I am generally interested in how ecological patterns develop in response to the energy use of individuals and how environmental feedbacks affect the energy use of individuals.  I am especially interested in developing general understanding about energy use and ecology that can inform sustainability and conservation efforts.  I am exploring these ideas in several ways:










1.  My dissertation research has focused on the feedback between population size and individual energy use, and how these relationships translate into population dynamics.  I am investigating these ideas with both models and experiments.  My study systems are microcosm populations of single-celled eukaryotes (protists).  I have found striking patterns of density-dependent per-capita metabolic rate (which I view as an instantaneous energy budget) in a variety of protist species.  For Tetrahymena pyriformis, a heterotroph that can be grown in axenic conditions, I have found strong metabolic dependence of division and death rates.  In a nutshell, I am finding that populations are regulated by the metabolic rate of individuals.  This finding has spurred me to explore the consequences of temperature, predation, and competition on per-capita metabolic rates and how these environmental feedbacks influence population outcomes.



2.  I am also curious as to whether the maximum power principle (MPP) actually captures the essential thermodynamic drive of living organisms, and how to model the principle so that it can be used to understand ecological patterns.  The MPP is an old idea and seems logical, but making it really useful is a challenge. See my recent paper in Oikos on the MPP and competitive outcomes.

3.  I am collaborating with anthropologists at UNM on studies of population regulation and stability of human hunter-gatherers, with special emphasis on understanding how humans have been so successful as a species despite their slow life histories.














4.  Another area of interest to me is the energetics of migrating birds and how migration patterns develop in response to the energy needs and prey availability that birds experience along the migration route.  This is a long-term interest of mine that I have slowly been investigating over the last ten years or so, with continuing field work in the Manzano Mountains of New Mexico.