From July 12th – August 2nd, I’ll be back in the field. I’m heading to Grand Teton National Park, to collect data that will help answer questions related to my dissertation research. My research focuses on the hierarchy of rock glacier relationships in the Greater Yellowstone Ecosystem, and specifically in Grand Teton National Park. Primarily, I’m concerned with how rock glaciers charge proximate water supplies and offer insights as to Earth’s changing climate.
First, I want to know more about rock glacier water supplies. Given that rock glaciers contain ice, it makes sense that some of the ice melts each season and drains down valley. In the case of the Cascade Canyon rock glacier, the meltwater drains into Jenny Lake and eventually charges the Snake River. But, how impactful is the relationship between rock glaciers in Grand Teton National Park and the Snake River? Do the park’s rock glacier have positive mass balances (meaning they trend toward growth) or negative mass balances (meaning they trend toward shrinkage)? Approximately what volume of water can be said to enter the area’s hydrology directly from rock glacier melt?
In the field, we’ll survey the Cascade Canyon Rock Glacier approximately 8 km inland from Jenny Lake. There, we’ll take ground GPS measurements of the rock glacier and verify it against aerial data back at the research station. Then, we’ll collect water samples from the rock glacier output stream, the terminal pond, up valley flow, proximate snowpack, proximate ponds, and down valley flow. If we get lucky enough to see rain, I’ll also grab precipitation samples. Then, I’ll send all collected samples off to the Reston Stable Isotope Lab for hydrogen and oxygen isotope analyses, which will help determine the source of each water sample. We’ll also gather data on the terminal pond through depth sounding, which might help us better understand how the pond formed and it’s potential hydrological contribution.
Secondly, I want to know about the flora and fauna that live in the Snake River Plain. Specifically, I’m interested in beavers as ecosystem engineers – animals that directly impact an area’s geomorphology through their behaviors. Of course, Earth’s changing climate affects environments on many scales. How sensitive might beavers be to environmental changes related to rock glacier meltwater? If rock glaciers contribute an abrupt output of meltwater in a given season, how might that affect beaver habitats? Similarly, how might beavers be affected if the water system did not receive meltwater inputs from rock glaciers at all? Are there things that we might be able to do through park management to help beavers transition through projected environmental change?
On our trip, we’ll gather data on beaver habitat variables at an identified field site within the park. (I visited the site in July and October of 2016 and composed a habitat map that we’ll rely on in the field.) For this portion, we’ll locate beaver dams, dens, bank burrows, and other attributes to better understand the potential of this site for beaver occupation. We’ll also gather data on river width, depth, velocity, and general characteristics to determine how small changes to the system (through rock glacier melt, perhaps) might affect beaver habitat. (For more information on beaver habitat variables, read my other post here.)
The data we collect over three weeks in the field will help me to do a few things. First, I want to refine a classification system for rock glaciers in the Tetons. With information on meltwater, I should be able to create a model that determines how much water we might expect one of the park’s rock glaciers to output into the hydrological system. Then, I hope to offer insight as to the role these meltwater reservoirs play in the overall system, especially as related to ecology. Finally, I hope to produce a habitat model for the Schwabacher Landing beavers, which might help mark management establish stricter protections for the high-traffic area.