Nathaniel (Than) Hitt, PhD
Dr. Nathaniel (Than) P. Hitt is a Research Fish Biologist at the USGS Eastern Ecological Science Center in Kearneysville, West Virginia
He holds a B.A. in Biology from the College of Wooster, an M.S. in Organismal Biology and Ecology from the University of Montana, and a Ph.D. in Fisheries and Wildlife Sciences from Virginia Tech. Dr. Hitt’s research investigates freshwater fish ecology from a landscape perspective, focusing on stream ecosystems in the Appalachian highlands. His research includes:
- Modeling fish habitat and population/community responses to environmental change
- Forecasting effects of climate change for fish habitat in headwater streams
- Effects of stream flow and temperature on fish population dynamics
- Optimizing conservation and restoration planning for native fishes
Professional Experience
2009-present: Research Fish Biologist, US Geological Survey, Eastern Ecological Science Center
2015-present: Adjunct Associate Professor, Department of Ecosystem Science and Management, Pennsylvania State University
2008-2009: Postdoctoral Researcher, US Geological Survey, Leetown Science Center
2007-2008: Postdoctoral Researcher, Virginia Tech, Department of Fisheries and Wildlife Sciences
2007-2008: Postdoctoral Researcher, Virginia Tech, Department of Fisheries and Wildlife Sciences
1999-2002: Graduate Research Assistant, University of Montana, Division of Biological Sciences
Education and Certifications
2007 PhD, Virginia Polytechnic Institute and State University, Blacksburg, VA, Department of Fisheries and Wildlife Sciences
2002 MS, University of Montana, Missoula, MT, Division of Biological Sciences, Organismal Biology and Ecology
1996 BA, The College of Wooster, Wooster, OH Biology, Honors
Science and Products
Shallow bedrock limits groundwater seepage-based headwater climate refugia
Brook trout use of thermal refugia and foraging habitat influenced by brown trout
Dermocystidium sp. infection in Blue Ridge Sculpin captured in Maryland
Threshold responses of Blackside Dace (Chrosomus cumberlandensis) and Kentucky Arrow Darter (Etheostoma spilotum) to stream conductivity
Seasonal temperature and precipitation regulate brook trout young-of-the-year abundance and population dynamics
Accounting for groundwater in stream fish thermal habitat responses to climate change
Seasonal weather patterns drive population vital rates and persistence in a stream fish
Threshold-dependent sample sizes for selenium assessment with stream fish tissue
Temporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining
Synthesis and interpretation of surface-water quality and aquatic biota data collected in Shenandoah National Park, Virginia, 1979-2009
Differential expression profiles of microRNA in the little brown bat (Myotis lucifugus) associated with white nose syndrome affected and unaffected individuals
Dam removal increases American eel abundance in distant headwater streams
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.
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Shallow bedrock limits groundwater seepage-based headwater climate refugia
Groundwater/surface-water exchanges in streams are inexorably linked to adjacent aquifer dynamics. As surface-water temperatures continue to increase with climate warming, refugia created by groundwater connectivity is expected to enable cold water fish species to survive. The shallow alluvial aquifers that source groundwater seepage to headwater streams, however, may also be sensitive to seasonalAuthorsMartin A. Briggs, John W. Lane, Craig D. Snyder, Eric A. White, Zachary Johnson, David L. Nelms, Nathaniel P. HittBrook trout use of thermal refugia and foraging habitat influenced by brown trout
The distribution of native brook trout (Salvelinus fontinalis) in eastern North America is often limited by temperature and introduced brown trout (Salmo trutta), the relative importance of which is poorly understood but critical for conservation and restoration planning. We evaluated effects of brown trout on brook trout behavior and habitat use in experimental streams across increasing temperatuAuthorsNathaniel P. Hitt, Erin Snook, Danielle L. MassieDermocystidium sp. infection in Blue Ridge Sculpin captured in Maryland
Raised pale cysts were observed on Blue Ridge Sculpin Cottus caeruleomentum during stream fish community surveys in Catoctin Mountain Park, Maryland. When examined histologically, preserved sculpin exhibited multiple cysts containing spherical endospores with a refractile central body characteristic of Dermocystidiumspp. Cysts were not observed on the gills or internally. The portion of the watersAuthorsVicki S. Blazer, Nathaniel P. Hitt, Craig D. Snyder, Erin Snook, Cynthia R. AdamsThreshold responses of Blackside Dace (Chrosomus cumberlandensis) and Kentucky Arrow Darter (Etheostoma spilotum) to stream conductivity
Chrosomus cumberlandensis (Blackside Dace [BSD]) and Etheostoma spilotum (Kentucky Arrow Darter [KAD]) are fish species of conservation concern due to their fragmented distributions, their low population sizes, and threats from anthropogenic stressors in the southeastern United States. We evaluated the relationship between fish abundance and stream conductivity, an index of environmental quality aAuthorsNathaniel P. Hitt, Michael Floyd, Michael Compton, Kenneth McDonaldSeasonal temperature and precipitation regulate brook trout young-of-the-year abundance and population dynamics
Abundance of the young‐of‐the‐year (YOY) fish can vary greatly among years and it may be driven by several key biological processes (i.e. adult spawning, egg survival and fry survival) that span several months. However, the relative influence of seasonal weather patterns on YOY abundance is poorly understood.We assessed the importance of seasonal air temperature (a surrogate for stream temperatureAuthorsYoichiro Kanno, Kasey C. Pregler, Nathaniel P. Hitt, Benjamin Letcher, Daniel Hocking, John E. B. WoffordAccounting for groundwater in stream fish thermal habitat responses to climate change
Forecasting climate change effects on aquatic fauna and their habitat requires an understanding of how water temperature responds to changing air temperature (i.e., thermal sensitivity). Previous efforts to forecast climate effects on brook trout habitat have generally assumed uniform air-water temperature relationships over large areas that cannot account for groundwater inputs and other processeAuthorsCraig D. Snyder, Nathaniel P. Hitt, John A. YoungSeasonal weather patterns drive population vital rates and persistence in a stream fish
Climate change affects seasonal weather patterns, but little is known about the relative importance of seasonal weather patterns on animal population vital rates. Even when such information exists, data are typically only available from intensive fieldwork (e.g., mark–recapture studies) at a limited spatial extent. Here, we investigated effects of seasonal air temperature and precipitation (fall,AuthorsYoichiro Kanno, Benjamin Letcher, Nathaniel P. Hitt, David A. Boughton, John E. B. Wofford, Elise ZipkinThreshold-dependent sample sizes for selenium assessment with stream fish tissue
Natural resource managers are developing assessments of selenium (Se) contamination in freshwater ecosystems based on fish tissue concentrations. We evaluated the effects of sample size (i.e., number of fish per site) on the probability of correctly detecting mean whole-body Se values above a range of potential management thresholds. We modeled Se concentrations as gamma distributions with shape aAuthorsNathaniel P. Hitt, David R. SmithTemporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining
Mountaintop mining (MTM) affects chemical, physical, and hydrological properties of receiving streams, but the long-term consequences for fish-assemblage structure and function are poorly understood. We sampled stream fish assemblages using electrofishing techniques in MTM exposure sites and reference sites within the Guyandotte River basin, USA, during 2010–2011. We calculated indices of taxonomiAuthorsNathaniel P. Hitt, Douglas B. ChambersSynthesis and interpretation of surface-water quality and aquatic biota data collected in Shenandoah National Park, Virginia, 1979-2009
Shenandoah National Park in northern and central Virginia protects 777 square kilometers of mountain terrain in the Blue Ridge physiographic province and more than 90 streams containing diverse aquatic biota. Park managers and visitors are interested in the water quality of park streams and its ability to support healthy coldwater communities and species, such as the native brook trout (SalvelinusAuthorsJohn D. Jastram, Craig D. Snyder, Nathaniel P. Hitt, Karen C. RiceDifferential expression profiles of microRNA in the little brown bat (Myotis lucifugus) associated with white nose syndrome affected and unaffected individuals
First documented in New York State in 2006, white nose syndrome (WNS) quickly became the leading cause of mortality in hibernating bat species in the United States. WNS is caused by a psychrophilic fungus, Geomyces destructans. Clinical signs of this pathogen are expressed as a dusty white fungus predominately around the nose and on the wings of affected bats. Relatively new biomarkers, such as miAuthorsD.D. Iwanowicz, L. R. Iwanowicz, N.P. Hitt, T.L. KingDam removal increases American eel abundance in distant headwater streams
American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwaterAuthorsNathaniel P. Hitt, Sheila Eyler, John E. B. WoffordNon-USGS Publications**
Hitt, N.P. and M. Hendryx. 2010. Ecological integrity of streams linked to human cancer mortality rates. EcoHealth 7:91-104.Hitt, N.P. and P.L. Angermeier. 2008. River-stream connectivity affects fish bioassessment performance. Environmental Management 42:132-150.Hitt, N.P. and P.L. Angermeier. 2008. Evidence for fish dispersal from spatial analysis of stream network topology. Journal of the North American Benthological Society 27:304-320.Hitt, N.P. and B.R. Murphy. 2007. An inquiry-based case study for conservation biology. Journal of Virginia Science Education 2:43-50.Hitt, N.P. and P.L. Angermeier. 2006. Effects of adjacent streams on local fish assemblage structure in western Virginia: implications for biomonitoring. American Fisheries Society Symposium 48:75-86.Vignieri, S.N., E.M. Hallerman, B.J. Bergstrom, D.J. Hafner, A.P. Martin, P. Devers, P. Grobler and N.P. Hitt. 2006. Mistaken view of taxonomy undermines conservation of an evolutionarily distinct mouse: a response to Ramey et al. Journal of Animal Conservation 9:237-243.Allendorf, F.W., R. Leary, N.P. Hitt, K. Knudsen, M. Boyer and P. Spruell. 2005. Cutthroat trout hybridization and the U.S. Endangered Species Act: one species, two policies. Conservation Biology 19:1326-1328.Hitt, N.P. and C.A. Frissell. 2004. A case study of surrogate species in aquatic conservation planning. Aquatic Conservation: Marine and Freshwater Ecosystems 14:625-633.Allendorf, F.W., R. Leary, N.P. Hitt, K. Knudsen, L. Lundquist, and P. Spruell. 2004. Intercrosses and the U.S. Endangered Species Act: should hybridized populations be included as westslope cutthroat trout? Conservation Biology 18: 1203-1213.Hitt, N.P., C.A. Frissell, C.C. Muhlfeld and F.W. Allendorf. 2003. Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and non-native rainbow trout, O. mykiss. Canadian Journal of Fisheries and Aquatic Sciences 60:1440-1451.Hitt, N.P. 2003. Immediate effects of wildfire on stream temperature. Journal of Freshwater Ecology 18:171-173.**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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