Research Interests
In general, my research can be divided into two not entirely distinct agendas. The first is aimed at the general question of what ecological and evolutionary processes are responsible for the assembly of ecological communities through eco-evolutionary time. My second research emphasis is deals with abundance-size distributions from a variety of perspectives ranging from what processes generate size distributions to how size distributions influence ecosystem processes (i.e. carbon storage and flux). I provide further details of specific projects below
Eco-Evolutionary Modeling
The primary focus on my current work on community assembly is in the context of eco-evolutionary models rooted in the metabolic theory of ecology. Eco-evolutionary models provide the opportunity to generate process-based predictions for gradients in community structure because they simultaneoulsy account for the key processes affecting community assembly. That is, ecological interactions, phenotypic diversification, and ecosystem dynamics are allowed to continuously emerge and dynamically feedback on each other. This provides a more holistic perspective than previous theoretical endeavors especially from the perspective of species richness gradients.
Species Richness-Temperature Gradients
Rigorous, process-based theory for the generation and maintenance of species richness gradients has historically been lacking. The eco-evolutionary paradigm provides the means to significantly advance species richness theory. In this context I am currently asking "How does environmental temperature influence realized species richness?" The short answer is that temperature can act to increase species richness in some contexts and has no effect in other contexts. More generally, the key to understanding the influence of temperature is to consider how species interactions interact with the abiotic environment and evolutionary processes. This work is currently being extended and preliminary results suggest that species richness can causally increase or decrease with temperature. The power of the eco-evolutoinary approach is that we can provide testable, process-based hypotheses for a broad spectrum of species richness-temperature gradients.
Stochastic and Deterministic Community Assembly
I am just beginning to think about the continuum between stochastic and deterministic processes for community assembly. There is great utility in formalizing this continuum for a range of questions and applications ranging from species richness gradients to applied issues such as the influence of global change on community structure.
Adaptive Diversification and Community Structure of Obligate Mutualisms
The persistance of cheating within mutualistic interactions has long been an evolutionary puzzle and recent work has provided a number of hypotheses to account for this repeated observed pattern. With Regis Ferriere and Mathias Gauduchon, we have been exploring how organismal traits of obligate mutualists effects the persistance of cheaters and, more generally, phenotypic diversification across the mutualistic-cheater continuum. The primary conclusion of this work is that organismal traits can strongly influence the macroevolution patterns of the mutualist-cheater continuum including species richness, the range of phenotypes observed, the rate of diversification, and the degree of phenotypic differentiation.
Abundance-Size
Distributions
Forest Biomass/Carbon Storage
Using a database of forest plots (SALVIAS) I have examined the analytical link between size distributions and total community biomass. The prediction of this approach works surprisingly well, but an attempt to extend this to patterns of biomass related to climate proved somewhat more difficult. In essense, there is little correlation between forest biomass and a variety of climate metrics. This has the important implication that global climate change may have little direct influence over carbon stored in the woody component of forests across the globe.
Wood Density and Forest Biomass
This work isn't directly related to size distributions, but could be linked indirectly. Anyways, I have shown that contrary to popular wisdom, forest biomass does not necessary increase with wood density at the community scale. This has important implications for global change/future carbon dynamics. This is such that some forests are predicted to decline in wood density. My work shows that the corresponding change in stored carbon is context dependent such that biomass is predicted to increase or decrease with declining wood density, depending on forest identity.
Size Distributions Within Model Food Webs
This work is again in the context of the eco-evolutionary models I am working on. Basically, I am attempting to determine what features of the biotic and abiotic landscape determine the scaling of abundance with body size and subsequently how the realized size distribution relates to whole ecosystem energy flux. This work is in its infancy, look for updates in the future.
Other Size Distribution Projects
I am currently pursuing a number of additional size distribution projects with Ethan White. However, these are too preliminary to warrent a fruitful elaboration here. I will update this section as more definitive results emerge
Using a database of forest plots (SALVIAS) I have examined the analytical link between size distributions and total community biomass. The prediction of this approach works surprisingly well, but an attempt to extend this to patterns of biomass related to climate proved somewhat more difficult. In essense, there is little correlation between forest biomass and a variety of climate metrics. This has the important implication that global climate change may have little direct influence over carbon stored in the woody component of forests across the globe.
Wood Density and Forest Biomass
This work isn't directly related to size distributions, but could be linked indirectly. Anyways, I have shown that contrary to popular wisdom, forest biomass does not necessary increase with wood density at the community scale. This has important implications for global change/future carbon dynamics. This is such that some forests are predicted to decline in wood density. My work shows that the corresponding change in stored carbon is context dependent such that biomass is predicted to increase or decrease with declining wood density, depending on forest identity.
Size Distributions Within Model Food Webs
This work is again in the context of the eco-evolutionary models I am working on. Basically, I am attempting to determine what features of the biotic and abiotic landscape determine the scaling of abundance with body size and subsequently how the realized size distribution relates to whole ecosystem energy flux. This work is in its infancy, look for updates in the future.
Other Size Distribution Projects
I am currently pursuing a number of additional size distribution projects with Ethan White. However, these are too preliminary to warrent a fruitful elaboration here. I will update this section as more definitive results emerge
Previous Research
My past research endeavors span a broad array of topics including UV radiation on amphibians, color change in tree frogs, trophic interactions within pond communities, limilogical and biotic description of lake ecosystems, and the monitoring of chinook salmon populations.