Craig is a Research Ecologist at the Eastern Ecological Science Center in Kearneysville, WV.
Dr. Snyder is a Research Ecologist in the Aquatic Ecology Branch of the U.S. Geological Survey's (USGS) Leetown Science Center in Kearneysville, West Virginia. He holds a B.S. in Biology from Berry College (Georgia) and an M.S. and Ph.D. in Ecology from Virginia Tech University. Dr. Snyder's primary area of expertise is in the ecology of fish and aquatic macroinvertebrate communities inhabiting stream ecosystems in the Appalachian highlands. His Research emphasizes the role of natural landscape factors and their interaction with anthropogenic stressors in controlling the structure of stream communities. His investigations have included the effects of landscape disturbances such as urban land use and pest-induced changes in forest composition, acid rain and atmospheric deposition of mercury, and climate change. In addition, Dr. Snyder conducts research in support of long-term biological monitoring programs on federally-managed lands.
Science and Products
A hydrological framework to improve precision of Vital Signs metrics in the Appalachian highlands
Stream flow is a fundamental driver of ecological structure and function, but its influence on bioassessment measures is poorly understood. Although extreme flow conditions (e.g., floods and droughts) have long been known to play a central role in structuring stream communities, a mechanistic understanding of the linkages between flow variables, landscape and local physical characteristics, and...
USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature in Shenandoah National Park, Virginia
The U.S. Geological Survey (USGS) Water Mission Area (WMA) - Ecosystems Mission Area (EMA) EcoDrought project is comprised of interdisciplinary teams in five pilot regions across the country. The over-arching project goal is to measure streamflow in headwater streams and to relate flow variation to stream fish population dynamics. For the catchments located in Shenandoah National Park, Virginia,
USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature Data in Massachusetts
The USGS Water Mission Area (WMA) - Ecosystems Mission Area (EMA) EcoDrought project is comprised of interdisciplinary teams in five pilot regions across the country. The over-arching project goal is to measure streamflow in headwater streams and to relate flow variation to stream fish population dynamics. In the northeast, the New England Water Science Center (NewEngWSC) partnered with the fish
Stream temperature observations during summer 2021 for sites in the Sleepy Creek watershed, West Virginia
This Data Release contains stream temperature observations for 10 sites in the Sleepy Creek Watershed (West Virginia) during summer 2021. Data were collected using Onset ProV2 temperature gages within perforated PVC cases attached to stream substrates with rebar. Temperature gages were deployed and retrieved by volunteers with the Sleepy Creek Watershed Association. Temperature records are provide
Spatial patterns of dewatering within watersheds of Shenandoah National Park, Virginia 2016 - 2021 (ver. 2.0, December 2021)
These data describe longitudinal (upstream to downstream) patterns of dewatering during summer baseflow (July-September) conditions in nine watersheds in Shenandoah National park. In July-August of 2016 all nine watersheds (Jeremy's Run, Hazel River, Piney River, Hughes River, Staunton River, Whiteoak Canyon Run, Paine Run, Meadow Run, and Big Run) were evaluated for dewatering. In September of 20
Ambystomatid salamander population and breeding pond habitat data for the Delaware Water Gap National Recreation Area (2001 - 2003)
This database contains breeding pond use data (i.e., egg mass and larval abundance counts) of three ambystomatid salamander species (Spotted salamander, Jefferson salamander, and marbled salamander) collected from 200 individual aquatic habitats (ponds, wetlands, and impoundments) in the Delaware Water Gap National Recreation. Data were collected between the years 2001 and 2003. The database conta
Video data for trout abundance estimation
Rapid advances in video technology are enabling new strategies for species abundance estimation. Here we provide estimates of fish abundance derived from video data collected in a series of stream pools in Shenandoah National Park, Virginia (n=41). Two 360-degree cameras were simultaneously used at each pool site where 15-minutes of underwater footage was collected. Environmental data are provided
Benthic macroinvertebrates abundance data for the study of urbanization effects in the Delaware Water Gap National Recreation Area, (2006)
This database contains aquatic benthic macroinvertebrate abundance data derived from samples collected from 33 75-meter stream site locations within the Delaware Water Gap National Recreation area in September of 2006. The database contains two separate table files (i.e., entities) in csv format: 1) Macroinvertebrate site abundance data and 2) site location data. For macroinvertebrate data, six sa
Temperature data for study of shallow mountain bedrock limits seepage-based headwater climate refugia, Shenandoah National Park, Virginia
A combination of long-term daily temperature records and depth to bedrock measurements were used to parameterize one-dimensional models of shallow aquifer vertical heat transport in Shenandoah National Park, VA, USA. Spatially discontinuous roving water surface and bank temperatures surveys were performed with a handheld thermal infrared camera in September and December 2015 along the main channel
Air-water temperature data for the study of groundwater influence on stream thermal regimes in Shenandoah National Park, Virginia (ver. 2.0, May 3, 2018)
USGS Leetown Science Center scientists collected hourly air and water temperature data at 79 site locations within nine watersheds in Shenandoah National Park, Virginia over four water years (2012-2015). Data were collected using HOBO Pro V2 thermographs (accuracy = 0.2 degrees Celsius, drift = less than 0.1 degrees Celsius per year per year).
Filter Total Items: 21
Bedrock depth influences spatial patterns of summer baseflow, temperature and flow disconnection for mountainous headwater streams
In mountain headwater streams, the quality and resilience of summer cold-water habitat is generally regulated by stream discharge, longitudinal stream channel connectivity and groundwater exchange. These critical hydrologic processes are thought to be influenced by the stream corridor bedrock contact depth (sediment thickness), a parameter often inferred from sparse hillslope borehole information,
Authors
Martin Briggs, Phillip J. Goodling, Zachary Johnson, Karli M. Rogers, Nathaniel P. Hitt, Jennifer Burlingame Hoyle Fair, Craig D. Snyder
Managing nonperennial headwater streams in temperate forests of the United States
Forest management guidelines are designed to protect water quality from unintended effects of land use changes such as timber harvest, mining, or forest road construction. Although streams that periodically cease to flow (nonperennial) drain the majority of forested areas, these streams are not consistently included in forest management guidelines. This paper reviews management guidelines for nonp
Authors
Stephanie K. Kampf, Kathleen Dwyer, Matthew P. Fairchild, Jason B. Dunham, Craig D. Snyder, Kristin Jaeger, Charles H. Luce, John C. Hammond, Codie Wilson, Margaret Zimmer, Marielle Sidell
Heed the data gap: Guidelines for using incomplete datasets in annual stream temperature analyses
Stream temperature data are useful for deciphering watershed processes important for aquatic ecosystems. Accurately extracting signal trends from stream temperature is essential for predicting responses of environmental and ecological indicators to change. Missing data periods are common for various reasons, and pose a challenge for scientists using temperature signal analysis to support stream re
Authors
Zachary C. Johnson, Brittany G. Johnson, Martin A. Briggs, Craig D. Snyder, Nathaniel P. Hitt, Warren Devine
Assessment of Ambystomatid salamander populations and their breeding habitats in the Delaware Water Gap National Recreation Area
This report presents abundance and occurrence data for three species of ambystomad salamanders (Ambystoma maculatum, A. jeffersonianum, and A. opacum) collected over a 3-year period (2000, 2001, and 2002) at 200 potentional breeding sies within the Delaware Water Gap National Recreation Area (DEWA). In addition, numerous measures of inpond, near-pond, and landscape attributes were measured and use
Authors
Craig D. Snyder, John A. Young, James T. Julian, Tim L. King, Shanon E. Julian
Comparison of underwater video with electrofishing and dive‐counts for stream fish abundance estimation
Advances in video technology enable new strategies for stream fish research. We compared juvenile (age‐0) and adult (age 1+) Brook Trout Salvelinus fontinalis abundance estimates from underwater video with backpack electrofishing and dive‐count methods across a series of stream pools in Shenandoah National Park, Virginia (n = 41). Video methods estimated greater mean abundance of adult trout than
Authors
Nathaniel P. Hitt, Karli M Rogers, Craig D. Snyder, C. Andrew Dolloff
Paired air-water annual temperature patterns reveal hydrogeological controls on stream thermal regimes at watershed to continental scales
Despite decades of research into air and stream temperature dynamics, paired air-water annual temperature signals have been underutilized to characterize watershed processes. Annual stream temperature dynamics are useful in classifying fundamental thermal regimes and can enhance process-based interpretation of stream temperature controls, including deep and shallow groundwater discharge, when pair
Authors
Zachary C. Johnson, Brittany G. Johnson, Martin A. Briggs, Warren Devine, Craig D. Snyder, Nathaniel P. Hitt, D. Hare, T. Minkova
Identification of management thresholds of urban development in support of aquatic biodiversity conservation
Urbanization degrades stream ecosystems and causes loss of bodiversity. Using benthic macroinvertebrates as a surragate for overall aquatic diversity, we conducted a series of analytical approaches to derive management thresholds of urban development designed to link ecological responses to the primary management goal of protecting aquatic diversity in streams within the Delaware Water Gap Nationa
Authors
Craig D. Snyder, John A. Young
An integrated framework for ecological drought across riverscapes of North America
Climate change is increasing the severity and extent of extreme droughts events, posing a critical threat to freshwater ecosystems, particularly with increasing human demands for diminishing water supplies. Despite the importance of drought as a significant driver of ecological and evolutionary dynamics, current understanding of drought consequences for freshwater biodiversity is very limited. W
Authors
Ryan Kovach, Jason B. Dunham, Robert Al-Chokhachy, Craig Snyder, Erik A. Beever, Gregory T. Pederson, Abigail Lynch, Nathaniel P. Hitt, Christopher P. Konrad, Kristin Jaeger, Alan H. Rea, Adam J. Sepulveda, Patrick M. Lambert, Jason M. Stoker, J. Joseph Giersch, Clint C. Muhlfeld
Inferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals
Streams strongly influenced by groundwater discharge may serve as “climate refugia” for sensitive species in regions of increasingly marginal thermal conditions. The main goal of this study is to develop paired air and stream water annual temperature signal analysis techniques to elucidate the relative groundwater contribution to stream water and the effective groundwater flowpath depth. Groundwat
Authors
Martin A. Briggs, Zachary C. Johnson, Craig D. Snyder, Nathaniel P. Hitt, Barret L. Kurylyk, Laura K. Lautz, Dylan J. Irvine, Stephen T. Hurley, John W. Lane
Forecasting stream habitat and Brook Trout responses to climate change in Catoctin Mountain Park
Anticipating and mitigating the effects of climate change is a fundamental challenge for natural resource conservation. In this report, we respond to research needs identified by Catoctin Mountain Park (CATO) for native Brook Trout (Salvelinus fontinalis) conservation and management as part of the US Geological Survey (USGS) Natural Resources Preservation Program in FY15-16. We addressed three ove
Authors
Nathaniel P. Hitt, Craig D. Snyder, Erin Snook, Zachary Johnson, Matthew Morgan
Landform features and seasonal precipitation predict shallow groundwater influence on temperature in headwater streams
Headwater stream responses to climate change will depend in part on groundwater‐surface water exchanges. We used linear modeling techniques to partition likely effects of shallow groundwater seepage and air temperature on stream temperatures for 79 sites in nine focal watersheds using hourly air and water temperature measurements collected during summer months from 2012 to 2015 in Shenandoah Natio
Authors
Zachary C. Johnson, Craig D. Snyder, Nathaniel P. Hitt
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 seasonal
Authors
Martin A. Briggs, John W. Lane, Craig D. Snyder, Eric A. White, Zachary Johnson, David L. Nelms, Nathaniel P. Hitt
Science and Products
- Science
A hydrological framework to improve precision of Vital Signs metrics in the Appalachian highlands
Stream flow is a fundamental driver of ecological structure and function, but its influence on bioassessment measures is poorly understood. Although extreme flow conditions (e.g., floods and droughts) have long been known to play a central role in structuring stream communities, a mechanistic understanding of the linkages between flow variables, landscape and local physical characteristics, and... - Data
USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature in Shenandoah National Park, Virginia
The U.S. Geological Survey (USGS) Water Mission Area (WMA) - Ecosystems Mission Area (EMA) EcoDrought project is comprised of interdisciplinary teams in five pilot regions across the country. The over-arching project goal is to measure streamflow in headwater streams and to relate flow variation to stream fish population dynamics. For the catchments located in Shenandoah National Park, Virginia,USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature Data in Massachusetts
The USGS Water Mission Area (WMA) - Ecosystems Mission Area (EMA) EcoDrought project is comprised of interdisciplinary teams in five pilot regions across the country. The over-arching project goal is to measure streamflow in headwater streams and to relate flow variation to stream fish population dynamics. In the northeast, the New England Water Science Center (NewEngWSC) partnered with the fishStream temperature observations during summer 2021 for sites in the Sleepy Creek watershed, West Virginia
This Data Release contains stream temperature observations for 10 sites in the Sleepy Creek Watershed (West Virginia) during summer 2021. Data were collected using Onset ProV2 temperature gages within perforated PVC cases attached to stream substrates with rebar. Temperature gages were deployed and retrieved by volunteers with the Sleepy Creek Watershed Association. Temperature records are provideSpatial patterns of dewatering within watersheds of Shenandoah National Park, Virginia 2016 - 2021 (ver. 2.0, December 2021)
These data describe longitudinal (upstream to downstream) patterns of dewatering during summer baseflow (July-September) conditions in nine watersheds in Shenandoah National park. In July-August of 2016 all nine watersheds (Jeremy's Run, Hazel River, Piney River, Hughes River, Staunton River, Whiteoak Canyon Run, Paine Run, Meadow Run, and Big Run) were evaluated for dewatering. In September of 20Ambystomatid salamander population and breeding pond habitat data for the Delaware Water Gap National Recreation Area (2001 - 2003)
This database contains breeding pond use data (i.e., egg mass and larval abundance counts) of three ambystomatid salamander species (Spotted salamander, Jefferson salamander, and marbled salamander) collected from 200 individual aquatic habitats (ponds, wetlands, and impoundments) in the Delaware Water Gap National Recreation. Data were collected between the years 2001 and 2003. The database contaVideo data for trout abundance estimation
Rapid advances in video technology are enabling new strategies for species abundance estimation. Here we provide estimates of fish abundance derived from video data collected in a series of stream pools in Shenandoah National Park, Virginia (n=41). Two 360-degree cameras were simultaneously used at each pool site where 15-minutes of underwater footage was collected. Environmental data are providedBenthic macroinvertebrates abundance data for the study of urbanization effects in the Delaware Water Gap National Recreation Area, (2006)
This database contains aquatic benthic macroinvertebrate abundance data derived from samples collected from 33 75-meter stream site locations within the Delaware Water Gap National Recreation area in September of 2006. The database contains two separate table files (i.e., entities) in csv format: 1) Macroinvertebrate site abundance data and 2) site location data. For macroinvertebrate data, six saTemperature data for study of shallow mountain bedrock limits seepage-based headwater climate refugia, Shenandoah National Park, Virginia
A combination of long-term daily temperature records and depth to bedrock measurements were used to parameterize one-dimensional models of shallow aquifer vertical heat transport in Shenandoah National Park, VA, USA. Spatially discontinuous roving water surface and bank temperatures surveys were performed with a handheld thermal infrared camera in September and December 2015 along the main channelAir-water temperature data for the study of groundwater influence on stream thermal regimes in Shenandoah National Park, Virginia (ver. 2.0, May 3, 2018)
USGS Leetown Science Center scientists collected hourly air and water temperature data at 79 site locations within nine watersheds in Shenandoah National Park, Virginia over four water years (2012-2015). Data were collected using HOBO Pro V2 thermographs (accuracy = 0.2 degrees Celsius, drift = less than 0.1 degrees Celsius per year per year). - Publications
Filter Total Items: 21
Bedrock depth influences spatial patterns of summer baseflow, temperature and flow disconnection for mountainous headwater streams
In mountain headwater streams, the quality and resilience of summer cold-water habitat is generally regulated by stream discharge, longitudinal stream channel connectivity and groundwater exchange. These critical hydrologic processes are thought to be influenced by the stream corridor bedrock contact depth (sediment thickness), a parameter often inferred from sparse hillslope borehole information,AuthorsMartin Briggs, Phillip J. Goodling, Zachary Johnson, Karli M. Rogers, Nathaniel P. Hitt, Jennifer Burlingame Hoyle Fair, Craig D. SnyderManaging nonperennial headwater streams in temperate forests of the United States
Forest management guidelines are designed to protect water quality from unintended effects of land use changes such as timber harvest, mining, or forest road construction. Although streams that periodically cease to flow (nonperennial) drain the majority of forested areas, these streams are not consistently included in forest management guidelines. This paper reviews management guidelines for nonpAuthorsStephanie K. Kampf, Kathleen Dwyer, Matthew P. Fairchild, Jason B. Dunham, Craig D. Snyder, Kristin Jaeger, Charles H. Luce, John C. Hammond, Codie Wilson, Margaret Zimmer, Marielle SidellHeed the data gap: Guidelines for using incomplete datasets in annual stream temperature analyses
Stream temperature data are useful for deciphering watershed processes important for aquatic ecosystems. Accurately extracting signal trends from stream temperature is essential for predicting responses of environmental and ecological indicators to change. Missing data periods are common for various reasons, and pose a challenge for scientists using temperature signal analysis to support stream reAuthorsZachary C. Johnson, Brittany G. Johnson, Martin A. Briggs, Craig D. Snyder, Nathaniel P. Hitt, Warren DevineAssessment of Ambystomatid salamander populations and their breeding habitats in the Delaware Water Gap National Recreation Area
This report presents abundance and occurrence data for three species of ambystomad salamanders (Ambystoma maculatum, A. jeffersonianum, and A. opacum) collected over a 3-year period (2000, 2001, and 2002) at 200 potentional breeding sies within the Delaware Water Gap National Recreation Area (DEWA). In addition, numerous measures of inpond, near-pond, and landscape attributes were measured and useAuthorsCraig D. Snyder, John A. Young, James T. Julian, Tim L. King, Shanon E. JulianComparison of underwater video with electrofishing and dive‐counts for stream fish abundance estimation
Advances in video technology enable new strategies for stream fish research. We compared juvenile (age‐0) and adult (age 1+) Brook Trout Salvelinus fontinalis abundance estimates from underwater video with backpack electrofishing and dive‐count methods across a series of stream pools in Shenandoah National Park, Virginia (n = 41). Video methods estimated greater mean abundance of adult trout thanAuthorsNathaniel P. Hitt, Karli M Rogers, Craig D. Snyder, C. Andrew DolloffPaired air-water annual temperature patterns reveal hydrogeological controls on stream thermal regimes at watershed to continental scales
Despite decades of research into air and stream temperature dynamics, paired air-water annual temperature signals have been underutilized to characterize watershed processes. Annual stream temperature dynamics are useful in classifying fundamental thermal regimes and can enhance process-based interpretation of stream temperature controls, including deep and shallow groundwater discharge, when pairAuthorsZachary C. Johnson, Brittany G. Johnson, Martin A. Briggs, Warren Devine, Craig D. Snyder, Nathaniel P. Hitt, D. Hare, T. MinkovaIdentification of management thresholds of urban development in support of aquatic biodiversity conservation
Urbanization degrades stream ecosystems and causes loss of bodiversity. Using benthic macroinvertebrates as a surragate for overall aquatic diversity, we conducted a series of analytical approaches to derive management thresholds of urban development designed to link ecological responses to the primary management goal of protecting aquatic diversity in streams within the Delaware Water Gap NationaAuthorsCraig D. Snyder, John A. YoungAn integrated framework for ecological drought across riverscapes of North America
Climate change is increasing the severity and extent of extreme droughts events, posing a critical threat to freshwater ecosystems, particularly with increasing human demands for diminishing water supplies. Despite the importance of drought as a significant driver of ecological and evolutionary dynamics, current understanding of drought consequences for freshwater biodiversity is very limited. WAuthorsRyan Kovach, Jason B. Dunham, Robert Al-Chokhachy, Craig Snyder, Erik A. Beever, Gregory T. Pederson, Abigail Lynch, Nathaniel P. Hitt, Christopher P. Konrad, Kristin Jaeger, Alan H. Rea, Adam J. Sepulveda, Patrick M. Lambert, Jason M. Stoker, J. Joseph Giersch, Clint C. MuhlfeldInferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals
Streams strongly influenced by groundwater discharge may serve as “climate refugia” for sensitive species in regions of increasingly marginal thermal conditions. The main goal of this study is to develop paired air and stream water annual temperature signal analysis techniques to elucidate the relative groundwater contribution to stream water and the effective groundwater flowpath depth. GroundwatAuthorsMartin A. Briggs, Zachary C. Johnson, Craig D. Snyder, Nathaniel P. Hitt, Barret L. Kurylyk, Laura K. Lautz, Dylan J. Irvine, Stephen T. Hurley, John W. LaneForecasting stream habitat and Brook Trout responses to climate change in Catoctin Mountain Park
Anticipating and mitigating the effects of climate change is a fundamental challenge for natural resource conservation. In this report, we respond to research needs identified by Catoctin Mountain Park (CATO) for native Brook Trout (Salvelinus fontinalis) conservation and management as part of the US Geological Survey (USGS) Natural Resources Preservation Program in FY15-16. We addressed three oveAuthorsNathaniel P. Hitt, Craig D. Snyder, Erin Snook, Zachary Johnson, Matthew MorganLandform features and seasonal precipitation predict shallow groundwater influence on temperature in headwater streams
Headwater stream responses to climate change will depend in part on groundwater‐surface water exchanges. We used linear modeling techniques to partition likely effects of shallow groundwater seepage and air temperature on stream temperatures for 79 sites in nine focal watersheds using hourly air and water temperature measurements collected during summer months from 2012 to 2015 in Shenandoah NatioAuthorsZachary C. Johnson, Craig D. Snyder, Nathaniel P. HittShallow 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. Hitt - Multimedia
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