University of Nevada, Reno

Research

Understanding complexity, big and small.

Our lab is interested in understanding the feedbacks between plant chemistry, trophic interactions, and landscape-level biogeochemical cycles.

 

Our projects span 3 scales:

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Plant chemistry

We study how plants allocate energy across space and time, and what it means for plant chemistry.

Insect-plant interactions

We study how plant chemistry mediates plant-animal mutualisms, particularly predators that protect plants from herbivores.

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Landscape-level processes

We study how mutualisms are engaged in feedbacks with larger-scale processes, like community assembly and carbon cycling.

Our research revolves around 3 major themes:

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Mutualisms

We explore the mechanisms underlying mutually beneficial interactions, as well as the contexts upon which they depend. Our goal is to understand how positive interactions structure communities and ecosystems.

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Scale

We explore the effects of species interactions at community and ecosystem scales, and how ecological processes, like community assembly and carbon storage, depend on scale. Our goal is to determine whether local interactions have large-scale consequences.

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Phytochemical landscapes

We explore the causes and consequences of variations in plant chemistry across the landscape. Our goal is to link plant chemistry to variation in tri-trophic mutualisms and biogeochemical cycles.

Featured projects

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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.

Check out our recent paper!
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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.

Check out our recent paper!
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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.

Our field systems

Mutualisms across the globe

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Kenya

Elephants-Ants-Acacia trees

In central Kenya, ants defend trees from the largest land mammal—the African elephant. Trees invest carbon in ants that could otherwise be used for growth or reproduction, and elephants tear down trees that don’t (or can’t) invest in this “antsurance.”

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Nevada

Milkweed-Monarch-Predator

Monarch butterflies migrate into the Great Basin from the California coast each summer. Which milkweed the monarch mother chooses for her offspring may determine larval growth rate, predation pressure, and even migratory success.

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Nevada

Alfalfa-Aphids-Nitrogen

Alfalfa plants have a belowground mutualism with nitrogen-fixing bacteria, and alfalfa aphids suck nutrients from alfalfa and use their own mutualistic bacteria to upgrade plant nitrogen into essential amino acids. Does one mutualism affect the other?

Why this work matters

Little interactions, big consequences

 

The complex interactions between plants, insects, and landscapes are often overlooked, but through our work, we’ve shown that little interactions have big consequences. By studying how mutualisms impact landscapes, we can expand discussions about biodiversity conservation and improve the accuracy of global climate models.

 
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