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Christopher Stieha

Education

Master's in Biology 2008, University of Kentucky

BS Biology, BA Chemistry 2003, University of Kentucky

Research

As global climate change and human encroachment fragment habitats, understanding the spatial mechanisms for the maintenance of competing species and individuals is vital for conservation. For my dissertation research, I combine mathematical models and field research to understand the maintenance of both sexes in a clonal plant with extreme intersexual competition.  I use mathematical models to develop hypotheses and predictions for the maintenance of the sexes under intense competition, which I then test at various spatial scales using the variation among populations and among streams in the field.  Populations of the plant Marchantia inflexa can exist with only females, only males, or with both sexes. Streams containing aggregates of populations can contain only females, only males, or both sexes.  I am particularly interested in the maintenance of the sexes considering the spatial configuration of aggregates of populations, such as size of the populations, distance between populations, and the density of populations. Taking a spatial approach allows me to understand the real world as well as understand the importance of interactions between populations and the effects of fragmentation on the maintenance of the sexes.

Graduate Training

Aggressive Interactions between Two Plant Species - Fulbright Fellowship

Organization of Tropical Studies - Costa Rica

Selected Publications:

Rohr, J.R., Sesterhenn, T., Stieha, C. 2011. Will climate change reduce the effects of a pesticide on amphibians?: Partitioning effects on exposure and susceptibility. Global Change Biology. 17:657-666, doi: 10.1111/j.1365-2486.2010.02301.x

Groen, K.E., Stieha, C., Crowley, P.H., and McLetchie, D.N. 2010. Sex-specific plant responses to light and canopy openness: Implications for spatial segregation of the sexes. Oecologia. 162(3): 561-570.

Groen, K.E., Stieha, C., Crowley, P.H., and McLetchie, D.N. 2010. Sex-specific plant responses to two light levels in the liverwort Marchantia inflexa. Bryologist. 113(1): 81-89.

García-Ramos, G., Stieha, C., McLetchie, D.N., and Crowley, P. 2007. Metapopulation Sex Ratio Dynamics and Coexistence of the Sexes under Asymmetrical Competition. J. Ecology. 95:937-950

Crowley, P.H., Stieha, C.R., and McLetchie, D.N. 2005. Overgrowth Competition, Fragmentation and Sex-Ratio Dynamics: A Spatially Explicit, Sub-Individual Based Model. J. Theor. Biol. 233:25-42.