Expert Report

Each report is produced by a committee of experts selected by the Academy to address a particular statement of task and is subject to a rigorous, independent peer review; while the reports represent views of the committee, they also are endorsed by the Academy. Learn more on our expert consensus reports.

Pollinators--insects, birds, bats, and other animals that carry pollen from the male to the female parts of flowers for plant reproduction--are an essential part of natural and agricultural ecosystems throughout North America. For example, most fruit, vegetable, and seed crops and some crops that provide fiber, drugs, and fuel depend on animals for pollination. This report provides evidence for the decline of some pollinator species in North America, including America\u0092s most important managed pollinator, the honey bee, as well as some butterflies, bats, and hummingbirds. For most managed and wild pollinator species, however, population trends have not been assessed because populations have not been monitored over time. In addition, for wild species with demonstrated declines, it is often difficult to determine the causes or consequences of their decline. This report outlines priorities for research and monitoring that are needed to improve information on the status of pollinators and establishes a framework for conservation and restoration of pollinator species and communities.

Key Messages

  • As noted, improved information gathering for the beekeeping industry is critical, and the NASS should modify its data collection methodologies. In addition, the potential for the development of new management protocols to increase the use of wild pollinator species for agriculture should be explored to create alternatives to honey bees as commercial pollinator demands rise and shortages become likely.
  • Effective conservation or restoration of pollinator populations requires comprehensive knowledge of their biology, which is currently insufficient to inform the design of sustainable management and maintenance programs.
  • Introduced parasites and pathogens clearly have harmed some managed pollinators, most notably honey bees.
  • Long-term population trends for the honey bee, the most important managed pollinator, are demonstrably downward. Similar data are not available for other managed pollinators, such as alfalfa leafcutting bees and bumble bees.
  • Long-term, systematic monitoring is necessary for unambiguous documentation of trends in species abundance and richness. Such monitoring allows detection of relationships between changes in pollinator communities and the putative causes of change.
  • Managed pollinator decline and rising cost of pest control could increase pollinator rental fees.
  • Research in genetics and genomics has facilitated the development and maintenance of mite- and pathogen-resistant stocks of honey bees. However, these technologies have not been widely adopted, and there is a pressing need for translational research to synthesize commercially viable practices from the results of basic research.
  • The causes of decline among wild pollinators vary by species but are generally difficult to assign definitively. Pathogens that have spilled over from commercially produced bumble bees for greenhouse pollination appear to have contributed to declines in some native bumble bees. Other factors for which there is convincing evidence include habitat degradation and loss, particularly for some bats, bees, and butterflies.
  • The consequences of pollinator decline in nonagricultural systems are more difficult to define, but one important result could be an increased vulnerability of some plant species to extinction.