Long-term population trends for some North American pollinators are “demonstrably downward,” says a new report from the National Research Council. However, there is little or no population data for many pollinators, which prompted the committee that wrote the report to call for stepped-up efforts to monitor these creatures and improve understanding of their basic ecology.
In order to bear fruit, three-quarters of all flowering plants—including most food crops—rely on pollinators for fertilization. Research indicates that shortages of pollinators for agriculture already exist and that decreases in wild pollinator populations could disrupt ecosystems in the future. “Despite its apparent lack of marquee appeal, a decline in pollinator populations is one form of global change that actually has credible potential to alter the shape and structure of terrestrial ecosystems,” said May R. Berenbaum, University of Illinois.
The committee concluded that the honeybee in particular is in decline. Honeybees are crucial to agriculture, pollinating more than 90 commercially grown crops; for example, it takes about 1.4 million colonies of honeybees to pollinate 550,000 acres of almond trees in California. Studies show that U.S. honeybee populations have dropped since the 1980s, when a non-native parasitic mite was introduced, although the full extent of the decline is unclear because of problems with the way the federal government collects statistics on the beekeeping industry. The U.S. Department of Agriculture’s National Agricultural Statistics Service should improve its methods for surveying honeybee populations, and do so on a yearly basis, the committee said.
Long-term trends for several wild bee species, especially bumblebees, as well as some butterflies, bats, and hummingbirds also show population drops, the committee found. However, it emphasized that a paucity of data on most wild pollinators make authoritative assessments exceedingly difficult.