Bees play a considerable role in maintaining healthy ecosystems and supporting agricultural production worldwide. As pollinators, they facilitate the reproduction of numerous flowering plants, including a significant portion of the crops humans rely on for food. Growing concerns about declining bee populations prompt a closer examination of the statistical evidence.
Overview of Global Bee Population Trends
Global bee populations show varied trends, with some regions declining and others increasing. However, widespread reductions in bee species are indicated. For example, research indicates at least 30% of North American bee species have decreased over the last 50 years, and European studies suggest a loss of about 25% of bee species since the 1980s.
Despite regional declines, the worldwide number of managed bee colonies, particularly honey bee hives, has risen. The Food and Agriculture Organization (FAO) estimated approximately 102.1 million bee colonies globally in 2023, a 47% increase since 1990. This increase is largely driven by significant growth in Asia, which accounted for 45.4 million bee colonies in 2023, and Africa.
Decline Among Honey Bees
Managed honey bee populations (Apis mellifera) face distinct challenges, particularly in North America and Europe. In the United States, beekeepers report substantial overwintering losses, with annual mortality rates averaging 39.6% over a 12-year period, and some years seeing losses as high as 50.8%. Current rates significantly exceed the acceptable 21% winter loss.
Colony Collapse Disorder (CCD), characterized by the rapid disappearance of adult worker bees from a hive, leaving the queen and immature bees behind, has contributed to these losses. While CCD was associated with high colony losses (20.5% to 60%) in the U.S. between 2007 and 2014, the overall number of honey bee colonies in the U.S. has remained relatively stable or even grown since its identification. In Europe, honey bee colony losses range from 30% to 50% depending on the country.
Decline Among Wild Bee Species
Wild bee species, including bumblebees and solitary bees, are experiencing declines, often less publicized than those of honey bees. In North America and Hawaii, a comprehensive review of over 4,000 native bee species revealed that more than half of those with sufficient data are declining. Nearly one in four native bee species (347 species) are considered imperiled and at increasing risk of extinction.
Globally, up to 25% of known bee species have not been recorded in datasets since the 1990s, suggesting many have become too rare to observe. For instance, an analysis by the Xerces Society and the International Union for Conservation of Nature (IUCN) found that 28% of bumblebee species in Canada, the United States, and Mexico are classified as threatened. NatureServe reports that 50% of leafcutter bee species and 27% of mason bee species are “at risk.”
Ecological and Economic Implications of Decline
Bee population declines carry significant ecological and economic consequences. Bees and other pollinators are responsible for pollinating approximately 75% of the world’s leading food crops. This pollination contributes to the production of a wide array of fruits, vegetables, nuts, and oilseeds, important for human nutrition.
A reduction in bee populations can lead to decreased agricultural yields, potentially causing food shortages, reduced dietary diversity, and economic instability. Crops such as coffee, apples, almonds, tomatoes, and cocoa are dependent on bee pollination. If current trends continue, nutritious crops could be replaced by staple crops like rice, corn, and potatoes, leading to a less balanced diet. Beyond food production, bees maintain genetic diversity within plant populations, enhancing crop resilience to environmental pressures.