Fig. 3.

Native (Botryllus) and introduced (Botrylloides, Diplosoma) ascidians show similar growth rates at moderate temperature, but at higher temperatures the nonnative species have greater growth rates than an ecologically similar native. ANOVA results: 16.1–19.0°C: F = 0.96, P = 0.39; 19.1–21.0°C: F = 7.9, P = 0.0006; 21.1–23.3°C: F = 42.7, P < 0.0001. ANOVA was not done for 14.5–16.0°C because of poor replication for Botrylloides; unpaired t test indicated that growth of Botryllus and Diplosoma did not differ at this temperature (df = 29; P = 0.14). Different letters above each bar indicate significant differences in growth among species within that temperature range by using Tukey–Kramer post hoc tests at P < 0.05.