Phytochemical diversity and intraspecific variation maintain species diversity:
Phytochemical diversity is a metric that encompasses the richness and relative abundance of small, specialized metabolites, which can be measured as individual compounds (compositional diversity), structural complexity of compounds, or overall metabolic complexity (including both composition and structure). These dimensions of chemical diversity can vary among related species, within a plant species across the landscape, or within an individual over ontogeny and across changing environmental conditions. Our group has developed complementary 1H-NMR and LC-MS techniques and statistical analyses to quantify the multiple dimensions of chemical diversity, validated through controlled chemical experiments to support interpretation in natural systems. Our findings demonstrate that we can quantify and compare meaningful measures of chemical diversity between and within species, and answer previously unattainable questions.
Phytochemical diversity is a metric that encompasses the richness and relative abundance of small, specialized metabolites, which can be measured as individual compounds (compositional diversity), structural complexity of compounds, or overall metabolic complexity (including both composition and structure). These dimensions of chemical diversity can vary among related species, within a plant species across the landscape, or within an individual over ontogeny and across changing environmental conditions. Our group has developed complementary 1H-NMR and LC-MS techniques and statistical analyses to quantify the multiple dimensions of chemical diversity, validated through controlled chemical experiments to support interpretation in natural systems. Our findings demonstrate that we can quantify and compare meaningful measures of chemical diversity between and within species, and answer previously unattainable questions.
Synergistic effects of plant defensive chemistry:
Plants produce diverse mixtures of specialized metabolites to minimize biomass loss to herbivores. These complex chemical profiles are challenging for herbivores to adapt to and often exhibit synergistic effects. Synergy occurs when the combined effects of phytochemical mixtures exceed sum of individual compound effects. Interestingly, many isolated or synthesized plant specialized metabolites lose their presumed function in biological assays, spurring influential hypotheses on phytochemical diversity's ecology and evolution. Through collaborations that integrate organic synthesis, isolation, chemical ecology, bioassays, and quantitative analyses, our lab has investigated synergistic effects across various systems. We have found that generalist herbivores fared worse on mixed compound diets compared to single diets, while specialists performed better on mixtures.
Plants produce diverse mixtures of specialized metabolites to minimize biomass loss to herbivores. These complex chemical profiles are challenging for herbivores to adapt to and often exhibit synergistic effects. Synergy occurs when the combined effects of phytochemical mixtures exceed sum of individual compound effects. Interestingly, many isolated or synthesized plant specialized metabolites lose their presumed function in biological assays, spurring influential hypotheses on phytochemical diversity's ecology and evolution. Through collaborations that integrate organic synthesis, isolation, chemical ecology, bioassays, and quantitative analyses, our lab has investigated synergistic effects across various systems. We have found that generalist herbivores fared worse on mixed compound diets compared to single diets, while specialists performed better on mixtures.
Diet specialization in woodrats:
Divergence in ecologically adaptive traits may be maintained across small spatial scales, even with ongoing geneflow between closely related species. My lab is working to understand the role diet specialization and detoxification in maintaining species separation of two species of woodrat across a sharp ecotone. We used DNA metabarcoding coupled with chemical analysis of woodrat fecal samples to investigate differences in dietary ecology, gut microbiome, and metabolome in two closely related species and their hybrids: Neotoma bryanti (Bryant’s woodrats) and Neotoma lepida (Desert woodrat). We found that, Frangula californica (California coffeeberry) made up ~30-40% of the diet of N. bryanti, while Prunus fasciculata (desert almond) contributed ~60-65% of the diet of N. lepida . My lab is currently investigating how the chemistry of these two primary food plants is detoxified in woodrats by chemically analyzing urine, feces, and blood samples from a fully crossed feeding trial. By combining microsome assays with our metabolomic approaches, we are quantifying the role of liver enzymes (cytochrome P450s) in detoxifying these plants' toxins.
Divergence in ecologically adaptive traits may be maintained across small spatial scales, even with ongoing geneflow between closely related species. My lab is working to understand the role diet specialization and detoxification in maintaining species separation of two species of woodrat across a sharp ecotone. We used DNA metabarcoding coupled with chemical analysis of woodrat fecal samples to investigate differences in dietary ecology, gut microbiome, and metabolome in two closely related species and their hybrids: Neotoma bryanti (Bryant’s woodrats) and Neotoma lepida (Desert woodrat). We found that, Frangula californica (California coffeeberry) made up ~30-40% of the diet of N. bryanti, while Prunus fasciculata (desert almond) contributed ~60-65% of the diet of N. lepida . My lab is currently investigating how the chemistry of these two primary food plants is detoxified in woodrats by chemically analyzing urine, feces, and blood samples from a fully crossed feeding trial. By combining microsome assays with our metabolomic approaches, we are quantifying the role of liver enzymes (cytochrome P450s) in detoxifying these plants' toxins.
Eco Metabolomics:
In the pursuit of understanding chemically-mediated interactions, we are often faced with the challenge of deciphering the ecologically and biologically important compounds from diverse phytochemical mixtures. We overcome these challenges through solid chemistry collaborations and using context specific statistical workflows.
In the pursuit of understanding chemically-mediated interactions, we are often faced with the challenge of deciphering the ecologically and biologically important compounds from diverse phytochemical mixtures. We overcome these challenges through solid chemistry collaborations and using context specific statistical workflows.
Fire Ecology:
Understanding the impacts of disturbance in altering diversity and multitrophic interactions has been a cornerstone of ecological research for decades. My early research as a graduate student quantified the effects of treefall gaps on bottom-up and top-down interactions in a lowland tropical forest. This research focus on disturbance is ongoing and has evolved into understanding the role of fire on interaction diversity in the fire-adapted long leaf pine forests of the southern US. We found increased plant diversity with more frequent fires and that generalist herbivores are crucial in maintaining interaction network resilience. Currently, in collaboration with colleagues in Ecuador, we are investigating the role of treefall gaps and fire within Indigenous forest practices.
Understanding the impacts of disturbance in altering diversity and multitrophic interactions has been a cornerstone of ecological research for decades. My early research as a graduate student quantified the effects of treefall gaps on bottom-up and top-down interactions in a lowland tropical forest. This research focus on disturbance is ongoing and has evolved into understanding the role of fire on interaction diversity in the fire-adapted long leaf pine forests of the southern US. We found increased plant diversity with more frequent fires and that generalist herbivores are crucial in maintaining interaction network resilience. Currently, in collaboration with colleagues in Ecuador, we are investigating the role of treefall gaps and fire within Indigenous forest practices.
