John W Rowe, Ph.D.
Chair and Professor of Biology
Joined Alma College Faculty in 2002
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- B.S.. Biology, Central Michigan University (1985)
- M.S., Zoology, Eastern Illinois University (1987)
- Ph.D., Ecology and Evolutionary Biology, University of Nebraska-Lincoln (1992)
My main research interest is life-history evolution and ecology of reptiles, particularly that of freshwater turtles. My earliest work involved activity and movements of Blanding's Turtle (Emydoidea blandingii) in Northeastern Illinois during the late 1980s. Subsequently, my dissertation involved comparative life histories of Western Painted Turtles (Chrysemys picta bellii) in floodplain and sandhills lake habitats in western Nebraska. In that work, I focused on the egg size - clutch size tradeoff, growth rates and body size, morphometric variation, and lipid content of eggs and lipid utilization and biochemistry during development. During that time, I also conducted studies on Blanding's Turtle life-histories and collaborative studies of lizard ecology.
Since the summer of 1994, I have maintained a long-term research program on Midland Painted Turtles (Chrysemys picta marginata) of the Beaver Island Archipelago in northern Lake Michigan. At Miller's Marsh on Beaver Island, my students and I have focused on various aspects of reproductive ecology and life-histories. We have published our work on variation in reproductive traits and age-and-size at maturity in female turtles as well as on nest-site fidelity, nesting success, and nesting movements. In 1999 and 2000, the spatial ecology/home range size and impacts (or lack thereof) of temperature and weather variations on daily activity/movements were assessed. Using surgically implanted radio-transmitters, we more recently (2003-2005) assessed body temperature variation as it impacts activity and is impacted by environmental temperatures during aquatic and nesting activity in adult turtles. During the summers of 2004 and 2005, we used thermally-sensitive carapace-mount radio-transmitters to study the spatial and thermal ecology of juvenile turtles.
We have also studied painted turtles on nearby Garden Island, where turtles live in Lake Michigan bays as well as in inland wetlands. We found that turtles in Lake Michigan bays tend to be larger and nearly carnivorous in their diets when compared to turtles from Miller's Marsh. Also, Lake Michigan turtles, which live on light algae/sand-colored substrates tend to be lighter in color than turtles from black, muck-bottomed inland wetlands. We hypothesize that lighter color may facilitate crypsis on sand and darker color on muck-bottomed substrates. In the laboratory, we found that both painted and red-eared slider turtles will develop relatively dark integuments when hatchlings were placed on a dark substrate as compared to individuals reared on a white substrate. Therefore, the degree of melanization may be a phenotypically plastic trait that facilitates crypsis on variable substrates.
In addition to the Painted Turtle studies, we have also conducted studies of activity, movements and home range size in Common Musk Turtles (Sternotherus odoratus) in southwestern Michigan. We found that stinkpot turtles are active around the clock and concentrate their activities in core areas on the margins of the lakes. Also in southwestern Michigan, we have begun studies of Spotted Turtle (Clemmys guttata) ecology in a large fen habitat and a bog habitat.
- J.W. Rowe and K. Bowen. "Diet of Midland Painted Turtles (Chrysemys picta marginata) in a Northern Lake Michigan Bay." Herpetological Review. 36:382-384