06
Aug
Wild Pollinator Declines Result in a Loss of U.S. Crop Production
(Beyond Pesticides, August 6, 2020) New research finds that a decline in wild pollinator abundance, notably wild bees, limits crop yields in the U.S., according to the study, “Crop Production in the USA Is Frequently Limited by A Lack of Pollinators.” The study results, published in the journal Proceedings of the Royal Society B, find the annual, national average value of wild bee pollination for the most economically important and pollinator-dependent crops is approximately $1.5 billion, with the total value of all U.S. pollinator-dependent crops equaling $50 billion annually.
The United Nations states that 75% of the 115 top global food crops depend on insect pollination, with one third of all U.S. crops dependent on pollinators, according to the U.S. Department of Agriculture (USDA). However, research finds that many insect populations are declining by half with a third threatened by extinction, including managed and wild pollinators, mainly due to habitat fragmentation, climate change, and extensive pesticide use. With the global reliance on pollinator-dependent crops increasing over the past decades, a lack of pollinators threatens food security and stability. The researchers in the study note, “Our findings show that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to [the] pollination of most study crops in major crop-producing regions.”
A majority of global crops rely on pollinators like insects and animals for fertilization, so reports of “biological annihilation” and a 6th mass extinction among mammals, vertebrates, and invertebrate species are concerning for crop production. However, the extent to which pollinators limit crop production and the role of wild pollinators (as opposed to managed) are relatively unknown, especially in chemical-intensive farming. This study adds to the growing body of research supporting pollinators’ economic, social, and environmental global importance, especially for the future of the agricultural industry.
This study aimed to answer the following questions: how ubiquitous is pollination limitation; what contributions do wild bees and honey bees make to crop yields/production; what is the economic value of the contributions? To do this, researchers examined the results of a nationwide empirical study using 131 commercially managed pastures throughout the U.S. and parts of Canada containing the seven most economically valuable, pollinator-dependent crops. These crops include highbush blueberry (Vaccinium corymbosum), apple (Malus pumila), sweet cherry (Prunus avium), tart cherry (Prunus cerasus), almond (Prunus dulcis), watermelon (Citrullus lanatus) and pumpkin (Cucurbita pepo). Researchers collected data related to pollinator visitation rates, pollinator type (wild or managed), and crop production/yield upon observation of the seven crops. To estimate the frequency of pollinator limitation for each crop, researchers employed an Akaike information criterion (AIC)model. Lastly, researchers determined the economic value given to each crop via pollination using the equation Vpollinator=Vcrop⋅D⋅Ppollinator.
This multi-region study finds that wild bees pollinate crops at a similar rate or higher than managed honey bees, even in regions where agricultural practices are chemical-intensive. Out of the seven crops, pollinator limitation impacts five, including apples, blueberries, sweet cherries, tart cherries, and watermelon. Additionally, wild bees deposit more pollen per flower than honey bees for six out of the seven crops, including apples, blueberries, sweet cherries, tart cherries, watermelon, and pumpkin. The nationwide estimate for the annual production value of wild pollinator is over $1.5 billion, with the value of honey bees amounting to $6.4 billion. However, a majority of honey bees’ economic value comes from pollinating almonds, which have one of the highest national values, due to the immense use of managed honey bees (over 2 million hives) required to maintain yield and production.
The agricultural industry relies on insect pollinators to facilitate fertilization and maintain annual crop yield. Globally, the production of crops dependent on pollinators is worth between $253 and $577 billion yearly. While many commercially managed fields have honey bee colonies on-site, and farmers often rely on this single pollinator species for crop pollination, there is a growing body of research finding that wild pollinators can contribute just as much to managed fields, even with the use of agrochemicals. However, the decline of pollinators like commercially managed honey bees, wild bee species, butterflies, and more, is a cause of concern, especially for future food production and security. Additionally, the reliance on pollinator-dependent crops coupled with the use of single species pollination can work synergistically to increase the risk of food insecurity.
One of the main factors contributing to pollinator population and health decline is the extensive use of chemical pesticides. Over the last decade and a half, increasing scientific evidence shows a clear connection between the role of pesticides in the decline of honey bees and wild pollinators (i.e., wild bees, butterflies, beetles, birds, bats, etc.), alike. There are various bee-toxic pesticides with the main classes of pesticides including, neonicotinoids, sulfoxaflor, pyrethroids, fipronil, and organophosphates. Research shows that residues from neonicotinoids (including seed treatments) and sulfoxaflor accumulate and translocate to pollen and nectar of treated plants, thus increasing the potential risk to pollinators. Both pyrethroids and fipronil impair bee learning, development, and behavioral function, reducing survivability and colony fitness. Organophosphates, mainly employed in mosquito control, are highly toxic to bee and other non-target organisms, causing bee deaths upon exposure to pesticide residues on plant surfaces. Moreover, the sublethal effect of exposure to these pesticides can increase bees’ vulnerability to parasites and pathogens. Realistic levels of exposure to neonicotinoid insecticides impair honey bees’ ability to groom mites off of their bodies, thus increasing the risk of the infectious disease known as deformed wing virus (DWV). Research also finds that low levels of exposure from pesticides make honey bees more susceptible to gut parasites like Nosema ceranae. Although the direct impact pesticides have on pollinators is of great concern, the indirect impacts of pesticides on pollinator habitats are equally troublesome. Pesticide use on mono-crop agriculture and genetically engineered crops can drift onto and destroy adjacent milkweed habitats that monarch butterflies rely on for lodging and reproduction.
Overall, a decline in pollinators has a direct effect on the environment, society, and the economy. Without pollinators, many plant species, both agricultural and nonagricultural, will decline or cease to exist. In turn, the market will falter, as much of the economy (65%) is dependent upon agricultural revenue. With no pollinators to help maintain yields, the economic value of the crop is depressed. However, research finds that organic agriculture boosts local economies as green spaces, like community gardens, will expand viable habitat for pollinators and food sources for people. Low-maintenance gardening and reduced pesticide use can aid in turning gardens organic, and many plants considered weeds (i.e., dandelions, creeping buttercups) are critical for pollinator survival, especially in urban areas where vegetation is sparser.
The debate of relative importance of managed, costly honey bees in comparison to gratis wild bees for pollination is a long-standing conflict. However, this research reconciles the conflicting evidence among wild and managed bees with the finding that wild bees are a more substantial contributor to pollination than honey bees. Although researchers hypothesized wild bees might not fare well pollinating crops in commercially managed fields due to the use of agrochemicals, wild bees remained persistent and making considerable but variable contributions to crop pollination. Furthermore, new evidence of pollinator limitation allows for useful comparison between other previous analyses as researchers studied large commercial farms representative of the majority of U.S. crop production.
Since the threat to pollinator health is widespread, the study researchers advise farmers to adopt practices that conserve and or bolster wild bee populations, like planting wildflowers or using alternative managed pollinators to increase crop yields. Because wild bees are economically important, it underscores the importance of economic investments in pollinator conservation efforts. The study concludes that agricultural industry investments in pesticides and fertilizers would be detrimental without confronting the decline of wild pollinators first. After all, these chemicals lack any real monetary benefits for farmers. While the study suggests, “increasing investment in honeybee colonies” as an “alternative approach to reducing pollinator limitation,” using a single species for crop pollination can have detrimental impacts on species due to genetic uniformity and disease specialty. Additionally, with the Trump Administration approving the use of the bee-toxic pesticide sulfoxaflor in 2019, all bee health remains of concern, especially as the USDA stopped collecting data for the agency’s Honey Bee Colony Survey. Beyond Pesticides states, “Permitting its use and then ceasing to collect and report data on the status of honey bees that are likely to be impacted is not only a recipe for kneecapping the study of bee decline and imperiling the food supply, but also another example of the corruption for which this administration is infamous.”
Pollinator protection policies need improvements, not only to safeguard wild pollinators but the crops they pollinate as well. Beyond Pesticides holds the position that we must move beyond pesticide reduction and commit to complete pesticide elimination in our agricultural system to prevent crop loss presented in this study. Pesticide elimination can alleviate the effect these toxic chemicals have on humans and wildlife. With EPA failing to take the most basic steps to protect declining pollinators, it is up to concerned residents to engage in state and community action and demand change. Moreover, the government should pass policies that eliminate a broad range of pesticides by promoting organic land care.
Learn more about the science and resources behind pesticides’ pollinator impact and take action against the use of pesticides. To find out more about what you can do to protect wild bee and other pollinators, check out information on pollinator-friendly landscapes, and pollinator-friendly seeds, and organic agriculture. Buying, growing, and supporting organic can help eliminate the extensive use of pesticides in the environment. Organic land management eliminates the need for toxic agricultural pesticides. Furthermore, regenerative organic agriculture nurtures soil health through organic carbon sequestration, while preventing pests and generating a higher return than chemical-intensive agriculture. For more information on how organic is the right choice for both consumers and the farmers and farmworkers who grow our food, see Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
