Susan Walls, Ph.D.
Susan Walls is a research wildlife biologist who serves as the coordinator and lead scientist for the southeastern region of the Amphibian Research and Monitoring Initiative (ARMI).
ARMI is a national program for which funding was appropriated by Congress in 2000 in response to mounting evidence and concern for declines of amphibians in the U.S. and worldwide. Susan's research group establishes and implements long-term monitoring of amphibians at key sites within the southeastern U.S. (AL, GA, FL, SC, NC and TN) and conducts research on potential causes of declines. The team focuses on model-based monitoring to assess the impacts of climate change, emerging diseases, habitat restoration, and invasive species on amphibian communities.
Science and Products
Filter Total Items: 61
A new framework for analysing automated acoustic species detection data: Occupancy estimation and optimization of recordings post-processing A new framework for analysing automated acoustic species detection data: Occupancy estimation and optimization of recordings post-processing
The development and use of automated species-detection technologies, such as acoustic recorders, for monitoring wildlife are rapidly expanding. Automated classification algorithms provide a cost- and time-effective means to process information-rich data, but often at the cost of additional detection errors. Appropriate methods are necessary to analyse such data while dealing with the...
Authors
Thierry A. Chambert, J. Hardin Waddle, David A.W. Miller, Susan C. Walls, James D. Nichols
The significant surface-water connectivity of "geographically isolated wetlands" The significant surface-water connectivity of "geographically isolated wetlands"
We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be “geographically isolated” (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered...
Authors
Aram J.K. Calhoun, David M. Mushet, Laurie C. Alexander, Edward S. DeKeyser, Laurie Fowler, Charles R. Lane, Megan W. Lang, Mark C. Rains, Stephen Richter, Susan C. Walls
Identifying small depressional wetlands and using a topographic position index to infer hydroperiod regimes for pond-breeding amphibians Identifying small depressional wetlands and using a topographic position index to infer hydroperiod regimes for pond-breeding amphibians
Small, seasonal pools and temporary ponds (
Authors
Jeffrey W. Riley, Daniel L. Calhoun, William J. Barichivich, Susan C. Walls
Structured decision making as a conservation tool for recovery planning of two endangered salamanders Structured decision making as a conservation tool for recovery planning of two endangered salamanders
At least one-third of all amphibian species face the threat of extinction, and current amphibian extinction rates are four orders of magnitude greater than background rates. Preventing extirpation often requires both ex situ (i.e., conservation breeding programs) and in situ strategies (i.e., protecting natural habitats). Flatwoods salamanders (Ambystoma bishopi and A. cingulatum) are...
Authors
Katherine M. O’Donnell, Arianne F Messerman, William J. Barichivich, Raymond D. Semlitsch, Thomas A. Gorman, Harold G Mitchell, Nathan Allan, Dante B. Fenolio, Adam Green, Fred A. Johnson, Allison Keever, Mark Mandica, Julien Martin, Jana Mott, Terry Peacock, Joseph Reinman, Stephanie S. Romanach, Greg Titus, Conor P. McGowan, Susan C. Walls
Species interactions and the effects of climate variability on a wetland amphibian metacommunity Species interactions and the effects of climate variability on a wetland amphibian metacommunity
Disentangling the role that multiple interacting factors have on species responses to shifting climate poses a significant challenge. However, our ability to do so is of utmost importance to predict the effects of climate change on species distributions. We examined how populations of three species of wetland-breeding amphibians, which varied in life history requirements, responded to a...
Authors
Courtney L. Davis, David A.W. Miller, Susan C. Walls, William J. Barichivich, Jeffrey W. Riley, Mary E. Brown
Life history plasticity does not confer resilience to environmental change in the mole salamander (Ambystoma talpoideum) Life history plasticity does not confer resilience to environmental change in the mole salamander (Ambystoma talpoideum)
Plasticity in life history strategies can be advantageous for species that occupy spatially or temporally variable environments. We examined how phenotypic plasticity influences responses of the mole salamander, Ambystoma talpoideum, to disturbance events at the St. Marks National Wildlife Refuge (SMNWR), FL, USA from 2009 to 2014. We observed periods of extensive drought early in the...
Authors
Courtney L. Davis, David A.W. Miller, Susan C. Walls, William J. Barichivich, Jeffrey W. Riley, Mary E. Brown
Book review: Behavioral ecology of the eastern red-backed salamander: 50 years of research Book review: Behavioral ecology of the eastern red-backed salamander: 50 years of research
In commemoration of the 100th anniversary of the British Ecological Society, Sutherland et al. (2013) identified 100 questions of fundamental significance in “pure” (i.e., not applied) ecology. A somewhat unexpected outcome of these authors’ exercise was the realization that, after 100 years of comprehensive, intensive scientific research, there remained “profound knowledge gaps” in...
Authors
Susan C. Walls, Joseph C. Mitchell
Overcoming challenges to the recovery of declining amphibian populations in the United States Overcoming challenges to the recovery of declining amphibian populations in the United States
The US Endangered Species Act of 1973 (ESA) affords many potential benefits to species threatened with extinction. However, most at-risk amphibians—one of the most imperiled vertebrate groups—remain unlisted under the provisions of the ESA, and many impediments to recovery exist for those species that have been listed. Of the 35 US amphibian species and distinct population segments (...
Authors
Susan C. Walls, Lianne C. Ball, William J. Barichivich, Kenneth Dodd, Kevin M Enge, Thomas A. Gorman, Katherine M. O’Donnell, John G Palis, Raymond D. Semlitsch
Extinction debt as a driver of amphibian declines: An example with imperiled flatwoods salamanders Extinction debt as a driver of amphibian declines: An example with imperiled flatwoods salamanders
A comprehensive view of population declines and their underlying causes is necessary to reverse species loss. Historically, in many cases, a narrow view may have allowed species declines to continue, virtually undetected, for long periods of time (perhaps even decades). We suggest that extinction debt is likely responsible for numerous (perhaps most) amphibian declines and that this...
Authors
Raymond D Semiltsch, Susan C. Walls, William J. Barichivich, Katherine M. O’Donnell
Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines
Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a “smoking gun” was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased...
Authors
Evan H. Campbell Grant, David A. W. Miller, Benedikt R. Schmidt, M. J. Adams, Staci M. Amburgey, Thierry A. Chambert, Sam S. Cruickshank, Robert N. Fisher, David M. Green, Blake R. Hossack, Pieter T.J. Johnson, Maxwell B. Joseph, Tracy A. G. Rittenhouse, Maureen E. Ryan, J. Hardin Waddle, Susan C. Walls, Larissa L. Bailey, Gary M. Fellers, Thomas A. Gorman, Andrew M. Ray, David S. Pilliod, Steven J. Price, Daniel Saenz, Walt Sadinski, Erin L. Muths
Do geographically isolated wetlands influence landscape functions? Do geographically isolated wetlands influence landscape functions?
Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a...
Authors
Matthew J. Cohen, Irena F. Creed, Laurie C. Alexander, Nandita Basu, Aram J.K. Calhoun, Christopher Craft, Ellen D’Amico, Edward S. DeKeyser, Laurie Fowler, Heather E. Golden, James W. Jawitz, Peter Kalla, L. Katherine Kirkman, Charles R. Lane, Megan Lang, Scott G. Leibowitz, David Bruce Lewis, John Marton, Daniel L. McLaughlin, David M. Mushet, Hadas Raanan-Kiperwas, Mark C. Rains, Lora Smith, Susan C. Walls
Testing hypotheses on distribution shifts and changes in phenology of imperfectly detectable species Testing hypotheses on distribution shifts and changes in phenology of imperfectly detectable species
With ongoing climate change, many species are expected to shift their spatial and temporal distributions. To document changes in species distribution and phenology, detection/non-detection data have proven very useful. Occupancy models provide a robust way to analyse such data, but inference is usually focused on species spatial distribution, not phenology.We present a multi-season...
Authors
Thierry A. Chambert, William L. Kendall, James E. Hines, James D. Nichols, Paolo Pedrini, J. Hardin Waddle, Giacomo Tavecchia, Susan C. Walls, Simone Tenan
Science and Products
Filter Total Items: 61
A new framework for analysing automated acoustic species detection data: Occupancy estimation and optimization of recordings post-processing A new framework for analysing automated acoustic species detection data: Occupancy estimation and optimization of recordings post-processing
The development and use of automated species-detection technologies, such as acoustic recorders, for monitoring wildlife are rapidly expanding. Automated classification algorithms provide a cost- and time-effective means to process information-rich data, but often at the cost of additional detection errors. Appropriate methods are necessary to analyse such data while dealing with the...
Authors
Thierry A. Chambert, J. Hardin Waddle, David A.W. Miller, Susan C. Walls, James D. Nichols
The significant surface-water connectivity of "geographically isolated wetlands" The significant surface-water connectivity of "geographically isolated wetlands"
We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be “geographically isolated” (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered...
Authors
Aram J.K. Calhoun, David M. Mushet, Laurie C. Alexander, Edward S. DeKeyser, Laurie Fowler, Charles R. Lane, Megan W. Lang, Mark C. Rains, Stephen Richter, Susan C. Walls
Identifying small depressional wetlands and using a topographic position index to infer hydroperiod regimes for pond-breeding amphibians Identifying small depressional wetlands and using a topographic position index to infer hydroperiod regimes for pond-breeding amphibians
Small, seasonal pools and temporary ponds (
Authors
Jeffrey W. Riley, Daniel L. Calhoun, William J. Barichivich, Susan C. Walls
Structured decision making as a conservation tool for recovery planning of two endangered salamanders Structured decision making as a conservation tool for recovery planning of two endangered salamanders
At least one-third of all amphibian species face the threat of extinction, and current amphibian extinction rates are four orders of magnitude greater than background rates. Preventing extirpation often requires both ex situ (i.e., conservation breeding programs) and in situ strategies (i.e., protecting natural habitats). Flatwoods salamanders (Ambystoma bishopi and A. cingulatum) are...
Authors
Katherine M. O’Donnell, Arianne F Messerman, William J. Barichivich, Raymond D. Semlitsch, Thomas A. Gorman, Harold G Mitchell, Nathan Allan, Dante B. Fenolio, Adam Green, Fred A. Johnson, Allison Keever, Mark Mandica, Julien Martin, Jana Mott, Terry Peacock, Joseph Reinman, Stephanie S. Romanach, Greg Titus, Conor P. McGowan, Susan C. Walls
Species interactions and the effects of climate variability on a wetland amphibian metacommunity Species interactions and the effects of climate variability on a wetland amphibian metacommunity
Disentangling the role that multiple interacting factors have on species responses to shifting climate poses a significant challenge. However, our ability to do so is of utmost importance to predict the effects of climate change on species distributions. We examined how populations of three species of wetland-breeding amphibians, which varied in life history requirements, responded to a...
Authors
Courtney L. Davis, David A.W. Miller, Susan C. Walls, William J. Barichivich, Jeffrey W. Riley, Mary E. Brown
Life history plasticity does not confer resilience to environmental change in the mole salamander (Ambystoma talpoideum) Life history plasticity does not confer resilience to environmental change in the mole salamander (Ambystoma talpoideum)
Plasticity in life history strategies can be advantageous for species that occupy spatially or temporally variable environments. We examined how phenotypic plasticity influences responses of the mole salamander, Ambystoma talpoideum, to disturbance events at the St. Marks National Wildlife Refuge (SMNWR), FL, USA from 2009 to 2014. We observed periods of extensive drought early in the...
Authors
Courtney L. Davis, David A.W. Miller, Susan C. Walls, William J. Barichivich, Jeffrey W. Riley, Mary E. Brown
Book review: Behavioral ecology of the eastern red-backed salamander: 50 years of research Book review: Behavioral ecology of the eastern red-backed salamander: 50 years of research
In commemoration of the 100th anniversary of the British Ecological Society, Sutherland et al. (2013) identified 100 questions of fundamental significance in “pure” (i.e., not applied) ecology. A somewhat unexpected outcome of these authors’ exercise was the realization that, after 100 years of comprehensive, intensive scientific research, there remained “profound knowledge gaps” in...
Authors
Susan C. Walls, Joseph C. Mitchell
Overcoming challenges to the recovery of declining amphibian populations in the United States Overcoming challenges to the recovery of declining amphibian populations in the United States
The US Endangered Species Act of 1973 (ESA) affords many potential benefits to species threatened with extinction. However, most at-risk amphibians—one of the most imperiled vertebrate groups—remain unlisted under the provisions of the ESA, and many impediments to recovery exist for those species that have been listed. Of the 35 US amphibian species and distinct population segments (...
Authors
Susan C. Walls, Lianne C. Ball, William J. Barichivich, Kenneth Dodd, Kevin M Enge, Thomas A. Gorman, Katherine M. O’Donnell, John G Palis, Raymond D. Semlitsch
Extinction debt as a driver of amphibian declines: An example with imperiled flatwoods salamanders Extinction debt as a driver of amphibian declines: An example with imperiled flatwoods salamanders
A comprehensive view of population declines and their underlying causes is necessary to reverse species loss. Historically, in many cases, a narrow view may have allowed species declines to continue, virtually undetected, for long periods of time (perhaps even decades). We suggest that extinction debt is likely responsible for numerous (perhaps most) amphibian declines and that this...
Authors
Raymond D Semiltsch, Susan C. Walls, William J. Barichivich, Katherine M. O’Donnell
Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines
Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a “smoking gun” was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased...
Authors
Evan H. Campbell Grant, David A. W. Miller, Benedikt R. Schmidt, M. J. Adams, Staci M. Amburgey, Thierry A. Chambert, Sam S. Cruickshank, Robert N. Fisher, David M. Green, Blake R. Hossack, Pieter T.J. Johnson, Maxwell B. Joseph, Tracy A. G. Rittenhouse, Maureen E. Ryan, J. Hardin Waddle, Susan C. Walls, Larissa L. Bailey, Gary M. Fellers, Thomas A. Gorman, Andrew M. Ray, David S. Pilliod, Steven J. Price, Daniel Saenz, Walt Sadinski, Erin L. Muths
Do geographically isolated wetlands influence landscape functions? Do geographically isolated wetlands influence landscape functions?
Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a...
Authors
Matthew J. Cohen, Irena F. Creed, Laurie C. Alexander, Nandita Basu, Aram J.K. Calhoun, Christopher Craft, Ellen D’Amico, Edward S. DeKeyser, Laurie Fowler, Heather E. Golden, James W. Jawitz, Peter Kalla, L. Katherine Kirkman, Charles R. Lane, Megan Lang, Scott G. Leibowitz, David Bruce Lewis, John Marton, Daniel L. McLaughlin, David M. Mushet, Hadas Raanan-Kiperwas, Mark C. Rains, Lora Smith, Susan C. Walls
Testing hypotheses on distribution shifts and changes in phenology of imperfectly detectable species Testing hypotheses on distribution shifts and changes in phenology of imperfectly detectable species
With ongoing climate change, many species are expected to shift their spatial and temporal distributions. To document changes in species distribution and phenology, detection/non-detection data have proven very useful. Occupancy models provide a robust way to analyse such data, but inference is usually focused on species spatial distribution, not phenology.We present a multi-season...
Authors
Thierry A. Chambert, William L. Kendall, James E. Hines, James D. Nichols, Paolo Pedrini, J. Hardin Waddle, Giacomo Tavecchia, Susan C. Walls, Simone Tenan