Hardin Waddle currently works as a research ecologist for the USGS, where he serves as the principal investigator for the south-central region of the Amphibian Research and Monitoring Initiative (ARMI). His research interests include population ecology and conservation of amphibians and reptiles, primarily in the wetlands and swamps of the southeastern United States.
EDUCATION
Ph.D., Wildlife Ecology, University of Florida, 2006
M.S. Biology, Florida International University, 2000
B.S., Wildlife Science, Auburn University, 1996
Science and Products
Filter Total Items: 18
Mark-Recapture Estimation of Razor-backed Musk Turtle Abundance in Louisiana
USGS scientists are working to determine the baseline population numbers of the Razor-backed Musk Turtle.
Understanding Avian Habitat Availability and Use After Barrier Island Restoration in Coastal Louisiana
Using ecological and geographical data, WARC researchers and their partners are analyzing avian and benthic sampling on Whiskey Island and Caminda Headland to compare pre- and post-restoration aspects of habitat occupancy, habitat availability, habitat use, and kernal density estimation.
Using Occupancy Analysis to Understand Ecological and Environmental Stressors that Affect the Range and Abundance of Gulf Coast Waterdogs (Necturus beyeri) in Louisiana Bayous
Sampling for Gulf Coast waterdogs is providing essential information to better understand the factors that impact the species' occupancy across Louisiana.
Monitoring and Removal of Invasive Cuban Treefrogs (Osteopilus septentrionalis) on the Gulf Coast
WARC researchers are performing visual encounter surveys and passively capturing Cuban treefrogs to remove as many of the invasive anurans as possible.
Effects of Saltwater Intrusion on Anuran Occupancy in Big Thicket National Preserve, Texas
WARC researchers sampled anuran populations at sites within Big Thicket National Preserve to explore saltwater intrusion on these populations.
Prevalence Rates of Snake Fungal Disease and Its Population-level Impacts in a Snake Assemblage in Southwest Louisiana
WARC researchers used visual encounter surveys to determine prevalence rates of snake fungal disease in south-central Louisiana.
Acoustic Monitoring for Two Rare Frog Species in Northwest Louisiana
WARC researchers are using automated recording units to monitor southern crawfish frogs and Strecker's chorus frogs in Louisiana.
Amphibian Research and Occupancy Modeling in the South-Central Region of the Amphibian Research and Monitoring Initiative (ARMI)
In response to growing public concerns about this loss of biodiversity, the U.S. Congress funded the Amphibian Research and Monitoring Initiative (ARMI), a national program coordinated by the U.S. Geological Survey.
Interaction of Environmental Stressors and Batrachochytrium dendrobatidis (Bd) Pathogen Loads on Survival of Green Frogs (Lithobates clamitans)
The U.S. Geological Survey Amphibian Research Monitoring Initiative (ARMI) is using a combination of swabbing, non-lethal tissue sampling, soil and water sampling, and collection of a variety of other environmental variables to determine the relationships between the prevalence and pathogen load of Bd infection and environmental stressors on green treefrog survival.
Diet and Reproductive Phenology in a Recently Established Population of Invasive Cuban Treefrogs (Osteopilus septentrionalis)
WARC researchers are exploring relationships between body size, time of year, sex, and reproductive development to better understand the reproductive phenology of the New Orleans population of Cuban treefrogs compared to Florida populations.
Alligator Snapping Turtle (Macrochelys temminckii) Research in Louisiana in Support of the Species Status Assessment and Listing Decision by the U.S. Fish and Wildlife Service
WARC researchers are investigating individual movement, growth, and population dynamics of alligator snapping turtles in a southwest Louisiana creek.
Capture-Mark-Recapture of Treefrogs at Bayou Teche National Wildlife Refuge
WARC researchers are gathering amphibian data to better understand the impact of natural disasters on treefrog populations and examine post-event processes.
Filter Total Items: 16
Data for analysis of open removal models with temporary emigration and population dynamics to inform invasive animal management
This data release includes the data and computer code that we produced to fit two open-robust design removal models developed to simultaneously model population dynamics, temporary emigration, and imperfect detection: a random walk linear trend model (estimable without ancillary information), and a 2-age class integrated population model (IPM) that used prior information for age-structured vital r
Data from a 2019 occupancy survey of alligator snapping turtles, Macrochelys temminckii, in south-central Louisiana
This dataset contains data on trapping methodology, turtle captures, and environmental variables from a trapping effort targeting alligator snapping turtles (Macrochelys temminckii) in south-central Louisiana in 2019.
Data from a turtle trapping effort targeting alligator snapping turtles (Macrochelys temminckii) in the Atchafalaya Basin beginning in 2019
This dataset contains data from an ongoing trapping effort beginning in 2019 targeting alligator snapping turtles (Macrochelys temminckii) in the Atchafalaya Basin of south-central Louisiana.
Data from: ''Evaluating the effect of expert elicitation techniques on population status assessment in the face of large uncertainty''
The dataset contains estimates (low, estimate, high) of 12 population parameters for the wood turtle (Glyptemys insculpta) from the literature and experts.
Data for Estimating detection and occupancy of secretive marsh bird species in low and high saline marshes in southwestern Louisiana using automated recording units
This dataset compiles all data used in a study on occupancy of secretive marsh birds collected from automated audio recording units in southwest Louisiana. The main data files consist of detection histories for the 11 species across 20 sampling occasions at 33 sites. The sites were randomly selected, and all site level information is provided, including coordinates, marsh type, and habitat designa
Data from visual encounter and acoustic monitoring surveys targeting amphibians and reptiles in Big Thicket National Preserve in southeast Texas from August 2010 to September 2018
This dataset contains data from visual encounter and acoustic surveys in Big Thicket National Preserve in Texas from August 2010 to September 2018. This dataset also includes salinity measurements from nine salinity loggers deployed in the study area.
Data from a 2015 trapping survey targeting the Gulf Coast Waterdog, Necturus beyeri, in Saint Tammany Parish, Louisiana
This dataset provides the data associated with a 2015 project to examine factors affecting the occupancy of Gulf Coast Waterdogs along Bayou Lacombe, Saint Tammany Parish, Louisiana. Data include site locations and distance from headwaters, water data (pH, turbidity, salinity, and depth), and capture data from trap checks. For Necturus beyeri captures, the datatset provides the sex of captures and
Amphibian monitoring data collected from Indiana hardwood forests, 2015-2016
This data set contains information on detections of amphibians at four bottomland hardwood restoration sites in northeastern Indiana in 2015 and 2016. Amphibian communities were surveyed using four different methods - automated recording units, diurnal visual encounter surveys along transects, nocturnal transect surveys, and amphibian rapid assessments. The data set contains three tables: 1) site
Data from a national survey for the amphibian chytrid fungus Batrachochytrium salamandrivorans
This dataset provides the results of a national survey of the conterminous U.S. for the salamander chytrid fungus Batrachochytrium salamandrivorans (Bsal) conducted by the U.S. Geological Survey Amphibian Research and Monitoring Initiative from May 2014 to August 2017. Sites were sampled by capturing amphibians by hand or by traps or nets that were then swabbed individually using methods that prev
Body measurements of the exotic invasive Cuban treefrog (Osteopilus septentrionalis) in Louisiana
This dataset provides location and standard measurements of captured Cuban Treefrogs from the Audubon Park and Zoo area of New Orleans, Louisiana.
Computer automated frog vocalization results from Picayune Strand State Forest, Florida 2011-2012
This dataset includes the results of a computer automated anuran vocalization recognition analysis of audio recordings made at Picayune Strand State Forest in 2011 and 2012. The audio files were scanned for 11 species of frogs and toads using the commercially available software program Song Scope (ver. 4.1.3). All detections by the software are listed here along with a "result" field which indicat
Bd and Bsal prevalence in Gulf Coast waterdogs captured from St. Tammany Parish, Louisiana, in 2015
The dataset includes information on all 76 Gulf Coast Waterdogs captured including sex and size information along with the results of the tests for the two fungal pathogens.
Filter Total Items: 58
Burmese pythons in Florida: A synthesis of biology, impacts, and management tools
Burmese pythons (Python molurus bivittatus) are native to southeastern Asia, however, there is an established invasive population inhabiting much of southern Florida throughout the Greater Everglades Ecosystem. Pythons have severely impacted native species and ecosystems in Florida and represent one of the most intractable invasive-species management issues across the globe. The difficulty stems f
Range-wide population projections for Northern Red-Bellied Cooters (Pseudemys rubriventris)
Northern Red-Bellied Cooters (Pseudemys rubriventris) have a disjunct distribution with a relictual population in southeastern Massachusetts and a larger range across the mid-Atlantic United States. The relictual population is currently listed with protections under the U.S. Endangered Species Act but the status of the population in the remainder of the species' range has not been assessed, and th
Open removal models with temporary emigration and population dynamics to inform invasive animal management
Removal sampling data are the primary source of monitoring information for many populations (e.g., invasive species, fisheries). Population dynamics, temporary emigration, and imperfect detection are common sources of variation in monitoring data and are key parameters for informing management. We developed two open robust-design removal models for simultaneously modeling population dynamics, temp
Estimating detection and occupancy of secretive marsh bird species in low and high saline marshes in southwestern Louisiana using automated recording units
Secretive marsh birds (SMBs) are important indicator species of coastal wetlands but are difficult to detect and monitor. In coastal Louisiana, an important stronghold for these species, climate and hydrological models predict that freshwater and intermediate marshes will expand in the next 50 years, while brackish marshes will shrink. We used a multi-species Bayesian hierarchical occupancy model
Evaluating the effect of expert elicitation techniques on population status assessment in the face of large uncertainty
Population projection models are important tools for conservation and management. They are often used for population status assessments, for threat analyses, and to predict the consequences of conservation actions. Although conservation decisions should be informed by science, critical decisions are often made with very little information to support decision-making. Conversely, postponing decision
Hierarchical models improve the use of alligator abundance as an indicator
Indicator species are species which can be monitored as an index to measure the overall health of an ecosystem. Crocodylians have been shown to be good indicators of wetland condition as they respond to changes in hydrology, can be efficiently monitored, and are a key part of ecosystem trophic relationships. Eye shine surveys at night are a standard method used to sample alligators, but because so
Changes in vegetation structure and gopher tortoise population structure after 17 years of restoration management
We examined a study plot sampled in the Conecuh National Forest of southern Alabama in 1999 and again in 2016 after stand thinning and persistent prescribed fire were used to improve habitat quality. These management activities were designed, in part, to enhance habitat quality for the gopher tortoise (Gopherus polyphemus), a species considered for protection under the Endangered Species Act becau
Abundance of Gulf Coast Waterdogs (Necturus beyeri) along Bayou Lacombe, Saint Tammany Parish, Louisiana
Few ecological studies have been conducted on Gulf Coast Waterdogs (Necturus beyeri), and published studies have focused on relatively small stream sections of 125 m to 1.75 km. In 2015, we sampled 25 sites along a 13.4-km stretch of Bayou Lacombe (Saint Tammany Parish, Louisiana, USA) to better understand factors that may influence the distribution of Gulf Coast Waterdogs within streams. We check
Demographic responses to density-dependence by two populations of the Florida Tree Snail, Liguus fasciatus (Gastropoda: Orthalicidae), in Everglades National Park
During May-October 1996, we captured and individually marked and released Florida Tree Snails, Liguus fasciatus, from two sites, a subclimax hammock and a large isolated wild tamarind tree, in the Long Pine Key region of Everglades National Park. Populations shared the same two dominant morphs, castaneozonatus and. cingulatus, both of which are strong colonizers. Monthly survivorship between the t
Widespread Ranavirus and Perkinsea infections in Cuban treefrogs (Osteopilus septentrionalis) invading New Orleans, USA
Invasive species can negatively impact ecosystems in numerous ways, including vectoring pathogenic organisms. In amphibians, a lineage globally threatened by multiple pathogens, this spread of disease via invasive species could contribute to declines in native populations. The Cuban Treefrog (Osteopilus septentrionalis) is invasive in the southeastern USA. To assess whether O. septentrionalis is a
Tropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures
Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward‐moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold‐sensitive tropical organisms, sometimes at the expense of temperate organisms. Althoug
Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians
The salamander chytrid fungus (Batrachochytrium salamandrivorans [Bsal]) is causing massive mortality of salamanders in Europe. The potential for spread via international trade into North America and the high diversity of salamanders has catalyzed concern about Bsal in the U.S. Surveillance programs for invading pathogens must initially meet challenges that include low rates of occurrence on the l
Science and Products
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Filter Total Items: 18
Mark-Recapture Estimation of Razor-backed Musk Turtle Abundance in Louisiana
USGS scientists are working to determine the baseline population numbers of the Razor-backed Musk Turtle.Understanding Avian Habitat Availability and Use After Barrier Island Restoration in Coastal Louisiana
Using ecological and geographical data, WARC researchers and their partners are analyzing avian and benthic sampling on Whiskey Island and Caminda Headland to compare pre- and post-restoration aspects of habitat occupancy, habitat availability, habitat use, and kernal density estimation.Using Occupancy Analysis to Understand Ecological and Environmental Stressors that Affect the Range and Abundance of Gulf Coast Waterdogs (Necturus beyeri) in Louisiana Bayous
Sampling for Gulf Coast waterdogs is providing essential information to better understand the factors that impact the species' occupancy across Louisiana.Monitoring and Removal of Invasive Cuban Treefrogs (Osteopilus septentrionalis) on the Gulf Coast
WARC researchers are performing visual encounter surveys and passively capturing Cuban treefrogs to remove as many of the invasive anurans as possible.Effects of Saltwater Intrusion on Anuran Occupancy in Big Thicket National Preserve, Texas
WARC researchers sampled anuran populations at sites within Big Thicket National Preserve to explore saltwater intrusion on these populations.Prevalence Rates of Snake Fungal Disease and Its Population-level Impacts in a Snake Assemblage in Southwest Louisiana
WARC researchers used visual encounter surveys to determine prevalence rates of snake fungal disease in south-central Louisiana.Acoustic Monitoring for Two Rare Frog Species in Northwest Louisiana
WARC researchers are using automated recording units to monitor southern crawfish frogs and Strecker's chorus frogs in Louisiana.Amphibian Research and Occupancy Modeling in the South-Central Region of the Amphibian Research and Monitoring Initiative (ARMI)
In response to growing public concerns about this loss of biodiversity, the U.S. Congress funded the Amphibian Research and Monitoring Initiative (ARMI), a national program coordinated by the U.S. Geological Survey.Interaction of Environmental Stressors and Batrachochytrium dendrobatidis (Bd) Pathogen Loads on Survival of Green Frogs (Lithobates clamitans)
The U.S. Geological Survey Amphibian Research Monitoring Initiative (ARMI) is using a combination of swabbing, non-lethal tissue sampling, soil and water sampling, and collection of a variety of other environmental variables to determine the relationships between the prevalence and pathogen load of Bd infection and environmental stressors on green treefrog survival.Diet and Reproductive Phenology in a Recently Established Population of Invasive Cuban Treefrogs (Osteopilus septentrionalis)
WARC researchers are exploring relationships between body size, time of year, sex, and reproductive development to better understand the reproductive phenology of the New Orleans population of Cuban treefrogs compared to Florida populations.Alligator Snapping Turtle (Macrochelys temminckii) Research in Louisiana in Support of the Species Status Assessment and Listing Decision by the U.S. Fish and Wildlife Service
WARC researchers are investigating individual movement, growth, and population dynamics of alligator snapping turtles in a southwest Louisiana creek.Capture-Mark-Recapture of Treefrogs at Bayou Teche National Wildlife Refuge
WARC researchers are gathering amphibian data to better understand the impact of natural disasters on treefrog populations and examine post-event processes. - Data
Filter Total Items: 16
Data for analysis of open removal models with temporary emigration and population dynamics to inform invasive animal management
This data release includes the data and computer code that we produced to fit two open-robust design removal models developed to simultaneously model population dynamics, temporary emigration, and imperfect detection: a random walk linear trend model (estimable without ancillary information), and a 2-age class integrated population model (IPM) that used prior information for age-structured vital rData from a 2019 occupancy survey of alligator snapping turtles, Macrochelys temminckii, in south-central Louisiana
This dataset contains data on trapping methodology, turtle captures, and environmental variables from a trapping effort targeting alligator snapping turtles (Macrochelys temminckii) in south-central Louisiana in 2019.Data from a turtle trapping effort targeting alligator snapping turtles (Macrochelys temminckii) in the Atchafalaya Basin beginning in 2019
This dataset contains data from an ongoing trapping effort beginning in 2019 targeting alligator snapping turtles (Macrochelys temminckii) in the Atchafalaya Basin of south-central Louisiana.Data from: ''Evaluating the effect of expert elicitation techniques on population status assessment in the face of large uncertainty''
The dataset contains estimates (low, estimate, high) of 12 population parameters for the wood turtle (Glyptemys insculpta) from the literature and experts.Data for Estimating detection and occupancy of secretive marsh bird species in low and high saline marshes in southwestern Louisiana using automated recording units
This dataset compiles all data used in a study on occupancy of secretive marsh birds collected from automated audio recording units in southwest Louisiana. The main data files consist of detection histories for the 11 species across 20 sampling occasions at 33 sites. The sites were randomly selected, and all site level information is provided, including coordinates, marsh type, and habitat designaData from visual encounter and acoustic monitoring surveys targeting amphibians and reptiles in Big Thicket National Preserve in southeast Texas from August 2010 to September 2018
This dataset contains data from visual encounter and acoustic surveys in Big Thicket National Preserve in Texas from August 2010 to September 2018. This dataset also includes salinity measurements from nine salinity loggers deployed in the study area.Data from a 2015 trapping survey targeting the Gulf Coast Waterdog, Necturus beyeri, in Saint Tammany Parish, Louisiana
This dataset provides the data associated with a 2015 project to examine factors affecting the occupancy of Gulf Coast Waterdogs along Bayou Lacombe, Saint Tammany Parish, Louisiana. Data include site locations and distance from headwaters, water data (pH, turbidity, salinity, and depth), and capture data from trap checks. For Necturus beyeri captures, the datatset provides the sex of captures andAmphibian monitoring data collected from Indiana hardwood forests, 2015-2016
This data set contains information on detections of amphibians at four bottomland hardwood restoration sites in northeastern Indiana in 2015 and 2016. Amphibian communities were surveyed using four different methods - automated recording units, diurnal visual encounter surveys along transects, nocturnal transect surveys, and amphibian rapid assessments. The data set contains three tables: 1) siteData from a national survey for the amphibian chytrid fungus Batrachochytrium salamandrivorans
This dataset provides the results of a national survey of the conterminous U.S. for the salamander chytrid fungus Batrachochytrium salamandrivorans (Bsal) conducted by the U.S. Geological Survey Amphibian Research and Monitoring Initiative from May 2014 to August 2017. Sites were sampled by capturing amphibians by hand or by traps or nets that were then swabbed individually using methods that prevBody measurements of the exotic invasive Cuban treefrog (Osteopilus septentrionalis) in Louisiana
This dataset provides location and standard measurements of captured Cuban Treefrogs from the Audubon Park and Zoo area of New Orleans, Louisiana.Computer automated frog vocalization results from Picayune Strand State Forest, Florida 2011-2012
This dataset includes the results of a computer automated anuran vocalization recognition analysis of audio recordings made at Picayune Strand State Forest in 2011 and 2012. The audio files were scanned for 11 species of frogs and toads using the commercially available software program Song Scope (ver. 4.1.3). All detections by the software are listed here along with a "result" field which indicatBd and Bsal prevalence in Gulf Coast waterdogs captured from St. Tammany Parish, Louisiana, in 2015
The dataset includes information on all 76 Gulf Coast Waterdogs captured including sex and size information along with the results of the tests for the two fungal pathogens. - Multimedia
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Filter Total Items: 58
Burmese pythons in Florida: A synthesis of biology, impacts, and management tools
Burmese pythons (Python molurus bivittatus) are native to southeastern Asia, however, there is an established invasive population inhabiting much of southern Florida throughout the Greater Everglades Ecosystem. Pythons have severely impacted native species and ecosystems in Florida and represent one of the most intractable invasive-species management issues across the globe. The difficulty stems fRange-wide population projections for Northern Red-Bellied Cooters (Pseudemys rubriventris)
Northern Red-Bellied Cooters (Pseudemys rubriventris) have a disjunct distribution with a relictual population in southeastern Massachusetts and a larger range across the mid-Atlantic United States. The relictual population is currently listed with protections under the U.S. Endangered Species Act but the status of the population in the remainder of the species' range has not been assessed, and thOpen removal models with temporary emigration and population dynamics to inform invasive animal management
Removal sampling data are the primary source of monitoring information for many populations (e.g., invasive species, fisheries). Population dynamics, temporary emigration, and imperfect detection are common sources of variation in monitoring data and are key parameters for informing management. We developed two open robust-design removal models for simultaneously modeling population dynamics, tempEstimating detection and occupancy of secretive marsh bird species in low and high saline marshes in southwestern Louisiana using automated recording units
Secretive marsh birds (SMBs) are important indicator species of coastal wetlands but are difficult to detect and monitor. In coastal Louisiana, an important stronghold for these species, climate and hydrological models predict that freshwater and intermediate marshes will expand in the next 50 years, while brackish marshes will shrink. We used a multi-species Bayesian hierarchical occupancy modelEvaluating the effect of expert elicitation techniques on population status assessment in the face of large uncertainty
Population projection models are important tools for conservation and management. They are often used for population status assessments, for threat analyses, and to predict the consequences of conservation actions. Although conservation decisions should be informed by science, critical decisions are often made with very little information to support decision-making. Conversely, postponing decisionHierarchical models improve the use of alligator abundance as an indicator
Indicator species are species which can be monitored as an index to measure the overall health of an ecosystem. Crocodylians have been shown to be good indicators of wetland condition as they respond to changes in hydrology, can be efficiently monitored, and are a key part of ecosystem trophic relationships. Eye shine surveys at night are a standard method used to sample alligators, but because soChanges in vegetation structure and gopher tortoise population structure after 17 years of restoration management
We examined a study plot sampled in the Conecuh National Forest of southern Alabama in 1999 and again in 2016 after stand thinning and persistent prescribed fire were used to improve habitat quality. These management activities were designed, in part, to enhance habitat quality for the gopher tortoise (Gopherus polyphemus), a species considered for protection under the Endangered Species Act becauAbundance of Gulf Coast Waterdogs (Necturus beyeri) along Bayou Lacombe, Saint Tammany Parish, Louisiana
Few ecological studies have been conducted on Gulf Coast Waterdogs (Necturus beyeri), and published studies have focused on relatively small stream sections of 125 m to 1.75 km. In 2015, we sampled 25 sites along a 13.4-km stretch of Bayou Lacombe (Saint Tammany Parish, Louisiana, USA) to better understand factors that may influence the distribution of Gulf Coast Waterdogs within streams. We checkDemographic responses to density-dependence by two populations of the Florida Tree Snail, Liguus fasciatus (Gastropoda: Orthalicidae), in Everglades National Park
During May-October 1996, we captured and individually marked and released Florida Tree Snails, Liguus fasciatus, from two sites, a subclimax hammock and a large isolated wild tamarind tree, in the Long Pine Key region of Everglades National Park. Populations shared the same two dominant morphs, castaneozonatus and. cingulatus, both of which are strong colonizers. Monthly survivorship between the tWidespread Ranavirus and Perkinsea infections in Cuban treefrogs (Osteopilus septentrionalis) invading New Orleans, USA
Invasive species can negatively impact ecosystems in numerous ways, including vectoring pathogenic organisms. In amphibians, a lineage globally threatened by multiple pathogens, this spread of disease via invasive species could contribute to declines in native populations. The Cuban Treefrog (Osteopilus septentrionalis) is invasive in the southeastern USA. To assess whether O. septentrionalis is aTropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures
Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward‐moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold‐sensitive tropical organisms, sometimes at the expense of temperate organisms. AlthougBatrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians
The salamander chytrid fungus (Batrachochytrium salamandrivorans [Bsal]) is causing massive mortality of salamanders in Europe. The potential for spread via international trade into North America and the high diversity of salamanders has catalyzed concern about Bsal in the U.S. Surveillance programs for invading pathogens must initially meet challenges that include low rates of occurrence on the l - News