Wild bees pollinate many of the country’s most important farmlands, but a new national study suggests that these crucial pollinators are disappearing in the agricultural areas where their services are needed most.

The study, Modeling the status, trends, and impacts of wild bee abundance in the United States, was published on December 21 in the Proceedings of the National Academy of Sciences. It found that while nearly 40 percent of US croplands depend on pollinators, wild bee abundance declined by 23 percent between 2008 and 2013. This decline was generally associated with the conversion of pollinator habitat into row crop production.

This is the first national study to map U.S. wild bees. The researchers found that some of the crops most dependent on pollinators (pumpkins, watermelons, peas, peaches, plums, apples, and blueberries) are the crops most likely to run into trouble in the future. The increasing consumption of these speciality crops is mismatched with the declining pollinator populations in particular counties throughout the United States, and could lead to higher production costs for farmers and could even destabilize crop production over time.

The study identified 139 counties in the U.S. where declining bee populations directly correspond to large areas of pollinator-dependent crops. As the map below illustrates, the counties with declining bee populations on cropland and high demand for pollinator services (highlighted in pink) are highly concentrated in California’s Central Valley, the Midwest’s corn belt, and the Mississippi River valley.

The Importance of Wild Pollinators

Bees play an extremely important role in agricultural production, and in 2009 contributed to over 11 percent of the nation’s gross domestic product, equal to $14.6 billion each year. Of that, more than $3 billion was provided by wild pollinators, which depend on land where they can nest and forage.

Demand for specialty crops has increased over the past decade, but as a result of management challenges and signficant colony losses, the supply of managed honey bees has not kept up with the increased demand.

In the face of such challenges, there is evidence that wild, unmanaged bees (such a bumble bees) can provide critical pollination services where there is existing habitat to support these populations. Wild bees also improve the long-term stability of crop pollination, which can reduce the risk from variable supply or activity of managed honey bees. As a result, the study recommends that wild pollinators be integrated into crop pollination management plans in addition to, or instead of, managed bees.

Despite the clear importance of wild bees, multiple species are declining in both their geographic range and abundance. Among the multiple threats to wild bees, including pesticide application, climate change, and disease, habitat loss still contributes to the most observed population losses.

Presidential Memo Calls for Pollinator Health Promotion

In response to the declining availability of pollinator services, in 2014 the White House issued a presidential memorandum calling for a national strategy to promote pollinator health, which included the creation of a Pollinator Health Task Force. In May 2015, the task force released its National Strategy to Promote the Health of Honey Bees and Other Pollinators, which also focuses in on the serious impact of habitat loss on wild pollinator population declines.

In response, the strategy includes a goal of restoring or enhancing 7 million acres of land for pollinators over the next five year through federal actions and public-private partnerships.

Farm Bill Conservation Programs Support Critical Habitat

The U.S. Department of Agriculture (USDA) continues to address the declining pollinator populations through farm bill conservation programs, and there is still more that that can be done to encourage the creation of pollinator habitat through land retirement and working lands conservation programs.

• CRP and Pollinator Habitat

In June of last year, the USDA announced the availability of $8 million in Conservation Reserve Program (CRP) for mid-contract management incentives for Michigan, Minnesota, North Dakota, South Dakota, and Wisconsin farmers and ranchers who establish new habitats for declining honey bee populations on their existing Conservation Reserve Program (CRP) acres. These five states are home for more than half of the commercially managed honey bees during the summer and offer a large area of potential habitat.

In 2012, USDA reserved 100,000 acres of Conservation Reserve Program (CRP) land for pollinator habitat, and, to date, about 30 percent of those acres have been enrolled in the program, with a majority of enrolled acres coming into CRP during the past year. Outside of this special CRP pollinator habitat initiative, USDA estimates an additional 94,000 acres of CRP land are pollinator habitat acres.

• Working Lands Conservation Support for Pollinator Habitat

For land that was previously in the CRP but is returning to agricultural production, or for any existing working farms that wish to engage in advanced conservation systems, the Conservation Stewardship Program provides long-term stewardship payment for advanced conservation systems that can include a pollinator habitat enhancement.

To date, nearly 3,000 CSP contract holders have selected enhancements that establish pollinator habitat in non-cropped areas on their lands. Through these enhancements, participants seeded over 11,000 acres of nectar and pollen producing plants in field borders, vegetative barriers, buffer strips, and waterways, providing increased diversity for pollinator habitat.

Additionally, through the Environmental Quality Incentives Program (EQIP), USDA provided $3 million in FY 2014 and an additional $4 million in FY 2015 for technical and financial assistance for interested farmers and ranchers to improve bee health through working lands. This funding is available for conservation practices that increase habitat area and safe food sources for honey bees. We do not have acres of adoption numbers for this EQIP funding as yet.

In order to ensure the continued availability of pollinator habitat, particularly in the key areas identified in the PNAS study, USDA should continue to promote the adoption of critical activities and enhancements through its farm bill conservation programs.

The full PNAS study is available online here.