PARENT SESSION
Oral Session #78: Herbivory: Effects on Plants.
Presiding: C. Ivey
Thursday, August 8. 9:00 AM to 11:30 AM. Apache Meeting Room, TCC.

A habitat-dependent mutualism - or where-o-where did all the gilia go?

Paige, Ken^*,1, ¹ University of Illinois, Urbana/Champaign, IL

ABSTRACT- Species interactions are often dependent upon the context in which they occur yet, studies describing the range of outcomes in any one interaction are relatively few. In this study I show that the outcome of interactions between the monocarpic biennial scarlet gilia, Ipomopsis aggregata, and its ungulate herbivores, mule deer, Odocoileus hemionus and elk, Cervus elaphus, is dependent upon the habitat in which the interaction takes place. Interactions range from mutualistic in which herbivory can lead to a 2-fold increase in plant fitness to antagonistic in which herbivory can lead to a 1700-fold decrease in fitness. These observations explain why scarlet gilia are not found in nutrient rich, moist montane meadows where they should be the most productive.

KEY WORDS: herbivory, mutualism, scarlet gilia, habitat-dependence