Colvin Winner Maddy Case ’12 Studies Impact of Gophers on Plant Communities in Oregon

Carol Peters ・ High Meadows Environmental Institute

In May 2011, Maddy Case ’12, an Ecology and Evolutionary Biology major earning a certificate in environmental studies, received the Becky Colvin Memorial Award from PEI. The award was established in 1995 by Dr. and Mrs. Robert Colvin in memory of their daughter, Becky Colvin ’95. Becky was an ecology and evolutionary biology major who was very interested in field research. The annual fund supports summer environmental field research projects following the junior year, in support of the senior thesis. Last summer Maddy conducted research for her senior thesis in Oregon. Below, PEI speaks to Maddy about how the Colvin award made her research possible, her plans following graduation, and advice for this summer’s recipient.

Maddy Case ‘12

Please describe your project, the goals of your senior thesis, and how the Colvin award supported your work.

gohper trails
Gopher castings, which are raised tubes of dirt left behind from the tunnels that gophers dig through the snow and backfill with excavated soil. (Photos: Maddy Case)

My working thesis title is “Gopher Disturbance and Plant Community Dynamics in Montane Meadows.”

I studied how gopher disturbance affects plant community dynamics in montane meadows in Oregon’s Cascade Range. In the meadows where I studied, gophers have a huge impact on their physical environment by creating mounds of excavated soil, which bury the existing vegetation and provide bare ground where new plants can establish. I’m interested in how such disturbance can affect important characteristics of meadow plant communities like diversity and spatial heterogeneity. I’m studying this by analyzing field data I collected as well as creating a theoretical simulation model of how gophers can facilitate coexistence of different types of plants. With the generous funding provided by the Colvin Award, I spent last summer living at the H.J. Andrews Experimental Forest in Oregon. I was accompanied by Sarah Koe, a high school student, who volunteered as my field assistant. We worked together collecting data at a beautiful site called Bunchgrass Ridge.

Why did you choose this research location in Oregon?

I wanted to do research close to home (my family lives in Beaverton, Oregon, about a three-hour drive from where I did my research) and I had wanted to live and work at the H.J. Andrews Forest since I read a book about the place when I was 15. When I first started thinking about planning my senior thesis work, I checked out the website for the Andrews and came across information about Bunchgrass Ridge, which sounded like a fascinating study site. I was interested in plant ecology, but I had never worked in a grassland system before and I thought it might be interesting. I got in touch with Charlie Halpern, professor at the University of Washington, and asked him about potential projects. I ended up deciding that the gophers sounded really interesting. It was a topic that would allow me to address big questions in plant ecology with fieldwork and theoretical approaches, and Bunchgrass seemed to be a great place for it!

How did you find your research assistant, where did she go to high school, and how did she assist you?

Maddy Case
Sarah Koe with her chair and umbrella. Once she realized she would be sitting in a meadow for hours on end all summer, she brought out her family’s giant beach umbrella and a camp chair with a footrest to make her job comfortable!

Sarah is currently a senior at Catlin Gabel, the high school in Portland, Oregon where I attended. When I was starting to plan my field work, I realized it would be safer, and immensely helpful, to have a field assistant. It occurred to me that volunteering with a project like this was something I would have loved to do as a high school student. I contacted all of my former science teachers from high school, asking whether they had any students who were excited about ecology, comfortable in the outdoors, and potentially interested in helping me. One teacher put me in touch with Sarah. I was instantly impressed by her enthusiasm about the project, and she ended up being the best assistant I could have asked for! She helped me set up the transects and record all the data I called out while I was kneeling on the ground taking measurements. This meant that I could go a lot faster. Without Sarah’s help I wouldn’t have been able to collect as much data as I did, and I also might have gone crazy from working alone in the meadows all summer. She also learned a lot from the experience and had a great time hanging out with field biologists at the Andrews all summer, so it was really mutually beneficial. I was very grateful that the Colvin award made this possible by covering her living expenses.

Why is your research important, and do you hope it will have an impact beyond the campus?

Disturbance is a crucial factor in shaping natural communities. I hope my research will shed light on the relationship between disturbance and diversity. My research will also help us to better understand how grassland communities function and how certain organisms, such as gophers, can play pivotal roles in determining which plants can live where.

Were you able to accomplish what you originally intended, or did the parameters of the project change once you began?

I intended to do an experiment in which I would create my own gopher mounds using soil from fresh mounds, which would have allowed me to compare the abilities of different plant species to recover from burial. The snow in the meadows melted unusually late last spring. This meant the growing season was shorter than I anticipated and the timing for such an experiment probably wasn’t going to work out. Consequently, when I first arrived at my field site I ended up having to switch to an observational study and develop a new study design on the spot.

What surprised you the most about your results or experience?

Not only was the late snowmelt a surprise, but so was the abundance of gopher castings snaking across the ground surface. These castings are raised tubes of dirt left behind from the tunnels that gophers dig through the snow and backfill with excavated soil. I hadn’t even read about the castings before, since most of the places where gophers have been studied don’t have such a deep, long-lasting snowpack. As it turns out, castings cover about the same amount of ground surface as gopher mounds do, making them a substantial form of gopher disturbance that I took into account in my data collection.

What were the most important lessons you learned during the course of this project?

I learned a lot about revising a research plan in response to unexpected conditions, and about how to make methodological decisions I could justify to myself and to other scientists. This is the biggest project I’ve ever worked on, and I think I’ve gained a lot of maturity in learning how to pace myself and to work through the day-to-day frustrations while staying focused on the fascinating ecological questions that got me interested in this project in the first place.

Will this project impact your career plans after graduation? If so, how?

I’m headed to Asia next year as part of the Luce Scholars Program, where I will work in the field of ecology and conservation. Then I’m planning to apply to Ph.D. programs in ecology. While I can’t say whether gophers will come up again in my career, this project has been incredibly valuable for me in affirming my interest in plant ecology and teaching me what it takes to carry out a self-directed research project. I’ve also been lucky enough to work with two incredible mentors for this project (Professor Simon Levin here at Princeton, and Professor Charles Halpern at the University of Washington). I have learned a lot from their examples, which will certainly guide my career as a scientist.

What advice would you give the next Colvin winner?

Field research is unpredictable. It is entirely likely that none of the methods you carefully lay out in your junior paper will actually work in the field. The best you can do is to learn as much as you can about your study system before you get out there, make a flexible plan, and be prepared to improvise!

This is one of two articles covering PEI’s 2011 Colvin Award winners. In addition to Maddy Case, geosciences major Sara Nason ’12 was also awarded Colvin funds last spring. Both students will graduate with certificates in environmental studies. Nason’s research will be featured in May.