In animal husbandry, the macrocyclic lactone anthelmintic moxidectin is commonly used and may accumulate in pasture soils, potentially impacting plant growth and fitness. To investigate these effects while considering plant competition, we conducted a completely randomised pot experiment. We grew four temperate grassland species - Achillea ptarmica, Agrostis capillaris, Dianthus deltoides, and Plantago lanceolata - separately in pots, with soil treated with formulated moxidectin at three concentration levels (0.1, 1, 5 μg g