Current Research
I am currently looking for motivated undergraduate assistants to help with a number of different ongoing research projects - please email me at christian.brown1@uga.edu if interested!
The central question I am investigating is: What are the factors causing the distribution limits of eastern US temperate tree species at their opposing latitudinal edges? Understanding the potentially different causes of distribution limits at opposing latitudinal edges will enable us to better predict future migration patterns of tree species with ongoing global climate change. I am using a combination of field and lab experiments, along with quantitative modeling approaches using the wealth of pre-existing data available on US forests to address my questions:
1) A cross-latitude field experiment examining biotic and abiotic impacts on tree population growth featuring sites from Archbold Biological Research Station (Venus, FL) to Harvard Forest (Petersham, MA).
2) Constructing joint species distribution models to identify shifts in biotic and abiotic species associations across a latitude gradient
3) Constructing structural equation models for species interactions at opposing latitudinal distribution limits.
4) Constructing range-wide, mechanistic metapopulation models with the aim of parameterizing the models to be responsive to changes in the abiotic and biotic environment.
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The Smithsonian Environmental Research Center sits perfectly at the northern edge of many southeastern temperate tree species' distributions.
Master's Research
My master's research involved assessing the restoration potential of a high-elevation tree species red spruce (Picea rubens) under current and future predicted climate change. I used a combination of field sampling and statistical techniques to create a comprehensive view of red spruce restoration potential:
1) I created a distribution model and a habitat suitability model for red spruce and compared the two models to establish the spatial extent to which red spruce could expand.
2) I surveyed several red spruce stands to quantify the extent of regeneration taking place in the Central and Southern Appalachian Mountains and to investigate if stands are expanding beyond their current canopies
3) I used climate change simulations to approximate the potential effects of climate change on red spruce regeneration throughout the 21st century
Undergraduate Research
The 2nd highest peak in Virginia, Whitetop Mountain: one of the few areas in the central and southern Appalchians where red spruce is the dominant tree species. Elevation 5520 ft.
As an undergraduate I was involved in 2 separate projects:
1) I assessed the sugar content of nectar collected from several wildflower species native to the Southern Appalachian mountains for use in a resources collected model for the common eastern bumblebee (Bombus impatiens)
2) I created a Lefkovitch matrix model to simulate the effects of targeted management treatments of an invasive Japanese barberry (Berberis thunbergii) population in the Appalachian State University nature preserve.