Experiment Two
To examine bottom-up effects of the six herbicides in the absence of snail predators, we performed a follow-up experiment in 2015 using the same general experimental setup above in the same location but with a few alterations from 2011: 1) 64 mesocosm tanks were employed with 8 tanks per treatment, including the water and solvent controls, 2) five crayfish predators were randomly assigned to half of the tanks in each treatment, 3) 24 Bi . glabrata (NMRI strain) snails were placed into each tank, and 4) tanks lacked H. verticillata .