Rainforest Stream Food Webs

Similar in vegetation types to the coastal temperate rainforests of the Pacific northwest, the inland temperate rainforest of Washington, British Columbia, Alberta, Idaho, and Montana is the only such rainforest in the world. This humid region is characterized by old-growth cedar and hemlock trees. I was fortunate to study fish in the streams of the inland temperate rainforest of Montana and British Columbia during my master’s program.

Quantitative stream food web in Bear Creek near Libby, MT

Didymosphenia geminata (Didymo) is a nuisance algae that can cover entire streambeds under certain environmental conditions, and is abundant in streams of the inland temperate rainforest. While relatively easy to treat, it is unknown whether Didymo decreases the amount of invertebrate prey for fishes. In the Kootenai River basin of Montana and British Columbia, I worked to determine if Didymo alters stream food webs and impacts native fishes such as Bull Trout, Redband Trout, and Slimy Sculpin. While Didymo did seem to impact invertebrate assemblages, it did not affect the diet, condition, or growth of native fishes.

Thermal-Optimum Bioenergetics (TOBE)

As part of my studies on native fish diets, I modified a technique for estimating the amount of food consumed by fishes to account for stream temperatures. This method may serve as a viable alternative to the considerably more complex bioenergetics models that are currently used. This method can even be easily adapted for any fish species without needing the species-specific laboratory tests required by bioenergetics (see Publications & Reports below).

Frequent Electrofishing & Trout Growth

Shocking Ramsey Creek near Libby, MT.

Sometimes we want to sample fish multiple times in a year to see how growth, condition, or diet changes over time. Very few studies have addressed how often fish can be captured and handled before there are negative effects on their growth. I am using data from my master’s work on Bear Creek to see if increased handling of trout led to decreased summer growth.

Publications & Reports

Clancy, N.G., J. Dunnigan, and P. Budy. In press. Relationship of trout growth to frequent electrofishing and diet collection in a headwater stream. North American Journal of Fisheries Management.

Clancy, N.G., J. Brahney, J. Dunnigan, and P. Budy. 2021. Effects of a diatom ecosystem engineer, Didymosphenia geminata, on stream food webs: implications for native fishes. Canadian Journal of Fisheries and Aquatic Sciences.

Clancy, N.G., J. Brahney, J. Curtis, and P. Budy. 2020. Consequences of Didymo blooms in the transnational Kootenay River basin. A report to BC Parks from the Department of Watershed Sciences at Utah State University, Logan, UT, USA.

Project Partners: Janice Brahney (Utah State University), Phaedra Budy (USGS/Utah State University), Jim Dunnigan (Montana Fish, Wildlife & Parks)
Project Funders: British Columbia Ministry of the Environment – BC Parks; U.S. Forest Service; Utah State University Dept of Watershed Sciences and Ecology Center
Acknowledgements: Jon McFarland, Ryan West, Marshall Wolf, Chris Clancy, Mike Young, Gary Thiede, Jay DeShazer, Ryan Sylvester, Chuck Hawkins, Jared Lampton, Jordan Frye, Brian Stephens, Monty Benner, Brett Roper, Mike Hensler, Jeff Burrows, Greg Andrusak, Joe Thorley, Murray Pearson.