Songbirds and coffee farms in Central America. Ladybugs and soybean fields in the Midwest.
These are well-known, win-win stories that demonstrate how conserving natural habitat can benefit farmers.
But an international team of authors, including Megan O’Rourke, assistant professor in the Virginia Tech School of Plant and Environmental Sciences, found that natural habitat surrounding farm fields is not always an effective pest-control tool for farmers worldwide. The team’s analysis was published Aug. 2 in the journal PNAS.
“For the last 20 years, many scientists have suggested that you will have fewer insect pests on your farm if the farm is surrounded by natural habitats, such as forests,” said O’Rourke.
To test that assumption, lead authors Daniel Karp, an assistant professor in the UC Davis Department of Wildlife, Fish and Conservation Biology, and Rebecca Chaplin-Kramer, of the Natural Capital Project at Stanford University, organized an international team of ecologists, economists, and practitioners at the National Socio-Environmental Synthesis Center. Together, they compiled the largest pest-control dataset of its kind, encompassing 132 studies from more than 6,700 sites in 31 countries worldwide — from California farmlands to tropical cacao plantations and European wheat fields.
Surprisingly, the results were highly variable across the globe. While many of the studies showed surrounding natural habitat does indeed help farmers control pests, just as many showed negative effects on crop yields. The analysis indicates that there are no one-size-fits-all recommendations for growers about natural habitat and pests.
“Natural habitats support many services that can help farmers and society, such as pollination and wildlife conservation, but we want to be clear about when farmers should or should not expect the land around their farms to affect pest management,” said O’Rourke, who works within the College of Agriculture and Life Sciences and the Fralin Life Science Institute. “Diverse landscapes are not a silver bullet for pest control but should be considered as part of a holistic and sustainable pest management plan.”
Critically, Karp and his team of 153 co-authors have made their pest-control database publicly available, opening the door for further scientific insights. Karp hopes the database will grow over time and help inform predictive models about when surrounding habitat helps control pests and when it does not.
The research was supported by the National Socio-Environmental Synthesis Center and the National Science Foundation.