What I do
My work addresses fundamental questions in population, community, and evolutionary ecology. I am most interested in questions to do with system dynamics (changes over time) and the processes that drive them. Accordingly, much of my work uses a combination of mathematical modeling and experiments in tractable model systems such as laboratory microcosms. I use mathematical models because ecological and evolutionary systems are complex and nonlinear. It's hard to develop and test rigorous hypotheses without mathematical help. I use microcosms because their high control and replicability allows powerful, rigorous experiments that would not otherwise be possible. For instance, in microcosms we often can isolate the effects of a single process on system dynamics, which may well be impossible in nature.
My lab is currently
funded by an NSERC Discovery Grant.
Below are the main lines of research
currently going on in the lab.
This is a collaboration with David
The aim of this project is to explain spatial synchrony.
populations of the same species, and coexisting populations of
different species, often fluctuate synchronously, even though they're
hundreds or even thousands of km apart. That's amazing! We have
theories of why that happens, but those theories are hard to test in
nature because it's impossible to do experiments at the right spatial
and temporal scales. You can't, say, manipulate the weather across all
of Canada and then wait a century to see what happens to the synchrony
of lynx-hare cycles. The solution is to scale nature down and do
experiments in protist microcosms.
Publications: Vasseur & Fox 2007 Ecol. Lett., Vasseur & Fox 2009 Nature, Fox et al. 2011 Ecol. Lett., Fox et al. 2013 PLoS One
Local adaptation in time and space
Environmental conditions vary in space,
imposing contrasting selection pressures that favor different
phenotypes and genotypes. That can cause local adaptation, with each
environment being dominated by the organisms that are fittest locally.
An analogous process can occur in ecology, with different species
competitively dominating in different environments. Local adaptation is
a powerful way to maintain diversity. But the environment also varies
in time. Can you have local adaptation in time, with different
locally-adapted genotypes or species dominating at different times and thereby coexisting? The simplest
theoretical models say no: all else being equal, a trait that makes you
well-adapted to today's conditions at the cost of making you
poorly-adapted to tomorrow's conditions will not be favored by
selection (in contrast to a spatially-varying environment). Of course,
the world might be more complicated than the simplest theory assumes.
I'm testing these ideas using lake bacteria. Water chemistry varies a
lot among lakes, and over time. By freezing bacterial isolates and
water samples at -80 C, we can use the freezer as a 'time
machine'. That is, we can reciprocally transplant bacteria back into
water from the past, and forward into water from the future. Pilot data
suggest geographic variation in the strength of local adaptation (and maladaptation) in space and time.
I'm currently seeking a graduate student interested in expanding this
work to many more sites and times.
Publications: Fox & Harder in press Evolution