Broadly, my research interests are molecular ecology (the use of molecular genetic tools to answer ecological questions), conservation biology, and herpetology. I am particularly interested in amphibians, as they can be important indicators of habitat degradation and other environmental disturbances (so-called “canaries in the coal mine”).
Work in my lab focuses on the use of molecular tools for two major purposes. First, genetic analyses can be highly informative regarding the conservation status of imperiled populations. For example, my graduate work used molecular data to quantify population isolation in marbled salamanders (Ambystoma opacum) and its relation to anthropogenic landscape modification. Similarly, my lab is currently working with David Mifsud on a project assessing population genetics (and effects of fragmentation, i.e., dams) and conservation status of the mudpuppy (Necturus maculosus). Students in my lab can propose to use similar tools to address related questions in conservation of reptiles and amphibians. For example, Patrick Terry used genetics to assess population structure and history of introduction in red-eared slider turtles (Trachemys scripta elegans), and Jeff Bartman plans to look at snake landscape genetics along an urban-rural gradient.
A second use of genetics in my laboratory is to aid in the identification of unisexual (all female) Ambystoma salamanders. These salamanders “steal” sperm from co-occurring species, resulting in numerous polyploid biotypes (genome combinations). This unique mode of reproduction, known as kleptogenesis, likely originated 5 million years ago. In order to explore the ecological consequences and conservation implications of this complex system, I am conducting experiments in conjunction with a capture-mark-recapture program at the University of Michigan’s Edwin S. George Reserve near Pinckney, Michigan.
Some of our recent publications are linked below.
Denton et al 2016. Differences in endurance and realized dispersal between sexual and unisexual salamanders. Functional Ecology. In press.
Greenwald et al 2016. Niche partitioning among sexual and unisexual Ambystoma salamanders. Ecosphere 7(11).
Teltser and Greenwald 2015. Survivorship of Ploidy-variable Unisexual Ambystoma Salamanders Across Developmental Stages. Herpetologica 71: 81-87.
Denton et al 2014. Evolutionary basis of mitonuclear discordance between sister species of mole salamanders (Ambystoma sp.). Molecular ecology 23: 2811-2824.
Greenwald and Gibbs 2012. A single nucleotide polymorphism assay for the identification of unisexual Ambystoma salamanders. Molecular Ecology Resources 12: 354-362.
Greenwald 2010. Genetic data in population viability analysis: case studies with ambystomatid salamanders. Animal Conservation 13: 115-122. Highlighted as the Featured Paper with three response commentaries.
Greenwald et al 2009a. Efficacy of land-cover models in predicting isolation of marbled salamander populations in a fragmented landscape. Conservation Biology 25: 1232-1241.
Greenwald et al 2009b. Landcover predicts isolation in Ambystoma salamanders across region and species. Biological Conservation 142: 2493-2500.
Bartoszek and Greenwald 2009. A population divided: railroad tracks as a barrier to gene flow in an isolated population of Marbled Salamanders (Ambystoma opacum). Herpetological Conservation and Biology 4: 191-197.