Current Address:

Section of Evolution and Ecology
University of California
Davis, CA 95616

I am interested in the evolutionary ecology, and conservation of amphibians.  My dissertation research focused on patterns of migration, dispersal, and gene flow of gray treefrogs (Hyla versicolor) and spotted salamanders (Ambystoma maculatum) in central Missouri using artificial arboreal refugia, radiotelemetry, and experimental tank arrays.

Currently, I am studying the dynamics of a tiger salamander (A. tigrinum mavortium x A. californiense) hybrid zone in the central valley of California using diagnostic single nucleotide polymorphism (SNP) loci to investigate genomic variation in responses to introgression and environment-dependent invasion success.  For more information on current and past research please visit my UC Davis page.

Johnson, J.R., R.D. Mahan and R.D. Semlitsch.  In Review.  Terrestrial microhabitat use by gray treefrogs (Hyla versicolor) in oak-hickory forests. Forest Ecology and Management.

Johnson, J.R., J.H. Knouft and R.D. Semlitsch. In review. Sex and seasonal differences in the spatial terrestrial distribution of gray treefrog (Hyla versicolor) populations. Biological Conservation.

Johnson, J.R. and R.D. Semlitsch. In review. Effect of inter-pond distance and matrix habitat on movements of the gray treefrog in experimental pond arrays. Landscape Ecology.

Mahan, R.D. and J.R. Johnson. In press. Diet of the gray treefrog (Hyla versicolor) in relation to foraging site location.  Journal of Herpetology.

Johnson, J.R., 2006.  Success of intracoelomic radiotransmitter implantation in the treefrog, Hyla versicolor.  Lab Animal 35:29-33.

Johnson, J.R. 2005. A novel arboreal pipe-trap designed to capture the gray treefrog (Hyla versicolor). Herpetological Review 36:274-277.

Johnson, J.R.  2005. Gray treefrog (Hyla versicolor) record size. Herpetological Review 36:302.

Daniel, R.E. and J.R. Johnson. 2004. New size records for three species of Missouri amphibians. Annual Newsletter of Missouri Herpetological Association 17:14.

Johnson, J.R. 2004. Fall breeding of the southern leopard frog (Rana sphenocephala) in central Missouri. Annual Newsletter of Missouri Herpetological Association 17:14.

Johnson, J.R. and R.D. Semlitsch. 2003. Defining core habitat of local populations of the gray treefrog (Hyla versicolor) based on choice of oviposition site. Oecologia 137:205-210.

Phillips, C.A., J.R. Johnson, M.J. Dreslik and J.E. Petzing. 2002. Effects of hydroperiod on recruitment of mole salamanders (Genus Ambystoma) at a temporary pond in Vermilion County, Illinois. Transactions of the Illinois State Academy of Science 95:131-139.