Research Interests
Plant
pathogens are often invoked as an important mechanism for controlling tree
seedling growth and survival. Their early life stage effects could ultimately
serve an critical role in shaping forest community structure and maintaining
tree species diversity. Despite their potential importance, many questions
remain about the role and identity of pathogens in temperate forest ecosystems.
The goals of this research are to:
(1) identify the fungi and oomycetes that may cause seedling disease and
mortality for a number of important southeastern US forest tree species;
and
(2) test a classic ecological hypothesis (the Janzen-Connell hypothesis)
which predicts that host-specific pathogens drive spatial patterns of seedling
recruitment.
My research uses a combination of field experiments, laboratory analyses,
and statistical modeling to address these questions. It takes place in mixed-species
plots of tree seedlings planted along a natural soil moisture gradient in
two mixed hardwood stands in North Carolina. These field sites have been
well-characterized with respect to tree demography and relevant abiotic
covariates such as light and soil moisture. Fungi and oomycetes are isolated
and identified using both cultural as well as DNA-based molecular methods.
We then use a hierarchical Bayesian modeling framework to infer incidence
of potential pathogens, infection rates, and impacts on seedling survival.
