Q&A: Bio Student Researches Alpine Environment in Yosemite

Brooke Wallasch (blue shirt), a Cal Poly master’s student in biological sciences, has conducted research to study how climate conditions may be impacting alpine plants. She worked with biological sciences Professor Dena Grossenbacher (far right) on the research. 

September 2025 / NEWS STORY
by Anna Frias

Calling it an “incredible opportunity,” Cal Poly biological sciences student Brooke Wallasch has developed her skills and interests in the natural world through long-term plant-related research in a spectacular setting — the mountains of Yosemite National Park.

Wallasch earned her bachelor’s degree in Cal Poly in biological sciences in June 2024, and continuing her studies, now is nearing the completion of her master’s degree education at Cal Poly with a passion for botany and alpine environments.

She strengthened her research knowledge and skills by spending summers backpacking to alpine vegetation monitoring plots in Yosemite as part of ongoing work to better understand climate-related impacts to the habitat.

Wallasch soon will start a Ph.D. program at UC Riverside. She reflected on the impact of her Cal Poly master’s thesis and the future management of alpine vegetation in Yosemite.

Q: What research project did you work on this summer?

A: I’m currently finishing up my master’s thesis studying alpine plants and climate change in Yosemite National Park. I have three wonderful undergraduate field assistants through the Frost program — Annalise Burrows, Madeleine Colbert and Michael Gottlieb — whom I trained in the field protocols, plant identification and backcountry safety during spring quarter.

We volunteered with a nonprofit organization called GLORIA Great Basin, surveying existing alpine vegetation monitoring plots in the White Mountains of California during the first week of the field season. GLORIA is a global network of observational research in alpine environments that has several target regions in North America.

During the next two weeks of the field season, we backpacked in Yosemite National Park to establish and survey 10 100-meter transects (a transect is a line or strip used as a path to study the distribution and abundance of the plants) on the southwest slope of Mount Gibbs following the GLORIA downslope protocol.

Transect lines (in yellow) are set up to measure
plant data within designated areas.

After we hiked in and set up a base camp, each day involved hiking up the side of Mount Gibbs, using a high-accuracy GPS unit to locate the center point of each transect, and laying out the transect tape along the corresponding contour line.

Each transect is at a specific elevation and the transects are 25 vertical meters apart from one another. Then, the transects are split into 5-meter segments, and we essentially look within each 1-meter by 5-meter segment and identify all the plant species that are growing in that area. This process requires a lot of attention to detail and can be very time-consuming and tiring, especially after spending time hiking all the way up to the study site.

Q: What is the purpose of this research project?

A: The purpose of this project is two-fold. The first objective is to set up new monitoring plots in Yosemite to track changes in alpine plant communities over time with climate change. As temperatures warm, thermoclines (bands of like temperatures) are expected to shift upslope.

Alpine plants are expected to shift upslope to chase cooler temperatures. We have already established transects on three other peaks (Mount Dana, Mount Lewis, Gaylor Lakes) over the past two years. This project started with previous master’s student Rachel Friesen. Since our transects are at multiple elevation bands along the slope, if we survey approximately every five years, we will be able to see if and how plant communities change over time. For example, we would expect plants currently growing in lower transects to be growing in higher transects in future surveys.

The second purpose of this project is to offer undergraduate students opportunities to have hands-on field work experience, hone their field identification skills, and network with botanists from different walks of life, including faculty from other institutions, organizations (GLORIA Great Basin) and careers (National Park Service, U.S. Forest Service).

I had the incredible opportunity to be on Rachel Friesen’s crew for two years before taking over last summer and the experiences I had on her crew truly changed my life. The experiences from those field seasons gave me the skills I needed to continue on to do my master’s at Cal Poly, and also to study alpine plants by pursuing a Ph.D. at UC Riverside in the fall.

Q: What professor are you working with and how has that person helped guide you?

A: I am working with biological sciences Professor Dena Grossenbacher. Dr. Grossenbacher is an incredible mentor and has trained me throughout the scientific process, from designing a research project to collecting data and writing up my senior project and thesis. She has been incredibly supportive and has connected me with many other mentors in my field of research. She truly goes above and beyond for her students and trains soon-to-be ecologists in the real world, which includes project management, data collection, statistical analysis and scientific writing.

I am so thankful she took me under her wing while I was an undergraduate and wouldn't be where I am today without her. I’m also thankful to Dr. Phil Bailey (Bailey College dean emeritus and director of the Fund Fund), who encouraged me to pursue grad school while I was in the Frost Scholars program.

Q. What is most exciting about this research?

A: The most exciting thing about my research is being part of a forward-thinking project that is collecting data that will inform future management of alpine vegetation in Yosemite. I am thankful for Dr. Grossenbacher, Rachel Friesen and the folks at GLORIA Great Basin for helping get this project off the ground. As Mark Twain once said, “The secret to getting ahead is getting started,” and this project is a perfect example of that. It can be a little anticlimactic setting up new monitoring plots, as we won’t be able to see any change over time until the future surveys are completed in five years. But the only way to track that change over time is by setting up these transects now. It’s a very nice lesson in patience.

 

Mount Gibbs in Yosemite is one of the sites where Brooke Wallasch and her research team established transects.