Simulated Herbicide Drift Effects on Seed Germination, Seedling Emergence, and Seedling Growth of Native Plants of the Northern Great Plains.

Small concentrations of herbicide, such as those found in drift, can affect nontarget plants at different life-history stages including seed germination and seedling emergence as well as seedling growth. Fragmented landscapes, such as those in the northern Great Plains, lead to increased proximity of ecological restoration sites to agricultural lands using herbicides. Germination, emergence, and growth are crucial life-history stages leading to ecological restoration success, but these stages are sensitive to impacts from external factors such as herbicide exposure. A lab germination experiment and a greenhouse emergence experiment were performed to examine the effect of herbicides (2,4-dichlorophenoxyacetic acid [2,4-D], atrazine, and trifluralin) on species used in ecological restorations in the northern Great Plains. Seed germination, seedling emergence, and seedling growth of many study species decreased with exposure to herbicides at different concentrations representative of herbicide drift. At concentrations as low as 0.1% recommended application rate 2,4-D elicited broad effects on final seed germination percentage and germination rate. Atrazine affected seedling emergence and growth for a number of study species at concentrations as low as 10% recommended application rate. Trifluralin affected germination, emergence, and growth of the fewest number of study species. The information gained from these experiments can be used to inform restoration practitioners of best practices and recommended species to use when implementing ecological restoration adjacent to agricultural lands. Environ Toxicol Chem 2024;00:1-11. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.