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Ryan Thum, Ph.D.

Assistant Professor

224 Lake Michigan Center
740 W. Shoreline Dr.
Muskegon, MI 49441
(616) 331-3989
thumr@gvsu.edu

Areas of Interest:

• Molecular Ecology
• Invasion Biology

My general fields of interest encompass evolutionary and molecular ecology, with a specific emphasis on invasive aquatic species.

The current focus of my laboratory is the evolutionary ecology of invasiveness and herbicide resistance in aquatic plants, with a particular emphasis on hybridization and evolution.  These projects include studies of: the genetic basis of herbicide response, population structure, molecular evolution of candidate genes for herbicide response, and gene expression differences.  There are a wide variety of opportunities for students and post-docs to develop collaborative projects in this area.  Additional opportunities are available for students in other research areas.  Just call or email.

For a brief tour of research and teaching, Click Here to check out the GVSU Center for Scholarly and Creative Excellence short video of my lab. 

Education

• Ph.D. - Dartmouth College (2004)
• B.S. - Florida State University (1998)
• Postdoctoral Fellow - Cornell University (2004-2006)
• University of Illinois at Urbana-Champaign (2006-2007)

Submitted manuscripts

• Tavalire, H. F., Bugbee, G., LaRue, E. A., Thum, R. Hybridization and the evolution of invasiveness: Introduced hybrids are more invasive than introduced parental lineages of variable-leaf watermilfoil. Submitted to Evolutionary Applications (November 2011).

• Thum, R.A., Heilman, M.A. et al. (7 other authors). Field and laboratory documentation of reduced fluridone sensitivity by a hybrid watermilfoil biotype (Myriophyllum spicatum x Myriophyllum sibiricum). Submitted to Journal of Aquatic Plant Management (September 2011).

• Allen, MR, Thum, RA, VanDyke, JN, and Cáceres, CE. Trait sorting in Daphnia colonizing recently-formed lakes. Submitted, Freshwater Biology.

Publications

• Zuellig, M.P. and R. A. Thum. Multiple introductions of invasive Eurasian watermilfoil and recurrent hybridization with native northern watermilfoil in North America. In press, Journal of Aquatic Plant Management (October 2011).
• Thum, R.A., A.T. Mercer, and D. Wcisel. Loopholes in the regulation of invasive species?: Genetic identifications identify the sale of invasive and uncharacterized watermilfoils. In press (August 2011), Biological Invasions: DOI: 10.1007/s10530-011-0130-8.
• Poovey, A. G., Mudge, C. R., Thum, R., James, C., Getsinger, K. D. Evaluations of contact aquatic herbicides for controlling two populations of submersed flowering rush.  In press (January 2012), Journal of Aquatic Plant Management.
• Thum, R.A., M. P. Zuellig, M.E. Moody, C. Vossbrinck, and R.L. Johnson. 2011. Molecular markers reconstruct the invasion history of variable leaf watermilfoil (Myriophyllum heterophyllum) and distinguish it from closely related species. Biological Invasions 13: 1687-1709.
• LaRue, E.A., C.R. Ruetz, III, M.B. Stacey, and R.A. Thum. 2011. Population genetic structure of the invasive round goby in Lake Michigan: implications for natural versus anthropogenic dispersal after introduction. Hydrobiologia 66: 71-82.
• Allen, M., Thum, R.A., Caceres, C. 2010. Does resource monopolization explain genetic differentiation in Daphnia populations? Molecular Ecology 19:3076-3087.
• Thum, R.A., and J.T. Lennon. 2010. Comparative ecological niche models predict the invasive spread of variable-leaf milfoil (Myriophyllum heterophyllum) and its potential impact on closely related native species. Biological Invasions 12: 133-143.
• Thum, R.A., and Harrison, R.G. 2009. Deep genetic divergences among morphologically similar and parapatric Skistodiaptomus (Copepoda: Calanoida: Diaptomidae) challenge the hypothesis of Pleistocene speciation. Biological Journal of the Linnean Society 96: 150-165.
• Thum, R.A., and Derry, A. 2008. Taxonomic implications for diaptomid copepods based on contrasting patterns of mitochondrial DNA sequence divergences in four morphospecies. Hydrobiologia 614: 197-207.
• Thum, R.A. 2007. Reproductive interactions and the maintenance of parapatry in Skistodiaptomus copepods. Oikos 116: 759-768.
• Thum, R.A., and Lennon, J.T. 2006. Is hybridization responsible for aggressive growth of non-indigenous water-milfoils? Biological Invasions 8: 1061-1066.
• Thum, R.A., Lennon, J.T., Connor, J., and A.P. Smagula. 2006. A DNA fingerprinting approach for distinguishing among native and non-native milfoils. Lake and Reservoir Management 22: 1-6.
• Thum, R.A, and Stemberger, R.S. 2006. Pure spatial and spatially-structured environmental variables explain copepod range limits. Canadian Journal of Fisheries and Aquatic Sciences 63: 1397-1404.
• Turgeon, J., Stoks, R., Thum, R.A., Brown, J.M., and McPeek, M.A. 2005. Simultaneous quaternary radiations of three damselfly clades across the holarctic. American Naturalist 165: E78-E107.
• Thum, R.A. 2004. Using 18S rDNA to resolve diaptomid copepod (Copepoda: Calanoida: Diaptomidae) phylogeny: an example with the North American genera. Hydrobiologia 519: 135-141.
• James, F.C., C.A. Hess, B.C. Kicklighter, and R.A. Thum. 2001. Ecosystem management and the niche gestalt of the red-cockaded woodpecker in longleaf pine forests. Ecological Applications 11: 854-870.

Invited publications -

• CABI. Myriophyllum heterophyllum [original text by R.A. Thum and M.P. Zuellig]. Wallingford, UK: CABI (*This is an account of invasive variable leaf water-milfoil for a global invasive species compendium); available at www.cabi.org/isc.

Teaching

• Molecular Ecology (Winter term each year)
• Independent Research Experience for course credit (by request)