Figure 7.

Effects of plant community composition, snail type, and predator presence on the change in (a,b) Juncus stem height and (c) Spartina stem height over the course of a 12-week mesocosm experiment. (A) When predators were present, S-snails caused a reduction in Juncus stem height in both plant communities where Juncus was present. In contrast, J-snails only caused a reduction in stem height in the mixed community. (B) When predators were absent, J-snails caused a reduction in Juncus stem height in the Juncus-only but not the mixed community. S-snails had minor effects on Juncus stem height that did not differ by plant community. (C) Changes in Spartina stem height varied by plant community composition and snail type, but they were consistent across predator treatments. Letters indicate significant differences at P < 0.05 based on Tukey’s post hoc tests. Bars represent means ± 1SE.