Impacts of nonnative species. Managers thought a lower proportion of nonnative species were likely to degrade ecosystem services for humans (c Fisher’s Exact Test, P < 0.05) compared to other ecological or aesthetic impacts (a, b, d), and nonnative species impacts on native species populations or ecosystem processes were more likely to be cited as justification for managing them (e Fisher Exact Test, P < 0.001). Error bars represent 95% confidence intervals.