XVI International Botanical Congess

Here we show that uncertainty applies not just in physics, but also in ecology. We tested whether measuring herbivory influenced the effects of herbivory for 8 species in an old-field. Half of the plants were touched weekly to simulate the handling necessary to take morphological measures, and the other 1/2 left undisturbed. After 8 weeks, 4 of 8 species showed a significant difference in mortality or leaf area damaged as a function of visitation. Handling affected three species positively and one negatively. This surprising result serves as a reminder that seemingly benign methods may have dramatic effects on experimental results. Since the effects of handling differs among species, field researchers must integrate this new form of uncertainty into their experimental designs.