Christian E Torgersen
I am a Supervisory Research Wildlife Biologist at the Forest and Rangeland Ecosystem Science Center
My research interests include landscape ecology, riverine landscapes, watershed processes, ecological scaling, water quality, fish habitat, land use/land cover change, landscape scenario modeling, spatial analysis, remote sensing and GIS.
Professional Experience
2002 - Present: USGS Forest and Rangeland Ecosystem Science Center, Supervisory Research Wildlife Biologist, Seattle, WA
Education and Certifications
Ph.D., Fisheries Science, Oregon State University, Corvallis, OR (2002)
M.S., Fisheries Science, Geography Minor, Oregon State University, Corvallis, OR (1996)
B.A., Geography/German, double major, University of Oregon, Eugene, OR (1993)
Science and Products
Aquatic & Landscape Ecology Research Team (FRESC)
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Hydrological connectivity for riverine fish: measurement challenges and research opportunities
Predicting recolonization patterns and interactions between potamodromous and anadromous salmonids in response to dam removal in the Elwha River, Washington State, USA
Longitudinal patterns of fish assemblages, aquatic habitat, and water temperature in the Lower Crooked River, Oregon
A spatially explicit approach for evaluating relationships among coastal cutthroat trout, habitat, and disturbance in small Oregon streams
A geostatistical approach for describing spatial pattern in stream networks
Evaluating single-pass catch as a tool for identifying spatial pattern in fish distribution
Influence of habitat heterogeneity on the distribution of larval Pacific lamprey (Lampetra tridentata) at two spatial scales
Pattern detection in stream networks: Quantifying spatial variability in fish distribution
Comment: "Perspectives on water flow and the interpretations of FLIR images" J.Range Manage. 55: 106-111 2002
Landscapes to riverscapes: bridging the gap between research and conservation of stream fishes
Multiscale thermal refugia and stream habitat associations of chinook salmon in northwestern Oregon
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
To request an interview, contact fresc_outreach@usgs.gov or call (541) 750-1030.
Science and Products
- Science
Aquatic & Landscape Ecology Research Team (FRESC)
Fresh waters are one of the most valuable and threatened resources worldwide. They supply critical services to society and harbor many of the world’s most imperiled species. We conduct research and provide technical assistance to address challenges to fresh waters. Our research focuses on ecological processes in freshwater and terrestrial systems and the effects of those processes on landscape... - Data
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
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- Publications
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Filter Total Items: 59Hydrological connectivity for riverine fish: measurement challenges and research opportunities
In this review, we first summarize how hydrologic connectivity has been studied for riverine fish capable of moving long distances, and then identify research opportunities that have clear conservation significance. Migratory species, such as anadromous salmonids, are good model organisms for understanding ecological connectivity in rivers because the spatial scale over which movements occur amongAuthorsA.H. Fullerton, K.M. Burnett, E.A. Steel, R.L. Flitcroft, G.R. Pess, B.E. Feist, Christian E. Torgersen, D. J. Miller, B.L. SandersonPredicting recolonization patterns and interactions between potamodromous and anadromous salmonids in response to dam removal in the Elwha River, Washington State, USA
The restoration of salmonids in the Elwha River following dam removal will cause interactions between anadromous and potamodromous forms as recolonization occurs in upstream and downstream directions. Anadromous salmonids are expected to recolonize historic habitats, and rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) isolated above the dams for 90 years are expected toAuthorsS.J. Brenkman, G.R. Pess, C.E. Torgersen, K.K. Kloehn, J.J. Duda, S.C. CorbettLongitudinal patterns of fish assemblages, aquatic habitat, and water temperature in the Lower Crooked River, Oregon
The Lower Crooked River is a remarkable groundwater-fed stream flowing through vertical basalt canyons in the Deschutes River Valley ecoregion in central Oregon (Pater and others, 1998). The 9-mile section of the river between the Crooked River National Grasslands boundary near Ogden Wayside and river mile (RM) 8 is protected under the National Wild and Scenic Rivers Act (16 U.S.C. 1271-1287) forAuthorsChristian E. Torgersen, David P. Hockman-Wert, Douglas S. Bateman, David W. Leer, Robert E. GresswellA spatially explicit approach for evaluating relationships among coastal cutthroat trout, habitat, and disturbance in small Oregon streams
Abstract has not been submittedAuthorsR. E. Gresswell, C.E. Torgersen, D.S. Bateman, T.J. Guy, S.R. Hendricks, J. E. B. WoffordA geostatistical approach for describing spatial pattern in stream networks
The shape and configuration of branched networks influence ecological patterns and processes. Recent investigations of network influences in riverine ecology stress the need to quantify spatial structure not only in a two-dimensional plane, but also in networks. An initial step in understanding data from stream networks is discerning non-random patterns along the network. On the other hand, data cAuthorsL.M. Ganio, C.E. Torgersen, R. E. GresswellEvaluating single-pass catch as a tool for identifying spatial pattern in fish distribution
We evaluate the efficacy of single-pass electrofishing without blocknets as a tool for collecting spatially continuous fish distribution data in headwater streams. We compare spatial patterns in abundance, sampling effort, and length-frequency distributions from single-pass sampling of coastal cutthroat trout (Oncorhynchus clarki clarki) to data obtained from a more precise multiple-pass removal eAuthorsDouglas S. Bateman, Robert E. Gresswell, Christian E. TorgersenInfluence of habitat heterogeneity on the distribution of larval Pacific lamprey (Lampetra tridentata) at two spatial scales
1. Spatial patterns in channel morphology and substratum composition at small (1–10 metres) and large scales (1–10 kilometres) were analysed to determine the influence of habitat heterogeneity on the distribution and abundance of larval lamprey.2. We used a nested sampling design and multiple logistic regression to evaluate spatial heterogeneity in the abundance of larval Pacific lamprey, LampetraAuthorsChristian E. Torgersen, David A. ClosePattern detection in stream networks: Quantifying spatial variability in fish distribution
Biological and physical properties of rivers and streams are inherently difficult to sample and visualize at the resolution and extent necessary to detect fine-scale distributional patterns over large areas. Satellite imagery and broad-scale fish survey methods are effective for quantifying spatial variability in biological and physical variables over a range of scales in marine environments but aAuthorsChristian E. Torgersen, Robert E. Gresswell, Douglas S. BatemanComment: "Perspectives on water flow and the interpretations of FLIR images" J.Range Manage. 55: 106-111 2002
No abstract available.AuthorsR. L. Beschta, B.A. McIntosh, Christian E. TorgersenLandscapes to riverscapes: bridging the gap between research and conservation of stream fishes
Rivers and streams, by their very nature long ribbons of aquatic habitat, are inherently difficult to study. Approaching the banks of a flowing-water (lotic) system, one can see only a short fragment of the entire stream, from one bend to another, and can gain little appreciation for important features that lie beyond view. Moreover, materials transported downstream by the flow, and organisms travAuthorsKurt D. Fausch, Christian E. Torgersen, Colden V. Baxter, Hiram W. LiMultiscale thermal refugia and stream habitat associations of chinook salmon in northwestern Oregon
We quantified distribution and behavior of adult spring chinook salmon (Oncorhynchus tshawytscha) related to patterns of stream temperature and physical habitat at channel-unit, reach-, and section-level spatial scales in a wilderness stream and a disturbed stream in the John Day River basin in northeastern Oregon. We investigated the effectiveness of thermal remote sensing for analyzing spatial pAuthorsChristian E. Torgersen, David M. Price, Hiram W. Li, B.A. McIntoshNon-USGS Publications**
Torgersen, C.E., Close, D.A., 2004, Influence of habitat heterogeneity on the distribution of larval Pacific lamprey (Lampetra tridentata) at two spatial scales: Freshwater Biology, v. 49, no. 5, p. 614-630.Fausch, K.D., Torgersen, C.E., Baxter, C.V., Li, H.W., 2002, Landscapes to riverscapes- bridging the gap between research and conservation of stream fishes: BioScience, v. 52, no. 6, p. 483-498.Torgersen, C.E., Faux, R.N., McIntosh, B.A., Poage, N., Norton, D.J., 2001, Airborne thermal remote sensing for water temperature assessment in rivers and streams: Remote Sensing of Environment, v. 76, p. 386-398.Torgersen, C.E., Price, D.M., Li, H.W., McIntosh, B.A., 1999, Multiscale thermal refugia and stream habitat associations of chinook salmon in northwestern Oregon: Ecological Applications, v. 9, no. 1, p. 301-319, https://doi.org/10.1890/1051-0761(1999)009[0301:MTRASH]2.0.CO;2.Torgersen, C.E., Poage, N., Flood, M., Norton, D.J., McIntosh, B.A., 1996, Airborne thermal remote sensing of salmonid habitat for restoration planning in Pacific Northwestern watersheds, Baltimore, MD In eds., Proceedings of the Watershed 96 Conference: Alexandria, VA, Water Environment Federation, p. 812-814.Poage, N., Torgersen, C.E., Norton, D.J., Flood, M., McIntosh, B.A., 1996, Application of thermal infrared (FLIR) and visible videography to the monitoring and restoration of salmonid habitat in the Pacific Northwest In Greer, J.D., ed., Proceedings of the Sixth Forest Service Remote Sensing Applications Conference: Denver, CO, American Society for Photogrammetry and Remote Sensing, p. 376-379.Torgersen, C.E., Jones, J.A., Moldenke, A.R., LeMaster, M.P., 1995, The spatial heterogeneity of soil invertebrates and edaphic properties in an old growth forest stand in western Oregon In Collins, H.P., Robertson, G.P., Klug, M.J., eds., The Significance and Regulation of Soil Biodiversity: Dordrecht, Netherlands, Kluwer Academic Publishers, p. 225-236.Torgersen, C.E., Price, D.M., Li, H.W., McIntosh, B.A., 1995, Thermal refugia and chinook salmon habitat in Oregon- Applications of airborne thermal videography In Mausel, P., ed., Proceedings of the 15th Biennial Workshop on Color Photography and Videography: Terre Haute, IN, American Society for Photogrammetry and Remote Sensing, p. 167-171.Torgersen, C.E., Baxter, C.V., Li, H., McIntosh, B.A., 2006, Landscape influences on longitudinal patterns of river fishes- Spatially continuous analysis of fish-habitat relationships In Hughes, R., Wang, L., Wofford, J.E., eds., Influences of Landscapes on Stream Habitats and Biological Assemblages: Bethesda, MD, American Fisheries Society, p. 473-492**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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To request an interview, contact fresc_outreach@usgs.gov or call (541) 750-1030.