A team of researchers led by scientists at Rutgers University-New Brunswick analyzed crop yields from more than 1,500 fields on six continents and found that global production of important, nutritionally rich foods such as fruits, vegetables, nuts and legumes is limited by a lack of pollinators.
The results, detailed in Nature ecology and evolutionshowed that across crops and locations, one-third to two-thirds of farms contain fields that are not producing at the levels they should due to a lack of pollinators. The phenomenon of low crop yield due to insufficient insect visits is known as pollinator limitation.
The research is especially timely given recent concerns about global declines in insect abundance.
“Our findings are cause for concern and optimism,” said Katie Turo, study author and postdoctoral researcher in the Department of Ecology, Evolution and Natural Resources at Rutgers School of Environmental and Biological Sciences. “We have identified widespread yield shortfalls, but we also estimate that it is likely that, through continued investments in pollinator management and research, we can improve the efficiency of our existing fields to meet the nutritional needs of our global population.”
The scientists reached their conclusions by conducting a statistical analysis of more than 200,000 ‘bee visits’ to harvest flowers, recorded in one of the most comprehensive crop pollination databases in the world. Rachael Winfree, the study’s lead author and professor in the Department of Ecology, Evolution and Natural Resources, worked with several colleagues from Europe and South America to compile the most comprehensive database of crop pollination studies in the world. The open-source database contains thirty years of field observations of bees and other pollinators visiting plants.
The recent Rutgers study does not apply to important food crops, such as rice and wheat, which do not require pollinators to reproduce. But pollination by bees and other animals is critical to the spread of what Turo describes as “nutritious and interesting foods that we like and are culturally relevant,” such as fruits, vegetables, nuts and legumes.
“If you look through a list of crops and think about which fruits and vegetables you most enjoy eating — like summer berries or apples and pumpkins in the fall — those are the crops that typically need to be pollinated by insects,” Turo said.
Pollination is the process of transferring pollen from the male part of a flower to the female part, allowing a plant to be fertilized and produce seeds, fruits and young plants. Pollen can be moved by wind, water or by pollinators such as honeybees and wild bees and other insects and other animals such as bats.
Pollinators support the reproduction of about 88 percent of the world’s flowering plants and 76 percent of the world’s major food crops, according to previous research by Rutgers professor Rachael Winfree and other scientists. Bees are generally considered the most effective pollinators, as Rutgers scientists have found that blueberry, coffee and apple crops are most often affected by pollinator limitation. they visit more flowers and carry more pollen than other insects.
Researchers found yield shortfalls for 25 unique crops and in 85 percent of the countries evaluated.
On the plus side, Turo said scientists believe current yield shortfalls can be addressed with realistic increases in the number of pollinators in individual fields. The research showed that in some cases a sufficient number of bees were already visiting some fields.
If field managers could improve consistency between high- and low-yield fields, many of the observed yield problems could be addressed, she said.
“The findings are significant because crop yields, which measure the amount of crops per unit area, are relevant for assessing the adequacy of the world’s food supply relative to population,” Winfree said. “Our findings show that by paying more attention to pollinators, growers can make farmlands more productive.”
James Reilly, a data analyst in the Rutgers Department of Ecology, Evolution and Natural Resources, was also an author on the study. Other authors included Ainhoa Magrach from the Basque Center for Climate Change in Leioa, Span, and Thijs PM Fijen from Wageningen University & Research in the Netherlands.
