Graduate research from the LTER shows that prairie strips planted within agricultural monocrops are not an “ecological trap” for native pollinators – but they also don’t reduce insecticide runoff that may pose a threat.
Agriculture is essential, but the lack of biodiversity in farmland can create ecological barrens. Prairie strips – the long, thin strips of tallgrass prairie vegetation planted adjacent to agriculture – have potential to bring ecosystem services into agricultural spaces, such as increased pollination, enhanced microbial diversity, and containment of nutrient runoff.
Despite their host of benefits, there is concern that these prairie corridors may also be exposing native pollinators to harmful insecticides. Prairie strips are planted in systems that commonly utilize neonicotinoid insecticides, or “neonics.” Only a small percentage of neonics end up in the target plant tissue, but it is unknown if prairie strips accumulate neonics in concentrations lethal to insects.
In a recent collaboration between the KBS LTER and Iowa State University, former LTER graduate student Corinn Rutkoski (Michigan State University ’24) and colleagues sought to determine if prairie strips are a haven or a trap for native insects.
To test this, they collected soil samples and groundwater, and analyzed tissue from two representative plant species: the black-eyed susan and the common milkweed.
One major expectation of the study was that prairie strips would act as catchment areas to reduce the runoff of insecticides. Surprisingly, this was not the case. Prairie strips did not reduce insecticide runoff to downslope areas, as demonstrated by high neonic concentrations in soil at the base of farm fields. However, neonics were only found in two of the plant tissue samples, and at levels well below the lethal dose for insects.
This research is an important “snapshot” of the prairie strip-agricultural system, and underscores the need for longer-term assessment of neonic insecticides within prairie strips and a broader assessment of focal prairie species. Prairie strips will likely serve an important role in the future of sustainable farming, although they are not a panacea for rogue insecticides and the decline of native pollinator habitat. Prairie strip research remains a focus of the LTER, providing an ideal platform for innovative science that can answer these questions.
[This post is adapted from “Prairie strips: a refuge in an agricultural desert or an ecological trap for native pollinators?” by Mary C. Linabury, originally published on the NSF LTER website. Used with permission.]