Intense Disturbance Enhances Plant Susceptibility to Herbivory: Natural and Experimental Evidence

Abstract

Following Hurricane Lili, which passed directly over the site of our ongoing study in Great Exuma, Bahamas, herbivory increased on devastated islands exposed to the storm surge, but not on protected islands. Observations suggested that foliage sprouting on severely damaged shrubs was more susceptible to herbivores than was new foliage on undamaged shrubs. To test this hypothesis, we conducted a controlled field experiment: hurricane damage was simulated by pruning shrubs on replicated islands. Seven months after the manipulation, herbivory was 68% higher on pruned shrubs than on controls. Leaf size and percentage of nitrogen were higher, and leaf toughness and trichome density were lower on pruned shrubs than on controls. The experimental results indicate that enhanced herbivory on exposed islands following Hurricane Lili was caused, at least in part, by increased susceptibility of the sprouted foliage to herbivorous arthropods. Because sprouting occurs on many woody plants following natural or anthropogenic disturbances, the findings in this study may have broad implications. Corresponding Editor: S. C. Pennings.