Featured projects
Exploring feedbacks between plant chemistry and mutualisms in a drought-stressed landscape
When plants are stressed by herbivores, they are less equipped to respond to additional threats like drought. We study drought-adapted milkweeds (Asclepias spp.) in the Great Basin desert to understand the feedbacks between plant chemistry and tri-trophic mutualisms (e.g. milkweed-monarch-predator, or milkweed-aphid-ant).
Our results suggest that herbivory can dampen plant chemical responses to water limitation. We are now investigating whether plant chemical responses to multiple stressors will dampen feedbacks between plant chemistry and trophic interactions at community scales.
Studying how a mutualism, and its breakdown, affect the carbon cycle
Most trees need animals (or microbes) to help with defense and nutrients. These service providers, called tree mutualists, are rewarded with carbon by the tree. This relationship likely has impacts on the carbon cycle, but those impacts have rarely been quantified.
By studying the mutualism between trees and defensive ants in Kenya, we can determine how much tree carbon is invested in mutualists, where that carbon comes from, and whether tree-carbon investment changes when mutualisms are disrupted by human-driven change, like the decline of large mammals (i.e. elephants) and the spread of invasive ant species.
Maximizing mutualisms to control agricultural pests
Alfalfa is a dominant cash crop in Nevada that suffers damage from numerous herbivorous pest species, including aphids. We study whether the below-ground mutualism between alfalfa and the nitrogen-fixing rhizobia bacteria affects pest densities. We are also studying whether greater plant diversity in the landscape can minimize predator dispersal and encourage the persistence of biological control through the season.
Ultimately, we are interested in how we might maximize plant mutualisms in an agricultural context, via changes in plant chemistry within the field or in the surrounding agricultural matrix.