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California’s almond trees rely on honey bees and wild pollinators, but a lack of good habitat is making their job harder

(Pictured above: A bee pollinates a flower on an almond tree in Dixon, California, on Thursday, March 4, 2021. Credit: David Paul Morris/Bloomberg via Getty Images)

This story appeared in Inside Climate News on June 3, 2021

By Anne Marshall-Chalmers (’22)

In late winter, David Bradshaw walks the rows of blossoming almond trees in California’s San Joaquin Valley listening to the hum of his honey bees at work. Some swoop to the base of the flower aiming for nectar, others zip about, wearing pollen like pants.

In the late 1950s, when his dad started Bradshaw Honey Farms in central California, honey turned a profit. Now the business survives on pollination: About1.6 million colonies of commercial honey bees are placed in almond orchards in California—the state grows 80 percent of the world’s almonds—to pollinate trees from January to March, with many bees trucked in from out-of-state.

The demand for pollinator-dependent crops like almonds, blueberries and apples, has grown 300 percent globally in the past 50 years, according to arecent study in Environmental Science & Technology. But the authors of the report,  from the University of Pittsburgh and Penn State, found that the areas of the United States most reliant on insect pollinators for high-value crops also tended to have poor habitat for pollinators, with regular use of pesticides and a lack of plentiful, diverse flowering plants.

Bradshaw can shuttle his honey bees 100 miles into the Sierra Nevada Mountains for a wide range of natural vegetation after months spent in nut and fruit trees. But wild bees don’t have that luxury, and they are suffering. “Where we have intensive production, like in much of the Central Valley, the number of bees and diversity of species is lower,” said Neal Williams, a professor of bee biology at the University of California, Davis. California’s current drought is only adding to the strain on the bees.

Little is known about how much wild pollinators—bumble bees, squash bees, mason bees­—contribute to the pollination and production of food. But Christina Grozinger, director of the Center for Pollination Research at Penn State, said there’s growingevidence that the presence of wild pollinators compliments and improves the work of honey bees. “Many studies have shown that if you have multiple species of bees, then you get better pollination,” she said. “Having a diverse community of pollinators can be crucial for both production and quality.”

Wild bees are specialists, faithful to certain plants, unlike honey bees that pollinate a whole host of crops. Take the alfalfa leafcutting bee: While honey bees chew alfalfa flowers to try and steal nectar, avoiding the plant’s reflex to smack visiting pollinators with a pollen ball, the alfalfa leafcutting bee doesn’t mind taking the hit and carrying off the pollen.

Williams said that in California, when wild mining bees emerge in the spring and fly into almond and fruit orchards, there’s an increase in nut and fruit yield. And a diversity of pollinators often creates a more marketable crop, he said, adding that growers “want to minimize risk, they want something consistent year to year.”

For a long time, the services of wild pollinators were considered to be free and abundant, and therefore taken for granted. “Things that don’t get valued get deteriorated,” said Vikas Khanna, an associate professor of civil and environmental engineering at Pitt’s Swanson School of Engineering. In addition to habitat loss, exposure to fungicides andneonicotinoids—a systemic insecticide used to kill off a number of agricultural pests—is causing great harm to pollinators, both wild and commercial. It also has been cited as one cause of Colony Collapse Disorder (CCD), in which the majority of worker bees in a honey bee colony disappears, leaving behind a queen and few nurse bees to care for immature bees.

In a recentstudy, researchers found that since 2006, when CCD struck the United States, commercial beekeepers have kept up with the loss by raising the cost of their services and replacing lost colonies. “Prices went up quickly as needed,” said Kathy Baylis, an economist and professor of geography at University of California, Santa Barbara and a co-author of the study.

During almond pollination season, as many as 230,000 colonies collapse in California, according toUSDA surveys. Pollination fees are now the largest single component of operation costs in almond production in the Sacramento and northern San Joaquin valleys. (Farther south, irrigation expenses eclipse pollination.)

Erik Lichtenberg, a professor at the University of Maryland’s Department of Agricultural and Resource Economics, said high costs alone should encourage economists and ecologists to partner and better understand the value of maintaining robust wild pollinator populations. “These should be hard-headed business decisions, not pie-in-the-sky, I love the environment,” he said.

Some almond growers are beginning to experiment with diversifying pollinators. The blue orchard bee is a metallic blue bee that’s native to California. The bees collect dry pollen on their bellies and scatter it from flower to flower more efficiently than honey bees, which pack pollen into tight balls with spit. And unlike honey bees, which stick within one tree or row of trees, blue orchard bees fly erratically, perfect for almonds that require cross pollination among varieties.

While blue orchard bees brought in by growers are raised for commercial use and are not wild, Grozinger is hopeful that as species other than honey bees are deemed valuable, action will follow, like a shift towards agricultural land with an abundance of native, flowering plants that will lure pollinators and predator bugs that control pests. Grozinger likens this to an “ecological intensification” of land, or a more natural way to keep the agricultural landscape in balance, rather than turning to chemicals.

“You can have more of these ecosystem services supported by wild systems.” Such a different approach  wouldn’t be an easy pivot for large farms, but Licthenburg says it’s time to reassess benefits and risks in agriculture.

“Environmental economics has evolved,” he said. “Just because we don’t pay for something doesn’t mean it doesn’t have value. The stuff nature provides, it’s important to understand those services can be incredibly valuable. And it’s important to think about their value, and the tradeoffs. If we cultivate more land, well, what would we lose?”

Healthy pollinator habitat, Williams says, would include a variety of blooming flowers, as well as open spaces where wild bees could burrow and nest without the threat of tillage, herbicides and pesticides. Bradshaw, who grew up in the San Joaquin Valley, recalls a time when dirt along roads or canals bustled with activity. “As a youngster, I remember you’d go up to a (dirt) bank, there were all kinds of (wild bees) digging tunnels and flying in and out,” he recalled.

This year is likely to prove exceptionally challenging to wild and managed pollinators. Research has shown even slight increases in temperature can have an impact on nectar yield and therefore bee health. Williams said the lack of rainfall in a drought year will greatly decrease vegetation.”Flowers that once flowered in July,” he said, “they’re flowering now and finishing now. Plants are moving through their growth season quickly and drying out.”

Bradshaw said parts of the San Joaquin Valley are so dry that weeds aren’t even bothering to surface. He was recently talking to a fellow beekeeper who was wondering if Bradshaw was going to transport his bees to the Sierra foothills to feast on native blue curl. “I said, ‘No. I’m not going there because my bees would starve to death,’” Bradshaw said. “We’re in deep trouble. Because of the drought, where there’s typical forage, there’s nothing. It’s like scorched earth.”


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Anne Marshall Chalmers ( 2022 )

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