23
Jun
Disappearance of California Bumble Bees Calls for Urgent Protection of Pollinators Nationwide
(Beyond Pesticides, June 23, 2022) In the first California statewide bumble bee census in 40 years, a University of California—Riverside (UCR) study, published in Ecology and Evolution, reveals that once common bumble bee species in California are disappearing from the ecosystem. Wild pollinators like bumble bees provide pollination to billions of dollars worth of crops each year as these insects can flourish in cooler habitats and lower light levels than commercial honey bees. However, pollinators (such as bees, monarch butterflies, and bats) are a bellwether for environmental stress as individuals and as colonies. Both wild and commercial bees and other pollinators encounter multiple stressors, including pesticides, parasites, and poor nutrition, that act together to increase the risk of bee mortality. Therefore, studies like these highlight the need to establish monitoring and conservation frameworks incorporating varying habitats and species to assess fluctuations in biodiversity. The study notes, “Specifically, our study shows that greater monitoring of the diverse bumble bees of California is needed in order to better understand the drivers of biodiversity and decline in this genus, and to more effectively manage bumble bee conservation in the state.”
Researchers compared data on bumble bee populations in California in 1980 and 2020. After collecting bumble bees from 17 sites in Southern California with six varying ecosystems, the researchers note that they could not locate more than ten bees at each site. The researchers collected 17 types of bumble bees, representing only 68 percent of bee species that inhabit the state. The Western bumble bee is an important pollinator of wild plants and crops; however, the researchers could not find any western bumble bees. The yellow-faced bumble bee represents over half of all bees collected in the study. Although this species is the most dominant in California, the researchers find the number of suitable habitats for pollinators has decreased since the last statewide survey in 1980. The UCR entomologist Hollis Woodard, who led the study, notes, “Although we found that relative to other sites the mountains are home to the most diverse bumble bee populations, even at those sites we also failed to find some species that used to be there.”
Seventy-five percent of the 115 top global food crops depend on insect pollination, with one-third of all U.S. crops depending on pollinators. However, research finds that many insect populations are declining primarily from habitat fragmentation, climate change, and extensive pesticide use. Pesticides are of great concern as these toxic chemicals are everpresent in the environment, and many are toxic to bees, including neonicotinoids, sulfoxaflor, pyrethroids, fipronil, and organophosphates. Pesticides intensify pollinators’ vulnerability to health risks (such as pathogens and parasites) with pesticide-contaminated conditions limiting colony productivity, growth, and survival. Research shows that residues from neonicotinoids (including seed treatments) and sulfoxaflor accumulate and translocate to pollen and nectar of treated plants, increasing the potential risk to pollinators. Moreover, systemic neonicotinoid insecticides put 89 percent or more of U.S. endangered species at risk. Both pyrethroids and fipronil impair bee learning, development, and behavioral function, reducing survivability and colony fitness. However, inert ingredients in these products cause similar or more severe impacts on bee populations, such as disruption in bee learning behavior through exposure to low doses of surfactants. With the global reliance on pollinator-dependent crops increasing over the past decades, a lack of pollinators threatens food security and stability for current and future generations.
This study is the first to provide a broad overview of California bumble bee populations in nearly 40 years, demonstrating a decrease in wild bumble bee diversity and abundance. Pollinators across the globe are in danger from multiple interacting stressors, from climate change to pesticide use, disease, habitat destruction, and other factors. As plants die off or adapt to fewer pollinators, pollinators play less of a role, finding less food and resulting in further stress. In the U.S., an increasing number of pollinators, including the American bumblebee and monarch butterfly, are being added or considered for listing under the Endangered Species Act. Most recently, the Sacramento-based California Court of Appeal ruled bumblebees and other invertebrates eligible for protection as endangered or threatened “fish” under the California Endangered Species Act (CESA) after being left out of CESA protection for decades. Therefore, adequate legislation protecting species’ health can alleviate harmful effects on farmed and natural environments. The study concludes, “Key barriers to successfully implementing species-specific conservation actions include the lack of large-scale monitoring studies to identify general patterns, as well as knowledge gaps in life history and drivers of species decline. Overcoming these barriers and protecting important species, like bumble bees, is necessary to prevent cascading negative impacts on agricultural and natural ecosystems.”
Wild and managed pollinators provide many ecosystem services that contribute to the well-being of all plant and animal species globally. Thus, for Pollinator Week 2022, Beyond Pesticides suggests actions to create pollinator habitat, go organic with your community, and urge comprehensive action at the federal level to protect declining populations. With the crisis continuing, we must redouble these efforts. Concerned residents and pollinator advocates are encouraged to take these steps not only in and around their properties but at their place of work and in their community in local parks and natural areas. Ending toxic pesticide use can alleviate the harmful impacts of these chemicals on species and ecosystem health. Commit to taking meaningful action to protect pollinators, the plants, people, and entire ecosystems that rely upon them.
Learn more about the science and resources behind pesticides’ impact on pollinators, including bee pollinator decline, and take action against the use of pesticides. Additionally, find more about what you can do to protect bees and other pollinators by checking out information on the BEE Protective Campaign, pollinator-friendly landscapes, pollinator-friendly seeds, pesticide-free zones, bee-friendly habitats, and what you, or your state representative, can do to protect our pollinators. For more information on the insect apocalypse, see the Beyond Pesticides article in our Pesticides and You newsletter, Tracking Biodiversity: Study Cites Insect Extinction and Ecological Collapse.
Furthermore, buying, growing, and supporting organic agriculture can help eliminate the extensive use of pesticides in the environment. Organic land management eliminates the need for toxic agricultural pesticides. For more information on the benefits of organic, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
All unattributed positions and opinions in this piece are those of Beyond Pesticides
Source: Science Daily, Ecology and Evolution
