Daniel L Calhoun
Biography
Dan’s unofficial career with the USGS began in 1995 when he was “volunteered” to help USGS Hydrologic Technicians dig orifice lines and haul materials for new gage installations along Ichawaynochaway Creek in Southwest Georgia. He was working as a Hydrologic Technician for the Jones Ecological Research Center and had no idea what a couple days of Coastal Plain Georgia sweat would later bring. It was through this encounter that he was given an invitation to apply for an open student position (STEP in those days) with the USGS after he had started graduate studies in Water Resources at the University of Georgia in 1998. Upon completion of his degree, Dan converted to a Hydrologist position working with the Appalachicola-Chattahoochee-Flint Study Unit (ACFB) of the National Water Quality Assessment Program. Twenty plus years of employment have involved participation in and direction of multiple national and regional watershed and groundwater projects, amphibian research in the Southeast, liaison duties with the NPS during the Deep Water Horizon oil spill, many Regional Stream Quality Assessment tours of duty across the country, a wide assortment of scientific publications, and many other varied wonderful ways to make a living working for the USGS and DOI. He now is the Acting Assistant Director for Investigations in Georgia for the South Atlantic Water Science Center and wouldn’t trade a minute of the time spent with the people with whom he has the privilege of working.
Science and Products
Amphibian Research and Monitoring Initiative (ARMI) - Southeast Region Water Quality
The U.S. Geological Survey's (USGS) Amphibian Research and Monitoring Initiative (ARMI) began in 2000 with the goal of determining the status and trends of amphibian populations throughout the U.S. The program was designed to provide information useful in determining causes of declines or other changes in population distributions. Personnel in the South Atlantic Water Science Center are...
Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models
Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines...
Quantifying climate sensitivity and climate-driven change in North American amphibian communities
Changing climate will impact species’ ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >...
Miller, David A.W.; Campbell Grant, Evan H.; Muths, Erin L.; Amburgey, Staci M.; Adams, M.J.; Joseph, Maxwell B.; Waddle, J. Hardin; Johnson, Pieter T.J.; Ryan, Maureen E.; Schmidt, Benedikt R.; Calhoun, Daniel L.; Davis, Courtney L.; Fisher, Robert N.; Green, David M.; Hossack, Blake R.; Rittenhouse, Tracy A.G.; Walls, Susan C.; Bailey, Larissa L.; Cruickshank, Sam S.; Fellers, Gary M.; Gorman, Thomas A.; Haas, Carola A.; Hughson, Ward; Pilliod, David S.; Price, Steven J.; Ray, Andrew M.; Sadinski, Walter; Saenz, Daniel; Barichivich, William J.; Brand, Adrianne B,; Brehme, Cheryl S.; Dagit, Rosi; Delaney, Katy S.; Glorioso, Brad M.; Kats, Lee B.; Kleeman, Patrick M.; Pearl, Christopher; Rochester, Carlton J.; Riley, Seth P. D.; Roth, Mark F.; Sigafus, Brent Pathogenic lineage of Perkinsea associated with mass mortality of frogs across the United States
Emerging infectious diseases such as chytridiomycosis and ranavirus infections are important contributors to the worldwide decline of amphibian populations. We reviewed data on 247 anuran mortality events in 43 States of the United States from 1999–2015. Our findings suggest that a severe infectious disease of tadpoles caused by a protist...
Isidoro Ayza, Marcos; Lorch, Jeffrey M.; Grear, Daniel A.; Winzeler, Megan; Calhoun, Daniel L.; Barichivich, William J.
Five hydrologic and landscape databases for selected National Wildlife Refuges in the Southeastern United States
This report serves as metadata and a user guide for five out of six hydrologic and landscape databases developed by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, to describe data-collection, data-reduction, and data-analysis methods used to construct the databases and provides statistical and graphical...
Buell, Gary R.; Gurley, Laura N.; Calhoun, Daniel L.; Hunt, Alexandria M. Identifying small depressional wetlands and using a topographic position index to infer hydroperiod regimes for pond-breeding amphibians
Small, seasonal pools and temporary ponds (<4.0 ha) are the most numerous and biologically diverse wetlands in many natural landscapes. Thus, accurate determination of their numbers and spatial characteristics is beneficial for conservation and management of biodiversity associated with these freshwater systems. We examined the utility of a...
Riley, Jeffrey W.; Calhoun, Daniel L.; Barichivich, William J.; Walls, Susan C. Potential interactions among disease, pesticides, water quality and adjacent land cover in amphibian habitats in the United States
To investigate interactions among disease, pesticides, water quality, and adjacent land cover, we collected samples of water, sediment, and frog tissue from 21 sites in 7 States in the United States (US) representing a variety of amphibian habitats. All samples were analyzed for > 90 pesticides and pesticide degradates, and water and frogs...
Battaglin, William A.; Smalling, Kelly L. ; Anderson, Chauncey W.; Calhoun, Daniel L.; Chestnut, Tara E.; Muths, Erin L.
Spatial and temporal assessment of back-barrier erosion on Cumberland Island National Seashore, Georgia, 2011–2013
Much research has been conducted to better understand erosion and accretion processes for the seaward zones of coastal barrier islands; however, at Cumberland Island National Seashore, Georgia, the greater management concern is the effect that erosion is having on the resources of the island’s western shoreline, or the back barrier. Catastrophic...
Calhoun, Daniel L.; Riley, Jeffrey W. Assessment of environmental DNA for detecting presence of imperiled aquatic amphibian species in isolated wetlands
Environmental DNA (eDNA) is an emerging tool that allows low-impact sampling for aquatic species by isolating DNA from water samples and screening for DNA sequences specific to species of interest. However, researchers have not tested this method in naturally acidic wetlands that provide breeding habitat for a number of imperiled species,...
Mckee, Anna; Calhoun, Daniel L.; Barichivich, William J.; Spear, Stephen F.; Goldberg, Caren S.; Glenn, Travis C Contaminants in stream sediments from seven United States metropolitan areas: part I: distribution in relation to urbanization
Organic contaminants and trace elements were measured in bed sediments collected from streams in seven metropolitan study areas across the United States to assess concentrations in relation to urbanization. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, the pyrethroid insecticide bifenthrin, and several...
Nowell, Lisa H.; Moran, Patrick W.; Gilliom, Robert J.; Calhoun, Daniel L.; Ingersoll, Christopher G.; Kemble, Nile E.; Kuivila, Kathryn ; Phillips, Patrick J. Contaminants in stream sediments from seven United States metropolitan areas: part II—sediment toxicity to the amphipod Hyalella azteca and the midge Chironomus dilutus
Relationships between sediment toxicity and sediment chemistry were evaluated for 98 samples collected from seven metropolitan study areas across the United States. Sediment-toxicity tests were conducted with the amphipod Hyalella azteca (28 day exposures) and with the midge Chironomus dilutus (10 day exposures). Overall, 33 % of the samples were...
Kemble, Nile E.; Hardesty, Douglas K.; Ingersoll, Christopher G.; Kunz, James L.; Sibley, Paul K.; Calhoun, Daniel L.; Gilliom, Robert J.; Kuivila, Kathryn ; Nowell, Lisa H.; Moran, Patrick W. Occurrence and potential sources of pyrethroid insecticides in stream sediments from seven U.S. metropolitan areas
A nationally consistent approach was used to assess the occurrence and potential sources of pyrethroid insecticides in stream bed sediments from seven metropolitan areas across the United States. One or more pyrethroids were detected in almost half of the samples, with bifenthrin detected the most frequently (41%) and in each metropolitan area....
Kuivila, Kathryn ; Hladik, Michelle; Ingersoll, Christopher G.; Kemble, Nile E.; Moran, Patrick W.; Calhoun, Daniel L.; Nowell, Lisa H.; Gilliom, Robert J.
Analysis of the herbicide diuron, three diuron degradates, and six neonicotinoid insecticides in water-Method details and application to two Georgia streams
A method for the determination of the widely used herbicide diuron, three degradates of diuron, and six neonicotinoid insecticides in environmental water samples is described. Filtered water samples were extracted by using solid-phase extraction (SPE) with no additional cleanup steps. Quantification of the pesticides from the extracted water...
Hladik, Michelle; Calhoun, Daniel L.
Occurrence of pesticides in water and sediment collected from amphibian habitats located throughout the United States, 2009-10
Water and bed-sediment samples were collected by the U.S. Geological Survey (USGS) in 2009 and 2010 from 11 sites within California and 18 sites total in Colorado, Georgia, Idaho, Louisiana, Maine, and Oregon, and were analyzed for a suite of pesticides by the USGS. Water samples and bed-sediment samples were collected from perennial or seasonal...
Smalling, Kelly L.; Orlando, James L.; Calhoun, Daniel; Battaglin, William A.; Kuivila, Kathryn
Large-scale Review of Amphibian Species and Community Response to Climate Change
Amphibian species and community richness has been declining in North America and climate change may play a role in these declines. Global climate change has led to a range shift of many wildlife species and thus understanding how these changes in species distribution can be used to predict amphibian community responses that may improve conservation efforts.