Conservation Research

Aquatic systems are complex and our understanding of how they function continues to evolve. Our research activities help inform our planning and restoration work to make sure that our efforts are consistent with the most current scientific knowledge of coldwater fisheries and their habitats.


Dauwalter, D.C., and J.D. Walrath. 2018. Beaver dams, streamflow complexity, and the distribution of a rare minnow, Lepidomeda copei. Ecology of Freshwater Fish 2018;27:606–616. This study shows how the distribution of a rare fish is driven by streamflow complexity, and that streamflow complexity is often higher in the presence of active and abandoned beaver dams.

Leasure, D.L., S.J. Wenger, N.D. Chelgren, H.M. Neville, D.C. Dauwalter, R. Bjork, K.A. Fesenmyer, J.B. Dunham, M.M. Peacock, C.H. Luce, A.C. Lute, D.J. Isaak. Hierarchical multi-population viability analysis. Ecology (in press). TU and University of Georgia have been extending the concept of Multiple Population Viability Analysis using a hierarchical Bayesian modelling framework.

Muhlfeld, C. C., D.C. Dauwalter, R.P. Kovach, J.L. Kershner, J.E. Williams, J. Epifanio. 2018. Trout in hot water: A call for global action. Science 360 (6391), 866-867. Trout are a culturally, economically, and ecologically important taxonomic group across the globe that require clean and cold water, and ¾ of them are threatened at some level from human stressors, including climate change.


Dauwalter, D.C., K.A. Fesenmyer, R. Bjork, D.R. Leasure, S.J. Wenger. 2017. Satellite and airborne remote sensing applications to freshwater fisheries. Fisheries 42(10):526-537 Remote sensing data is increasingly accessible, and this paper highlights the application of satellite and airborne data to freshwater fisheries applications.

Wenger, S.J., D.L. Leasure, D.C. Dauwalter, M.M. Peacock, J.D. Dunham, H.M. Neville, N. Chelgren. 2017. Viability analysis for multiple populations. Biological Conservation 216:69-77 TU and University of Georgia have developed new methods of population viability analysis to facilitate conservation planning and species recovery, and apply this new method to Lahontan cutthroat trout.


Neville, H., D. Dauwalter, and M. Peacock. 2016. Monitoring demographic and genetic responses of a threatened inland trout to habitat reconnection. Transactions of the American Fisheries Society 145:610-626. Describes results of a long-term study evaluating responses of Lahontan cutthroat trout to the reconnection of 3 streams to the mainstem Maggie Creek in Nevada, restoring one of the largest interconnected systems available to this threatened trout. Our monitoring results confirmed that the barrier remediation was successful in enabling movement among tributaries but uncovered complicated responses at the population level.

Walrath, J.D., D.C. Dauwalter, D. Reinke. 2016. Influence of stream condition on habitat diversity and fish assemblages in an impaired upper Snake River Basin watershed. Transactions of the American Fisheries Society 145:821-834. This study showed the linkage between habitat diversity and fish diversity in the Goose Creek subbasin on the Idaho, Utah, and Nevada border.


Dauwalter, D.C., K.A. Fesenmyer, R. Bjork. 2015. Using aerial imagery to characterize redband trout habitat in a remote desert landscape. Transactions of the American Fisheries Society 144:1322-1339. NAIP aerial imagery was used to characterize woody riparian vegetation in southwestern Idaho and northern Nevada, which was shown to be more predictive of redband trout distribution and abundance than field-based habitat measurements.

Splinter, D.K., R.C. Chester, D.C. Dauwalter. 2015. Trends and change points in Wisconsin’s streamflow. Sociological Imagination 51(2):69-95 This study was an evaluation of trends and change points in streamflows across Wisconsin.


Dauwalter, D.C., S.J. Wenger, P. Gardner. 2014. The role of complexity in habitat use and selection by stream fishes in a Snake River Basin tributary. Transactions of the American Fisheries Society 143(5):1177-1187 This study evaluated the small-scale habitat needs of a rare fish, the northern leatherside chub, in a tributary stream in south-central Idaho.

Neville, H.M. and D.P. Peterson. Genetic monitoring of trout movement after culvert remediation: family matters. 2014. Canadian Journal of Fisheries and Aquatic Sciences, 71: 1–15. We can learn a lot about movement and population dynamics by looking at how different families, and siblings within families, are distributed throughout stream networks


Al-Chokhachy, R., S.J. Wenger, D.J. Isaak and J.L. Kershner. 2013. Characterizing the thermal suitability of instream salmonids: a cautionary example from the Rocky Mountains. Transactions of the American Fisheries Society 142: 793-801. Not all methods of estimating trout temperature preferences yield the same results.

Dauwalter, D.C. 2013. Fish assemblage associations and thresholds with existing and projected oil and gas development. Fisheries Management and Ecology, 20:289-301.  This study explores how past and future oil and gas development in the upper Green River basin may impact riverine fish communities.

Goode, J.R., J.M. Buffington, D.J. Isaak, D. Tonina, R.F. Thurow, S.J. Wenger, D.E. Nagel, C.H. Luce, D. Tetzlaff and C. Soulsby. 2013. Understanding potential effects of climate change on streambed scour and risks to salmonid survival in mountain basins. Hydrologic Processes 27:750-765. This study explores how a changing climate could increase the frequency of high flows, mobilizing rocks and sand that could crush salmon and trout eggs.

Neville, H. M. and L. Bernatchez. 2013. Coding Gene Single Nucleotide Polymorphism Population Genetics of Nonnative Brook Trout: The Ghost of Introductions Past. Transactions of the American Fisheries Society 142:5, 1215-1231. This paper evaluates genetic diversity in different strains of brook trout introduced to Idaho over 100 years ago, and characterizes how this diversity translates to, and may have bolstered, patterns of genetic variation observed today in naturalized populations of non-native brook trout.

Peterson, E.E., J.M. Ver Hoef, D.J. Isaak, J. A. Falke, M.-J. Fortin, C.E. Jordan, K. McNyset, P. Monestiez, A.S. Ruesch, A. Sengupta, N. Som, E.A. Steel, D.M. Chokhachy, C.E. Torgersen, S.J. Wenger. 2013. Modelling dendritic ecological networks in space: an integrated network perspective. Ecology Letters 16: 707-719. We present more realistic approaches for modeling fish, temperature, and other stuff in stream networks.

Praggastis, A. and J.E. Williams. 2013. Salmon's Presence in Nevada's Past. Nevada Historical Society Quarterly. 56:14-32. While salmon once spawned in abundance in the headwater streams of northern Nevada, they are all but absent there today. We examine the causes of decline as well as strategies for recovery.

Wenger, S.J., N.A. Som, D.C. Dauwalter, D.J. Isaak, H.M. Neville, C.H. Luce, J.B. Dunham, M.K. Young, K.D. Fausch and B.E. Rieman. 2013. Probabilistic accounting of uncertainty in forecasts of species distributions under climate change. Global Change Biology, DOI: 10.1111/gcb.12294. We show how to incorporate uncertainty into predicting how species distributions may change in the future, using bull trout as an example.


Wenger, S.J., and J.D. Olden. 2012. Assessing transferability of ecological models: an underappreciated aspect of statistical validation. Methods in Ecology and Evolution. doi: 10.1111/j.2041-210X.2011.00170.x. Sometimes, ecological predictions aren’t as good as we think they are; we demonstrate a way to get more honest estimates of predictive ability.


Dauwalter, D. C., S. J. Wenger, K. R. Gelwicks, and K. A. Fesenmyer. 2011. Land use associations with declining native fishes in the Upper Colorado River Basin. Transactions of the American Fisheries Society 140:646-658.  Colorado River Basin fishes have declined, and this study explores how land uses may have played a role in the decline of some extant native fishes.

Neville, H.M., and J.B. Dunham. Patterns of Hybridization of Nonnative Cutthroat Trout and Hatchery Rainbow Trout with Native Redband Trout in the Boise River, Idaho. North American Journal of Fisheries Management 31:1163–1176. Hybridization with non-native species, including with hatchery rainbow trout originating from the Pacific coast, is one of the biggest threats to native redband trout; we found many populations in this high-visibility watershed were hybridized, but also uncovered a suite of unaltered populations that could be prioritized for conservation.

Wenger S.J., D.J. Isaak, J.B. Dunham, K.D. Fausch, C.H. Luce, H.M. Neville, B.E. Rieman, M.K. Young, D.E. Nagel, D.L. Horan, and G.L. Chandler. 2011. Role of climate and invasive species in structuring trout distributions in the interior Columbia River Basin, USA. Canadian Journal of Fisheries and Aquatic Sciences 68:988-1008. We study how native trout are affected by stream flows, stream temperature, and competition with introduced species.

Wenger S.J., D.J. Isaak, C.H. Luce, H.M. Neville, K.D. Fausch, J.B. Dunham, D.C. Dauwalter, M.K. Young, M.M. Elsner, B.E. Rieman, A.F. Hamlet, J.E. Williams. 2011. Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change. Proceedings of the National Academy of Sciences 108(34):14175–14180. In this large study, we assess how and why distributions of different trout species may change in the future.


Dauwalter, D.C., W.L. Fisher, F.J. Rahel. 2010. Warmwater streams. Pages 657 – 697 in Hubert, W.A. and M.C. Quist, editors. Inland Fisheries Management in North America, third edition. American Fisheries Society, Bethesda, Maryland. This book chapter, written by top scientists that have experience working in warmwater streams, describes how warmwater streams function and the types of approaches used to manage stream habitat and resident fish communities.

Wenger, S.J., C.H. Luce, A.F. Hamlet, D.J. Isaak and H.M. Neville. 2010. Macroscale hydrologic modeling of ecologically relevant flow metrics. Water Resources Research 46 (W09513): 10pp. doi:10.1029/2009WR008839. We estimate stream flows across the Northwestern US and examine how good these predictions are compared to real measurement.


Neville H, Dunham J, Rosenberger A, Umek J, Nelson B. 2009. Influences of wildfire, habitat size, and connectivity on trout in headwater streams revealed by patterns of genetic diversity. Transactions of the American Fisheries Society 138:1314-1327. Using genetic variability as a metric of population size and stability, we found that isolation by road culverts may pose greater threats to populations of native trout than wildfire and related disturbances.

Wenger, S.J., A.H. Roy, C.R. Jackson, E.S. Bernhardt, T.L. Carter, S. Filoso, C.A. Gibson, N.B. Grimm, W.C. Hession, S.S. Kaushal, E. Martí, J.L. Meyer, M.A. Palmer, M.J. Paul, A.H. Purcell, A. Ramirez, A.D. Rosemond, K.A. Schofield, T.R. Schueler, E. Sudduth, C.J. Walsh. 2009. Twenty-six key research questions in urban stream ecology: an assessment of the state of the science. Journal of the North American Benthological Society 28: 1080-1098. A large team of scientists identify the major future challenges in understanding urban streams.

Williams, J.E., A.L. Haak, H.M. Neville, and W.T. Colyer.  2009.  Potential consequences of climate change to persistence of cutthroat trout populations. North American Journal of Fisheries Management 29:533-548.  This report assesses broad-scale impacts of climate change to western trout populations and examines the increasing vulnerability to disturbances from wildfires, flooding, and drought. 

Williams, J.E., and J. Meka Carter.  2009.  Managing native trout past peak water. Southwest Hydrology 8(2):26-27, 34.  This report takes a close look at increasing drought in the Desert Southwest and impacts on Apache trout with potential management solutions.


Wenger, S.J. 2008. The use of surrogates to predict the stressor response of imperiled species. Conservation Biology 22:1564-15. It can be difficult to know how rare species will respond to stressors, such as urbanization and climate change; we show how to make a best guess based on the response of other species.

Wenger, S.J., T.L. Carter, R. A. Vick and L.A. Fowler. 2008. Runoff limits: an ecologically-based stormwater management program. Stormwater 9(2): 45-58. We propose a new program for managing stormwater to protect aquatic species.

Wenger, S.J. and M.C. Freeman. 2008. Estimating species occurrence, abundance and detecti


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