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How Life Responds to Seasons
The annual cycle of seasons is a ubiquitous and powerful phenomenon driving myriad patterns in nature across our planet. Broadly, my research focuses on the ways organisms respond to seasonality; both by evolving and/or adopting behaviors that make them more successful in seasonal environments. I use a combination of theoretical and empirical approaches to ask why particular strategies are successful and why we see so much diversity in strategies across species.
I'm particularly interested in the association between life history tradeoffs and seasonal resource dynamic: How do the dynamics of these cyclical resource fluctuations constrain or promote particular life history strategies? Life history theory is fundamental to understanding organisms’ evolved responses to their environments. An organism’s life history encompasses the set of adaptive traits, and the tradeoffs between those traits, that produce fitness. Despite the central importance of life history theory to organismal biology, ecology, and evolution, the mechanisms driving the observed diversity in life histories remain elusive.
In collaboration with colleagues at University of Colorado Denver, I'm working on a bioenergetic model to generate new predictions about the relationship between resource dynamics and the diversity of viable life histories. The metabolic basis of our model provides a compelling mechanistic link to well-known emergent macroecological patterns that still elude clear explanation, such as the latitudinal biodiversity gradient.
The annual cycle of seasons is a ubiquitous and powerful phenomenon driving myriad patterns in nature across our planet. Broadly, my research focuses on the ways organisms respond to seasonality; both by evolving and/or adopting behaviors that make them more successful in seasonal environments. I use a combination of theoretical and empirical approaches to ask why particular strategies are successful and why we see so much diversity in strategies across species.
I'm particularly interested in the association between life history tradeoffs and seasonal resource dynamic: How do the dynamics of these cyclical resource fluctuations constrain or promote particular life history strategies? Life history theory is fundamental to understanding organisms’ evolved responses to their environments. An organism’s life history encompasses the set of adaptive traits, and the tradeoffs between those traits, that produce fitness. Despite the central importance of life history theory to organismal biology, ecology, and evolution, the mechanisms driving the observed diversity in life histories remain elusive.
In collaboration with colleagues at University of Colorado Denver, I'm working on a bioenergetic model to generate new predictions about the relationship between resource dynamics and the diversity of viable life histories. The metabolic basis of our model provides a compelling mechanistic link to well-known emergent macroecological patterns that still elude clear explanation, such as the latitudinal biodiversity gradient.
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How and why do migrations evolve?
Migration is one among many possible adaptations to seasonality. Despite the phenomenon being so widespread across taxa, even in very well studied groups, such as birds, researchers continue to debate the ultimate drivers of the phenomenon. Are migratory organisms driven to seek ephemeral resource abundances or to escape periods of scarcity? Both? With collaborators across the U.S. I'm using animal tracking data, combined with remote-sensed proxies for food resources to test competing hypotheses about the ultimate ecological drivers of migration.
Migration is one among many possible adaptations to seasonality. Despite the phenomenon being so widespread across taxa, even in very well studied groups, such as birds, researchers continue to debate the ultimate drivers of the phenomenon. Are migratory organisms driven to seek ephemeral resource abundances or to escape periods of scarcity? Both? With collaborators across the U.S. I'm using animal tracking data, combined with remote-sensed proxies for food resources to test competing hypotheses about the ultimate ecological drivers of migration.
Migratory Connectivity of a Long-distance Migrant Owl
I am working with the Smithsonian Institute’s Migratory Connectivity Project and several collaborators to better understand the migratory behaviors of Flammulated Owls across the species' range. Generally, our understanding of the biology of migratory populations is limited to the breeding season only, leaving large gaps in our understanding of what is required to maintain healthy populations of many species. (e.g. resource requirements may vary seasonally, species may face survival “bottlenecks” on migration or during winter). We are now tracking these owls year-round with micro-GPS technology to increase our understanding of their full life cycle ecology. We are also combining the direct tracking approaches with intrinsic molecular markers, such as stable isotopes, to reconstruct the breeding-grounds origins of birds captured during the winter (including historical museum speciemens
I am working with the Smithsonian Institute’s Migratory Connectivity Project and several collaborators to better understand the migratory behaviors of Flammulated Owls across the species' range. Generally, our understanding of the biology of migratory populations is limited to the breeding season only, leaving large gaps in our understanding of what is required to maintain healthy populations of many species. (e.g. resource requirements may vary seasonally, species may face survival “bottlenecks” on migration or during winter). We are now tracking these owls year-round with micro-GPS technology to increase our understanding of their full life cycle ecology. We are also combining the direct tracking approaches with intrinsic molecular markers, such as stable isotopes, to reconstruct the breeding-grounds origins of birds captured during the winter (including historical museum speciemens
Simulation models and the method of multiple working hypotheses
In 1890 Thomas Chamberlin published an article in Science emploring researchers to consider multiple working hypotheses in any inferential endeavor. Chamberlin contended that doing so strengthened inference and guarded against biased outcomes predicated on a researcher's favored ideas. This article is the single most requested reprint the journal Science ever published. Despite its popularity and the critical message it conveys, most researchers in ecology and evolutionary biology still fail to consider multiple hypotheses. I have developed a framework that seeks to further enable researchers to overcome barriers to considering multiple hypotheses in their work. Specifically, I have shown that simulation modeling during the design phase of research can be a powerful tool to avoid collecting data that cannot be used to provide conclusive support for a given hypothesis (model identifiability). My R package checkyourself provides simple code for basic examples of this process in movement ecology and species distributions.
In 1890 Thomas Chamberlin published an article in Science emploring researchers to consider multiple working hypotheses in any inferential endeavor. Chamberlin contended that doing so strengthened inference and guarded against biased outcomes predicated on a researcher's favored ideas. This article is the single most requested reprint the journal Science ever published. Despite its popularity and the critical message it conveys, most researchers in ecology and evolutionary biology still fail to consider multiple hypotheses. I have developed a framework that seeks to further enable researchers to overcome barriers to considering multiple hypotheses in their work. Specifically, I have shown that simulation modeling during the design phase of research can be a powerful tool to avoid collecting data that cannot be used to provide conclusive support for a given hypothesis (model identifiability). My R package checkyourself provides simple code for basic examples of this process in movement ecology and species distributions.
Resource Selection in a Spatiotemporally Heterogeneous Environment
I use a small migratory owl (Flammulated Owl; Psiloscops flammeolus) as a model system for studying animal movement behavior. The old-growth forests the species inhabits in North America are highly fire dependent and historically would experience frequent but low severity fires that would “clean out” the underbrush but leave the forest canopy intact. Climate change and recent management practices are moving these fire regimes towards much higher severity fire behavior which results in destructive stand replacing fires which drastically modify the species’ habitat. I am working with the U.S. Forest Service in Colorado’s San Juan Mountains to use archival GPS technology to study habitat use before and after a prescribed fire, to better understand how this species (and other species that inhabit these environments) might respond to changing fire regimes. This study will leverage approaches suggested by the simulation project.
I use a small migratory owl (Flammulated Owl; Psiloscops flammeolus) as a model system for studying animal movement behavior. The old-growth forests the species inhabits in North America are highly fire dependent and historically would experience frequent but low severity fires that would “clean out” the underbrush but leave the forest canopy intact. Climate change and recent management practices are moving these fire regimes towards much higher severity fire behavior which results in destructive stand replacing fires which drastically modify the species’ habitat. I am working with the U.S. Forest Service in Colorado’s San Juan Mountains to use archival GPS technology to study habitat use before and after a prescribed fire, to better understand how this species (and other species that inhabit these environments) might respond to changing fire regimes. This study will leverage approaches suggested by the simulation project.