Epibiota of native hosts disperse with increased temperature (iv)
Finally, our results support the hypothesis that dispersion among native epibiota increases at elevated temperature. In addition to a general effect of temperature (Figure 3N, S), within-population dispersion at 22 °C was indeed substantially higher in native populations compared to non-native populations (Figure 3O, T). In contrast, at 15 °C dispersion was similar between the ranges. Therefore, our results show that under thermal stress, stochastic processes contributed relatively more to epibiota in natives than in non-natives and this corroborates that microbial communities associated with non-native hosts were more stable than those associated with native hosts. We note again that the algae from non-native populations were cooled before transport and this could potentially have resulted in a slightly stronger disturbance compared to the treatment that native algae received. However, at t0(after cooling and transport, before the antibiotic treatment) beta diversity did not differ between native and non-native populations, which indicates that the observed differences in dispersion developed after the application of the treatment.