Cynthia Chang

Post-doctoral Associate
Department of Biology
University of Florida
312 Carr Hall
Gainesville, FL, 32611
Email: cynthiacchang@gmail.com

Education

2012     Ph.D. Yale University, Ecology and Evolutionary Biology
2007     M.S. Yale University, Ecology and Evolutionary Biology
2005     B.S. University of Maryland-College Park, Environmental Science and Policy

Cynthia's CV

Dissertation Research

Role of diversity at the community and population level in productivity and invasion of the tallgrass prairie ecosystem

Understanding the importance and maintenance of biological diversity in ecological communities holds significant relevance for both the advancement of ecological theory as well as management ecosystems in a time of unprecedented, human-driven global change. Diversity at the species level has long been proposed to be a key driver in ecosystem function, such as productivity and invasion resistance; however species richness alone does not completely explain these relationships. Dominant species are by definition the most ubiquitous in the ecosystem, and as such, trait variation in this population could have the largest impact on ecosystem function. While some recent studies have shown the importance of genotypic diversity in dominant species, no study has yet examined the relative impacts of genetic, species, and trait diversity in an intact, natural system where individuals naturally co-occur. My dissertation research examines underlying relationships between genetic, species, trait diversity and exploring how this diversity impacts productivity and invasion resistance under different fire frequency in intact tallgrass prairie.

I hope to address the following 4 questions in my research:

1. What are the relative effects of genotypic, trait, and community diversity on productivity under different fire frequency?
2. What are the relative effects of genotypic, trait, and community diversity on invasion resistance?
3. What is the role of fire on genotypic diversity of the dominant species, species diversity, and productivity in the tallgrass prairie?
4. How does light, water, and nitrogen avaliability impact the competitive interaction between A. gerardii genotypes grown in the greenhouse?

Previous Research

Patterns of selection of native and non-native populations of Mimulus guttatus grown in drought and non-drought conditions.

Understanding the evolutionary mechanisms behind the spread of introduced species in new habitats allows us to better understand the invasion process. To date, we have limited data on differences or similarities for the same species in both native and non-native environments in patterns of natural selection. Additionally, we lack an understanding of the role of phenotypic plasticity (the ability of a single genotype to vary its phenotype across environments) in the differences among individuals observed in native and non-native populations.

In this project, native populations of Mimulus guttatus from California and established populations from outside the natural range were grown in a common greenhouse environment to disentangle the influence of local field environment and genetics among populations. Differences in patterns of selection in native and non-native populations were studied by correlating fitness to certain phenotypic and morphological traits hypothesized to be associated with invasive success. Patterns of selection in drought and non-drought conditions were measured, representing variation in one important component of the abiotic field environment of M. guttatus.

* undergraduate research conducted under direction of Dr. Michele Dudash (University of Maryland-College Park) and Dr. Courtney Murren (College of Charleston)

Publications

Chang, C.C. and M.D. Smith. 2011. Invasion of an intact plant community: the role of population vs. community level diversity. (in press Oecologia)

LaPierre, K. J., S. Yuan, C.C. Chang, M.L., Avolio, L.M. Hallett, T. Schreck, M.D. Smith. 2011. Explaining temporal variation in aboveground productivity in a mesic grassland: The role of climate and flowering. Journal of Ecology. 99: 1250-1262

Avolio, M.L., C.C. Chang, M.D. Smith. 2011. Assessing the fine-scale genetic diversity of Andropogon gerardii in intact tallgrass prairie. American Midland Naturalist. 165(2):211-224

Murren, C. J., C. C. Chang, and M. R. Dudash. 2009. Patterns of selection of two North American native and non-native populations of Monkeyflower (Phyrmaceae). New Phytologist 183:691-701.