Ellen Wohl

Last name: 
GBC Committee Role: 

I did my BS and PhD degrees in geosciences at Arizona State University and the University of Arizona, respectively. I have been on the faculty at CSU since 1989. In addition to publishing in peer-reviewed journals, I enjoy writing for non-scientific audiences. Books thus far include Virtual Rivers (2001), Disconnected Rivers (2004), Island of Grass (2009), Of Rock and Rivers (2009), A World of Rivers (2011), Wide Rivers Crossed (2013), and Transient Landscapes (in press).

Professor of Geology
Research Interests (General): 
Research Interests (Specific): 
My research focuses on physical process and form in rivers, and how these interact with aquatic, riparian, and human communities. Much of my research is conducted on mountain rivers in the Colorado Front Range, but I have done field work on every continent but Antarctica. At present, my students and I are especially focusing on how instream wood, beavers, and channel-floodplain connectivity influence stream metabolism and organic carbon storage.
Research Projects: 
Project Title: 
Leaky Rivers: Nutrient Retention and Productivity in Rocky Mountain Streams Under Alternative Stable States
Project Location: 
United States
Project Location Details: 
Colorado and Wyoming, USA: Rocky Mountain National Park and Roosevelt and Medicine Bow National Forests
Study Species: 
Fish, Insect, Invertebrate
Project Description: 
Streams occupy a small part of Earth’s surface, but are disproportionately important for element transport and processing and for maintaining global biodiversity. Large wood strongly influences stream form and function, and channel-spanning structures such as logjams: 1) modify stream channel hydrology and geomorphology; 2) increase retention of sediment and organic matter; and 3) alter nutrient cycling. Logjams create biogeochemical hotspots in headwater streams, increasing stream metabolism and animal production. Human reductions in stream wood loads and logjams are pervasive in forested ecosystems around the world, creating “dam-impoverished” systems with limited capacity for organic matter storage and related ecosystem processes. A prime example is streams of the southern Rocky Mountains, where a legacy of wood removal has greatly reduced the size and along-stream frequency of jams.This project asks: Does the loss of jams reduce the productive capacity of headwater stream networks? and hypothesizes that the loss of jams makes streams more leaky of organic matter with subsequent decreased animal production, decreased in situ biogeochemical processing, and increased elemental export downstream. Our primary objectives are to: (i) quantify differences in logjams (along-stream spacing, size, hydraulic retention) on streams with different management histories, (ii) quantify biogeochemical processes (nutrient removal, storage and export, and ecosystem metabolism) and stream animal response (composition, secondary production) occurring in jams and in adjacent stream segments without jams, and (iii) examine the implications of reduced frequency of jams by scaling the site-specific measurements of biogeochemistry and stream animal response to entire watersheds. This will allow us to examine legacy effects on ecosystem processes by examining differences in logjams and jam-associated processes across a gradient of stream management, to link physical habitat to animal conservation and ecosystem function, and to provide the first landscape-scale assessment of the effects of jam removal on stream processes. Streams in and around Rocky Mountain National Park, Colorado drain large (>20 km2) patches of old-growth forests, unmanaged younger forests, and managed forests, providing a unique opportunity to compare characteristics of jams and their associated ecosystem functions in relation to forest age and management history.