Are scared prey as good as dead?

Predators affect prey and their resources by changing the density and traits (e.g. morphology and behavior) of those prey. Ecological studies and models of community dynamics, however, typically only incorporate how changes in prey densities, rather than their traits, affect community dynamics. In a recent meta-analysis, Preisser et al. show that trait effects are as large, if not larger than density effects. This strongly suggests that trait effects should be integrated into empirical and theoretical studies.