Anthropogenic air pollutants reduce insect-mediated pollination services

Area of Science:

• Environmental Science
• Ecology
• Atmospheric Chemistry

Background:

• Air pollutants, including nitrogen oxides (NOx) from diesel exhaust and ozone (O3), are suspected of contributing to pollinator decline.
• Laboratory studies suggest pollutants can alter floral scents, disrupting insect foraging cues.

Purpose of the Study:

• To investigate the in-situ effects of air pollutants on pollinator foraging and pollination services.
• To assess the impact of realistic pollution levels on insect-pollinator interactions and ecosystem services.

Main Methods:

• Utilized free-air fumigation to expose local ecosystems to elevated levels of diesel exhaust and ozone, both individually and in combination.
• Monitored counts of wild and managed insect pollinators, their flower visits, and pollination/yield metrics of a self-fertile test plant.

Main Results:

• Pollutant exposure, at levels below current safety standards, significantly reduced pollinator counts (62-70%) and flower visits (83-90%).
• Reductions were observed across various pollinator groups, including bees, flies, moths, and butterflies.
• Pollination and plant yield metrics decreased by 14-31% in response to the simulated pollution levels.

Conclusions:

• Air pollution, even at sub-standard levels, demonstrably disrupts pollinator behavior and diminishes crucial pollination ecosystem services.
• Findings highlight the significant ecological consequences of air quality on natural systems and human reliance on them.