W. Carl Saunders

Job Title: Senior Research Scientist

Utah State University
Watershed Sciences Department
5210 Old Main Hill, NR 210
Logan UT 84322-5210

Office:  ECC 102
Email: carl.saunders@usu.edu

Staff Profile



Biological invasions in aquatic systems. I am interested in evaluating the effect of exotic species on the structure of aquatic communities and dynamics of fish populations. I am particularly interested in understanding environmental and biological factors limiting biological invasions that may be used to guide management efforts. I am also interested in understanding the population dynamics of invasive fishes, and developing tools to target regional hot spots (i.e., sources) of invasive fish. Finally, I am interested in understanding how global change and regional disturbance influence biological invasions.

Spatial structure of stream communities. I am interested in understanding the spatial arrangement of fish populations and the distribution of habitats across the landscape necessary to complete individual life history events. I am interested in how linear networks (i.e., rivers) are influenced by the 2-dimensional landscapes they are set within. Particularly, I am interested in understanding how fish populations are structured by dispersal, disturbance, and anthropogenic habitat alteration. I am interested in applying concepts of spatial statistics to aquatic communities to identify how variation in aquatic and terrestrial habitats influence aquatic communities with particular interest in understanding variation in demographic parameters and determining whether distinct aquatic populations have independent fates when disturbances occur throughout the terrestrial environment.

Population Dynamics of Fishes. I am interested in incorporating and evaluating recent advances in Mark-Recapture methodologies for fish to model demographic parameters and increase the accuracy with which we measure stream fish populations. I am interested in gaining better understanding about the frequency with which fish move throughout stream networks and the importance/cost of these movements. Furthermore, I am interested in applying population models to questions regarding the effects of disturbance on stream fish populations at a spatial scale that appropriate to draw inference about effects on movement, survival, and growth of individuals and ultimately population persistence. Finally, my interest in the quantitative ecology of stream fish is linked to my interest in food web ecology, as I am interested in developing a mechanistic understanding of how fish respond either demographically or via immigration/emigration to disturbances to stream food webs.

Reciprocal Subsidies between aquatic and terrestrial systems. I am interested in the factors controlling the flux of invertebrates between streams and riparian habitats and the importance of these subsidies as prey resources for consumer populations in recipient habitats. I am interested in how the structure and composition of streamside vegetation influences the vectors by which terrestrial invertebrates enter streams and how it influences the dispersal of aquatic insects away from the aquatic-terrestrial interface. My interests include the effects of land use on terrestrial-aquatic linkages and how the spatial structure of invertebrate subsidies influence consumer populations across the landscape.



Carl Saunders, is an aquatic ecologist researching factors that drive fish populations.  He joined the ET-AL at Utah State University in 2013, and works collaborative with Eco Logical Research, Inc.  Carl has 15 years of experience studying fish population across the western US, and has most recently completed a post-doctoral position at Utah State University.  Carl's post-doctoral research (conducted with Dr. Phaedra Budy of Utah State University's Watershed Sciences Department) focused on understanding the role of exotic species in water bodies of the western US and determining factors that limited success of exotic species in western rivers.  During this research, Carl evaluated the extent and timing of seasonal movement by burbot in Flaming Gorge Reservoir to evaluate potential impacts on sport fisheries and describe the spawning ecology of the rapidly expanding population in Flaming Gorge Reservoir and the Green River.  Additionally, Carl conducted laboratory and field experiments to evaluate the potential for high densities of native Bonneville cutthroat trout to limit success of exotic brown trout.  Carl completed a PhD in Aquatic Ecology at Colorado State University with Dr. Kurt Fausch.  Carl's dissertation focused on determining the effects of several systems for managing riparian cattle grazing on stream food webs and trout populations in the central and southern Rocky Mountains.   

  • Currently, Carl is working to integrate data on fish populations, fluvial structure, and water temperatures in the John Day Basin in Eastern Oregon to understand factors driving spatial variation in fish populations.

Scholarly Contributions

Peer Reviewed Publications

  • Saunders, W.C., and K.D. Fausch. 2012. Grazing management influences the subsidy of terrestrial prey to trout in central Rocky Mountain streams (USA). Freshwater Biology 57: 1512-1529.
  • Shannon L.W., C. Gowan, K.D. Fausch, J.G. Harris, and W.C. Saunders. 2011. Response of trout populations in five Colorado streams two decades after habitat manipulation. Canadian Journal of Fisheries and Aquatic Sciences 68: 2057-2063.
  • Saunders, W.C., K.D. Fausch, and G.C. White. 2011. Accurate Estimation of Salmonid Abundance Using Three-Pass Removal Electrofishing and Program MARK: an evaluation using marked fish. North American Journal of Fisheries Management 31: 403-415.
  • Saunders, W.C., and K.D. Fausch. 2007. Improved grazing management increases terrestrial invertebrate inputs that feed trout in Wyoming rangeland streams. Transactions of the American Fisheries Society 136(5): 1216-1230.
  • Baxter, C.V., K.D. Fausch, W.C. Saunders. 2005. Tangled webs: reciprocal flows of invertebrate prey link streams and riparian zones. Freshwater Biology 50: 201-220.

Conference Papers, Presentations & Posters

  • Oral presentation: Saunders, W.C., and P. Budy. 2012. Biotic resistance by native Bonneville cutthroat trout to the establishment of exotic brown trout is influenced by population density. American Fisheries Society, St. Paul, MN.
  • Oral presentation: Saunders, W.C., P. Budy, G. Thiede. 2011. Using Large-Scale Population Manipulation to Understand Source-Sink Dynamics of Invasive Brown Trout. AFS, Seattle, WA.
  • Oral presentation: Saunders, W.C., and K.D. Fausch. 2011. Effects of a Single Grazing Event by Cattle on Terrestrial Invertebrates Falling Into Streams and Trout Populations: Results of a Field Experiment. Society for Range Management, Billings, MT.