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Ecology professor expands 25-year (and counting) turtle study

by Scott MacDonald, CALS communications service intern

When you study turtles, you’re going to need quite a bit of patience. But for ISU ecology, evolution and organismal biology Professor Fred Janzen, just how much patience needed is still an ongoing question.

In 1988, then a doctoral student at the University of Chicago, Janzen began a study of sex-determining mechanisms in painted turtles along the Mississippi River at the Iowa-Illinois border. The Des Moines Register recently visited Janzen at the camp.

The project became a summer camp of sorts, a yearly six-week expedition for Janzen’s students to the riverbanks to locate, count, tag, measure and observe the turtles. Now in its 25th year, the camp continues, plus the team is working to develop four new ponds at the Horticulture Research Station north of Ames.

Career path started in Arizona desert

While Janzen understands what needs to go into a lengthy and painstaking study, he knows now that slow and steady wins the race.

Having grown up around the Midwest before his family settled in rural Wisconsin, Janzen attended North Central College in Naperville, Ill., where he struggled on a major and career path before finding passion in a zoology course. Switching to biology, Janzen took a three-week desert ecology field trip, which focused on saguaro cactus research at the Organ Pipe Cactus National Monument in southwestern Arizona. The trip was a turning point for him.

“I was focused. I was galvanized, excited,” Janzen said. “I realized, ‘Wow, this is great.’ ”

He returned to Organ Pipe the following summer to continue research on clumping behavior in the development process of saguaros, a study that he still works on today. The experience of following the growth of such hardy plants helped inspire his turtle research.

“One of the best ways to gain insights into the biology of long-lived organisms is to make a commitment to study them over a long period,” Janzen said. “So that’s part of my motivation.”

Janzen went on to attend Colorado State University to obtain a master’s in zoology, and began studying turtles. Then, he entered the University of Chicago as a doctoral student and was introduced to the emerging field of evolutionary genetics.

“That’s where I started working on some of the questions we still don’t have answers to,” Janzen said, “about the origins of sex-determining mechanisms. And why, in reptiles, they leave that question completely up to the environment. Why should an organism leave that up to whether the eggs are warm or cold? It’s remarkable.”

Hot chicks or cool dudes

Janzen explains that the selection of location for a turtle’s nest in either a sunny or shady spot will likely produce either all females or all males, respectively, or as he puts it, “hot chicks and cool dudes.”

To examine these mechanisms closer, while he was at Chicago he began a research project in 1988 along the Mississippi River, just north of Clinton, Iowa, that grew into what is now dubbed “Turtle Camp.” Tracking reptiles, particularly painted turtles, through the decades, the study continued while Janzen worked as a postdoctoral fellow at the University of California - Davis for two years and then when he arrived at Iowa State as an assistant professor in 1994.

“We have marked individuals that we recapture over and over,” Janzen said, “to gain an understanding of what they do and if they change over their lifetimes.”

The project, which originally started with Chicago undergraduate students assisting Janzen, picked up steam at Iowa State, with his undergraduate and graduate students making the trek to the study site for six weeks each summer. In 2004, Janzen opened the camp to interested high school students, many of whom are underrepresented minorities.

“I feel like we’ve been remarkably successful in getting these kids to go on to college,” Janzen said. “A big fraction, actually, are coming here (to ISU) … they’re either going on to be science teachers, or they’re involved in science as a career.”

Research brings turtles closer to home

As an expansion of the study closer to home, Janzen and his students are working at a site at the Horticulture Research Station near Ames to build four research ponds, one of which was completed this spring. The first pond is temporarily housing a group of around 50 adult turtles to produce a new generation. Janzen, along with his postdoctoral student, Dan Warner, has begun raising the new group of baby turtles in different environmental conditions.

“Literally, we are rearing them for their lifetimes, which could be decades,” Janzen said. “We’ve got them surrounded by electric fence to keep the raccoons out, and covered with shade cloth to minimize sun exposure and protect them from birds. We’ve learned so much about how to rear turtles in mass quantities.”

With the project reaching its 25th year, the team is beginning to see some of its original Mississippi River turtles nearing the end of their lives, which opens up a new possibility for them.

“We’re starting to learn about the complete reproductive lifetimes of these individuals,” Janzen said. “In other words, we’re going to start being able to answer questions about aging and senescence – whether turtles are highly fecund right up to the end, or if you see any slowdown.”

Seeing the unique values of his project and research, the National Science Foundation this month decided to continue funding Janzen for five more years with about $450,000. Janzen says the benefits to further studies, as well as to the university itself, merits the funding increase.

“I don’t know of anybody, anywhere in the country in our field, who involves as many students as we do annually in a meaningful way. They’re seriously doing real science,” Janzen said. “That, combined with the fact that the science we’re doing is published so often in top journals.”

Janzen sees his quarter-century of work with a single species, which he said places him in a “dying breed” of biologists, as helping lay an essential foundation for broader studies.

“We can answer big questions – we need to know theory, we need to understand concepts, no doubt – but, if we don’t know about the basic biology of certain organisms, we don’t know which organisms to use,” Janzen said. “And sometimes, we don’t even know which questions to ask.”

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