Chantal Iosso '20
Keck Advanced Research Project, Summer 2019
I participated in the Yellowstone Rivers Advanced Keck project with Dr. Lyman Persico of Whitman College, which was a five-week research experience in the Northern Range of Yellowstone. We camped out near the north and west entrances of Yellowstone for four weeks and did fluvial geomorphology field work on rivers on the Blacktail Deer plateau and the Gallatin River (the last week was spent organizing data and preparing samples). Many ecologists believe that trophic cascades caused by removal and then reintroduction of wolves to Yellowstone have been a major driver for ecosystem and river change. They suggest that wolves control elk numbers, and without wolves, elk overconsume willows, preventing beaver from building dams and leading to stream widening and incision. However, the longer history of Yellowstone and other factors like climate are not considered. Thus, we used a variety of techniques, including cross sections, bedload characterization, mapping, and analysis and dating of stratigraphy and beaver sediments to understand the long-term history of streams over the Holocene. My project is focused on using radiocarbon dating of charcoal and organic beaver pond sediments in paleochannels, cutbanks, slip-off terraces, and other geomorphic surfaces to understand the timing of aggradation, deposition, and beaver activity in the Northern Range of Yellowstone during the Holocene. I will compare these dates with climatic records and other factors, to help understand if wolves have really been a major driver of historic river change, or if climate drives the changes. I will continue working on this project during the school year as my environmental studies capstone.