Joshua Rose GDPE master thesis defense
Thursday, May 17, 2012, 01:00 PM
Forestry Building, Room 217

Cottonwood (Populus spp.) trees form the principle riparian forest type in the semi-arid western United States and provide essential habitat to avian and terrestrial wildlife. In Yellowstone National Park the presence of two ungulate species provided the opportunity to study how hydrology and herbivory interact to shape the structure and function of cottonwood forests.

My thesis research quantifies the influence of stream hydrologic regime and herbivory on cottonwood establishment and growth along three rivers in Yellowstone’s northern range. I developed a baseline dataset of mature and sapling stand characteristics and distribution, reconstructed establishment events over the 20th century, and quantified the relative importance of hydrology and herbivory with respect to establishment.I quantified herbivory by elk and bison on cottonwood during 2007 and 2008 and modeled herbivory at multiple consumption rates.

The results of my research show that establishment of cottonwood is driven by hydrologic processes, the distribution of cottonwood in Yellowstone has changed little over the past century, and low consumption rates have significant impacts on cottonwoods.

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Event Contact: Jeri Morgan can be reached at (970) 491-4373

Sponsored by the Graduate Degree Program in Ecology.