World-wide, pollinator populations are shrinking and several factors are contributing to this disturbing global trend.

How do we know pollinator populations are in decline?
Historically, managed honey bee populations in the US and Europe have been monitored due to their vital role in providing pollination services in agricultural systems. Several studies indicate that American and European beekeepers are suffering large annual losses. In the US, beekeepers have lost ~30% of their colonies every year since 2006, with total annual losses sometimes reaching as high as 42% (Bee Informed Partnership). Population changes in other insect pollinator species, such as other bee species, flies, butterflies and beetles have not been as closely tracked. Indeed, there are several hundred thousand species of pollinators and tracking all of them is not possible. However, surveys have documented disturbing population declines and even local extinctions of select pollinator species across Europe and the US.

Why are pollinator populations in decline?
Wild and managed pollinators face numerous stressors. Honey bees, other managed pollinator species such as bumble bees and orchard bees, and wild bees suffer from exposure to parasites and pesticides, and loss of floral abundance and diversity due to increased land-use. In addition, habitat destruction limits nesting sites for wild pollinators. Unfortunately, these stressors may interact synergistically to produce more detrimental effects on pollinator health.

Read more about biotic and abiotic stressors and the health hazards they pose for pollinators.