradigm and is still relevant,” Zalom said. "I also appreciate his role in the development of the Plant Protection and Pest Management Graduate Group at UC Davis that produced many students who are working as pest management practitioners across the state and across the country.”
Dr. Bacon is survived by his wife, Barbara, of Davis, and a daughter, Bonnie Krisiak, son-in-law Steve Krisiak and granddaughter Stephanie Krisiak, all of the Sacramento area. He and his first wife, the late Dorothy Flagg Bacon, raised three daughters, Beverly and Gayle (now both deceased), and Bonnie.
Some of the highlights of his life:
Field-Oriented Entomologist: He worked on field crops, including seed alfalfa, potatoes and small grains, establishing a state, national and sometimes global presence (potato crops in Bolivia). He targeted the lygus bug, the main pest of alfalfa seed production. “The lygus bug has no natural enemies, so we had to depend on insecticides. Then the lygus bug developed resistance to those insecticides.” He developed economic thresholds, determining at what point the cost of pest damage exceeds the cost of pest control.
In 1944 Bacon showed that Catalina cherry moth, which infests Catalina cherry and large galls of the blue oak, is an important pest of walnuts in the Sacramento Valley. Today it attacks certain varieties of walnuts throughout the state.
Research: Bacon researched whether an 18-acre field of alfalfa seed would show the same yields without insecticides. Would predators and parasites be able to control the pests? His three-year study showed the organic field yielded 200 to 300 pounds per acre instead of the normal yield of 600 to 800. “Agricultural chemicals will be necessary on certain crops for some time to come,” he concluded. “The world's food supply would certainly not exist without the control measures as we know them today.”
Teaching and Advising: As a devoted teacher, Dr. Bacon developed “The Natural History of Insects” into one of the most popular undergraduate classes on the UC Davis campus. He initiated the biological control course at UC Davis. He advised scores of undergraduate and graduate students. He helped launch the Plant Protection and Pest Management Graduate Group Program. When he retired, Bacon received a plaque from the graduate program applauding his dedication, perseverance and accomplishments. It's one of his cherished awards “because it's from the students.”
Administration: His role as a chancellor's assistant for UC Davis Chancellor Emil Mrak included the project of converting the UC Davis two-semester system to four quarters: completed in one year. As chair of the UC Davis Department of Entomology from 1967 to 1974, he moved his department to the newly constructed Briggs Hall in 1972. Upon his retirement as chair, the faculty presented him a plaque thanking him for his “stewardship during a period when new teaching and research areas were initiated and when a great increase in the numbers of students enrolled in the department occurred has contributed significantly to the future of the department and to entomology.”
Heidrick Ag History Center: In 1996, Bacon began volunteering at the Hay's Antique Truck Museum, Woodland, which later merged with the Heidrick Ag History Center. He's known as “the friendly docent with first-hand knowledge of the farm equipment.” In his boyhood, he drove tractors similar to those on display. Today he volunteers once a week, more on special occasions.
U. S. Coast Guard Auxiliary: Bacon took up boating and fishing in 1956. In 1975, he joined the U.S. Coast Guard Auxiliary. In December 1987, Bacon was elected commodore of a district that encompassed northern California and parts of Wyoming, Nevada and Utah. He taught boating safety, inspected crafts and patrolled the Delta waters for more than 25 years. The U.S. Coast Guard, the parent organization, awarded him a citation in 1988, praising his accomplishments and dedicated support.
Artist: In 1990, Bacon enrolled in a woodworking class in Sacramento, and carved birds from basswood, sugar pine and tupelo blocks, and textured and painted them. “There's a bird in every block,” he recalled. “It's tedious and time consuming but very rewarding. I've never been interested in making them for sale.” His favorites include an American kesterel sparrow hawk that he carved in 1997. His other favorites include a white-breasted nut hatch, white crown sparrow, California quail, stellar jay and a redwing blackbird. He's also completed other works, including a replica of a team of Clydesdale horses pulling a Anheuser-Busch wagon. “No, the company has never seen it,” he said.
Restoration: Bacon advanced from restoring rustic Model T's in his childhood to renovating antique cars and boats. At one time he owned four boats and five cars. One of his prized possessions: a 30-foot Chris-Craft cabin cruiser, a 1964 model that he restored in 1973 and sold in 2008. He has also crafted furniture for his home and family. Eric Mussen, Extension apiculturist emeritus, still marvels at how Bacon could tuck his 6-foot, 4-inch frame inside his Triumph TR3, a tiny British sports car he restored.
All Things Entomological: Bacon served as president of the Northern California Entomology Society and held membership in the Entomological Society of America and the Pacific Branch of ESA.
Cooperative Extension: In 1987, the UC Davis Cooperative Extension (CE) group honored him for his public service, naming him “the best problem solver.” The group included CE specialists Vern Burton (deceased) and Eric Mussen; research associate Wayne Johnson (deceased); and administrative assistant Shirley Humphrey.
(Editor's Note: At his request, the family will not be holding a memorial service."
A program on “Bees and Climate Change” is set from noon to 1:30 p.m., Wednesday, Oct. 12 in the Häagen-Dazs Honey Bee Haven, located on Bee Biology Road, west of the central campus.
The event, free and open to the public, is part of the 2016-17 Campus Community Book Project, spotlighting Raj Patel's Stuffed and Starved: The Hidden Battle for the World Food System.
Christine Casey, manager of the honey bee haven, will speak on “Climate Change and the Bee Garden," and Robbin Thorp distinguished emeritus professor of entomology, UC Davis Department of Entomology and Nematology, will cover "Effects of Climate Change on Native Bees."
The haven, part of the UC Davis Department of Entomology and Nematology, was installed in the fall of 2009 following a generous donation from Häagen-Dazs, known for its premium ice cream. Approximately half of the company's flavors depend on bee pollination.
The Oct. 12th event is part of a series of tours and open houses scheduled the week of Oct. 11-13.
Tuesday, Oct. 11
Exploring Horticulture Innovations
Noon to 1:30 p.m., Horticulture Innovation Lab Demonstration Center
Tour the low-cost, agricultural technologies that UC Davis researchers are using around the world. Edible plant giveaway to the first 20 visitors.
Wednesday, Oct. 12
Student Farm Tour and Harvest
9 to 10:30 a.m., Student Farm
Join the Student Farm for a special tour and harvest demonstration. Campus and community members are all welcome!
Thursday, Oct. 13
Arboretum Edible Campus Project and World Food Day Information Session
Noon to 1:30 p.m., Plant and Environmental Sciences Salad Bowl Garden
Tour the Salad Bowl Garden and learn more about the Arboretum Edible Campus Project in celebration of World Food Day, which will be Sunday, Oct. 16.
Another upcoming event affiliated with the Campus Community Book Project will feature agricultural entomologist Christian Nansen of the UC Davis Department of Entomology and Nematology. He will speak on "Urban Food Production in the Digital Age--Local Empowerment and Sustainability, on Wednesday, Jan. 18 from noon to 1 p.m. in the Memorial Union.
See more events here.
The Campus Community Book Project (CCBP) was initiated to promote dialogue and build community by encouraging diverse members of the campus and surrounding communities to read the same book and attend related events. The book project advances the Office of Campus Community Relations (OCCR) mission to improve both the campus climate and community relations, to foster diversity and to promote equity and inclusiveness.
For more information on the Campus Community Book Project, visit ccbp.ucdavis.edu./span>
“Flowers feed the world, keep us healthy and make us smile,” says Buchmann, who received his doctorate in entomology in 1978 from UC Davis and is a longtime pollination researcher and adjunct professor in the departments of entomology and ecology and evolutionary biology at the University of Arizona.
But flowers, especially red roses, the most commonly gifted flower on Valentine's Day, can't hold a candle to what most people never think about—that flowers feed the world, thanks primarily to honey bees, bumble bees, syprhid flies and other pollinators.
“Because pollinated and fertilized blossoms turn into nutritious fruits and seeds, these invaluable foodstuffs keep the world's 7.2 billion people from starvation,” Buchmann points out. “These resulting fruits also feed birds, bears and other wildlife.”
And flowers make us a smile. “Give someone flowers, and they flash a genuine Duchenne smile,” Buchmann promises. “Rutgers psychologist Dr. Jeanette Haviland-Jones has infused subliminal amounts of rose and gardenia vs. manmade scents into room air. Subjects use more enjoyment words and were more likely to approach or touch a stranger when the floral scents were present. Flowers may counteract the semiochemicals for fear, anger and anxiety that humans seem to constantly be emitting.
Other reasons for flowers, all detailed in his book, just released Feb. 9 in paperback by Simon & Schuster, include:
- Tasty and Nutritious. “Although the calories from starchy cereals and grain crops feed the world, we enjoy and need the ‘nutraceuticals' and antioxidants inside colorful cranberries, blueberries, oranges and apples,” he says. “They keep us healthy and happy.
- Edible flowers. “Some flowers--that is, roses, some marigolds--are great as edible garnish and foods.” His book relates “which ones can be eaten and what they taste like."
- Humans might never have evolved, or survived. “Early hominids certainly recognized that flowers were the harbingers of tasty fruits. Without flowers, perhaps no people today.”
- As costly as gold. “Saffron is the world's costliest spice and the subject of countless fake imitations,” Buchmann says. “The spice is the dried styles from crocus blooms. Hand-picking and the fact that this represents such a tiny fraction of the entire plant, make it so costly and precious.”
- For inspiration and romance. “Flowers have inspired generations of poets, writers and artists. Their myriad shapes, colors and scents enrich our lives with beauty. Their sexuality and alluring scents bring romance into our lives.”
- Most ancient. The world's earliest known flower is the 8-inch tall fossil Achaefructus that grew in China 130-160 million years ago. “It turns out that these and other early blooms were puny runts,” Buchmann says. “They wouldn't win best of show ribbons in any flower show.”
- Flowers in the service of science. “Without Gregor Mendel's crossing experiments with the humble garden pea, we wouldn't have learned about the laws of inheritance when we did. “
Buchmann has published more than 150 scientific articles and 11 popular nonfiction books, including The Forgotten Pollinators (a Los Angeles Times Book Prize finalist) with Gary Nabhan. His book, Honey Bees: Letters from the Hive, is a National Science Teachers' Association Outstanding Science Trade Book. He's also written a children's book The Bee Tree (with Diana Cohn), described as the true story of a family of honey hunters in peninsular Malaysia.
Buchmann's major professor at UC Davis was Robbin Thorp, now a distinguished emeritus professor of entomology who continues his research on native bees. Both continue to teach the annual American Museum of Natural History “The Bee Course,” along with several other colleagues.
"Steve has been on the cutting edge of many areas of pollination biology," Thorp said. "He jumps on to new ideas with great enthusiasm and explores them in depth. He has been a leader in areas like buzz pollination, the contribution of electrostatics in pollen harvesting by bees, and adaptations in bees that collect oils from specialized flowers. He raised important issues about the conservation of bees in co-authoring the benchmark book, The Forgotten Pollinators, a decade before colony collapse disorder in honey bees captured the attention of the media and general public. He enjoys new technologies and exploring ways they can be applied to pollination research. At the annual Bee Course in Arizona, he provides a very popular demonstration of life within carpenter bee nests."
Buchmann wears a number of hats. He assists documentary filmmakers as a “bee and flower wrangler,” and served as the chief scientist for the 2013 Disneynature film Wings of Life, narrated by Meryl Streep. He also produced a short film Honey for the Maya, which can be seen on YouTube.
Besides writing and his beloved buzz pollination research (funded by a National Science Foundation Grant), Buchmann enjoys macro and landscape photography, along with making small fine art bronzes in a Tucson foundry.
The former UC Davis doctoral student remembers “walking up and down the stairs to my office in the old insect museum in Briggs Hall; and chatting with botanist/evolutionist Dr. Ledyard Stebbins; studying the pollination of shooting stars (Dodecatheon) near Lake Berryessa, the area that is now the Stebbins Cold Canyon Reserve; and riding “back and forth to UC Berkeley and the UC Davis libraries on the free library shuttle.”
He did field work for his doctorate in Arizona, California, Wisconsin and Panama (Barro Colorado Island), and recalls the “wonderful mentorship of Dr. Robbin Thorp and the late Grady Webster.”
And flowers? Yes, many memories of flowers. He fondly remembers “roaming the serpentine rock outcrops of Napa Valley and inhaling the wonderful wine-like floral aroma of western spicebush (Calycanthus occidentalis) and “opening flowers of Dutchman's pipe festooning trees near Lake Berryessa, “to find their fungus gnat pollinators.”
Wild bee diversity is declining worldwide at unprecedented rates, and steps must be taken to conserve them--and not just those that are the main pollinators of agricultural crops, agreed 58 bee researchers in a study published today (June 16) in Nature Communications, an open-access journal based in London.
"This study provides important support for the role of wild bees to crop pollination through a comprehensive global summary,” said co-author and pollination ecologist Neal Williams, associate professor in the UC Davis Department of Entomology and Nematology. “At the same time, we found that in any one region, much of the pollination services from wild bees to a given crop come from just a few species, thus we need to be careful about using a simplistic economic ecosystem-services argument for biodiversity conservation and maintain actions that target biodiversity as specific goal. "
Wild bees, or non-managed bees, include bumble bees (genus Bombus), sweat bees (genus Lasioglossum) and small carpenter bees (genus Ceratina).
The study, led by David Kleijn of Wageningen University, The Netherlands, found that of the almost 80 percent of crop pollination provided solely by wild bees, only 2 percent are by the most common species. This indicates that the benefits of conserving only economically important organisms are not the same as the benefits of conserving a broad diversity of species, the researchers said.
The paper, “Delivery of Crop Pollination Services is an Insufficient Argument for Wild Pollinator Conservation,” is online at http://www.nature.com/naturecommunications. Among the co-authors are native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology at UC Davis, and conservation biologist Claire Kremen of UC Berkeley, a longtime associate of the UC Davis Department of Entomology and Nematology.
“My role in this paper was through my collaborations with Neal Williams and Claire Kremen in their research projects on crop pollination by native bees,” Thorp said. “My identifications of the bees they sampled, provided the raw data for the calculations performed on the diversity and abundances of the bees pollinating the crops they studied.”
“There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation,” the researchers wrote in their abstract. “However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops.”
“Dominant crop pollinators,” they pointed out, “persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.”
The researchers analyzed data from more than 90 studies on five continents, including Europe and North America. They concluded that the higher levels of biodiversity provide greater benefits to the functioning and stability of ecosystems, with some functions also being “economically beneficial” for humans.
Kleijn and his colleagues studied 785 species, analyzing which provide the best economic returns from crop pollination. They found that wild bee communities contribute an average of more than $3,251 per hectare (2.471 acres) to the production of crops, and that they provide the same economic contributions as managed honey bee colonies. However, they also noted that the majority of crop pollination services provided by wild bees are accomplished by only a small subset of the most common species.
“Across the 90 studies, we collected a total of 73,649 individual bees of 785 species visiting crop flowers,” the authors wrote. “Although is an impressive number, it represents only 12.6 percent of the currently known number of species occurring in the states or countries where our studies took place. When we consider only bee species that contribute 5 percent or more to the relative visitation rate of any single study, the percentage drops to 3 percent of the species in the regional species pool. Yet these 2 percent of species account for almost 80 percent of all crop visits.”
These results suggest that conservation efforts targeted directly at a few species providing the majority of ecosystem services, such as crop pollination, would represent a good strategy if the goal is to improve economic returns. However, they said such a strategy is unlikely to be compatible with conserving threatened species and biological diversity “if the goal is to improve the functioning and stability of ecosystems.”
Williams worked with Kleijn and Winfree of Rutgers University New Brunswick, N.J., to conceive of some of the approaches used, particularly suggested looking at the abundance distributions of crop bees within the larger species pools of the region to understand whether the most important crop pollinators species are simply the common bees overall.
Williams and Kremen also contributed to the manuscript, from the early drafts to the final versions.