Disease in amphibian populations can have a range of effects, from devastating declines following introduction of a novel pathogen to recurring breakout events on a landscape. Elucidating mechanisms underlying the effects of diseases on amphibian populations is crucial to help managers make appropriate decisions to achieve management goals for amphibians.
The Challenge: Batrochytrium dendrobatidis (Bd), has been found in the Northeast for decades, while ranavirus may have been more recently introduced; both cause massive mortality in some species and sites. An emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal), has caused mass mortality events and severe population declines in European salamanders via introduction into wild populations from the pet trade. Introduction of this pathogen to North America could be devastating, not only to local populations but also to global salamander biodiversity. However, little is known about how these diseases persist in habitats or the ability of individuals to clear infection. Elucidating mechanisms underlying the effects of diseases on amphibian populations is critical for helping managers make appropriate decisions to achieve management goals.
The Science: We have sampled for two diseases, Ranavirus and frog chytrid (Batrochytrium dendrobatidis, or Bd) on multiple refuges in the Northeast in conjunction with an analysis of soil contaminants to determine if local site factors can predict likelihood of disease outbreaks. ARMI is working collaboratively nationwide to determine the presence of Bsal in North American salamander populations in locations with increased risk of exposure to the Bsal pathogen. As part of a nation-wide study, NEARMI is monitoring a network of red-spotted newt populations (Notopthalmus viridescens) in a contiguous forest using mark-recapture techniques. Disease status of individuals and their use of habitat across the landscape is recorded through time.
The Future: Sampling for diseases such as Ranavirus and Bd will continue in the region, and Structured Decision Making workshops are underway to determine if refuges can collaboratively pursue amphibian management goals, including risk of disease. If Bsal is introduced to the Northeast, lessons learned from the study of Bd dynamics in amphibian populations can help inform management actions. In the interest of developing proactive management strategies, NEARMI’s research will help identify habitat conditions that may be useful for reducing population susceptibility.
Below are publications associated with this project.
Decision making for mitigating wildlife diseases: From theory to practice for an emerging fungal pathogen of amphibians
Effects of host species and environment on the skin microbiome of Plethodontid salamanders
Imperfect pathogen detection from non-invasive skin swabs biases disease inference
Identifying species conservation strategies to reduce disease-associated declines
Antifungal bacteria on woodland salamander skin exhibit high taxonomic diversity and geographic variability
Using decision analysis to support proactive management of emerging infectious wildlife diseases
A model to inform management actions as a response to chytridiomycosis-associated decline
Spatial variation in risk and consequence of Batrachochytrium salamandrivorans introduction in the USA
Salamander chytrid fungus (Batrachochytrium salamandrivorans) in the United States—Developing research, monitoring, and management strategies
Below are partners associated with this project.
- Overview
Disease in amphibian populations can have a range of effects, from devastating declines following introduction of a novel pathogen to recurring breakout events on a landscape. Elucidating mechanisms underlying the effects of diseases on amphibian populations is crucial to help managers make appropriate decisions to achieve management goals for amphibians.
The Challenge: Batrochytrium dendrobatidis (Bd), has been found in the Northeast for decades, while ranavirus may have been more recently introduced; both cause massive mortality in some species and sites. An emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal), has caused mass mortality events and severe population declines in European salamanders via introduction into wild populations from the pet trade. Introduction of this pathogen to North America could be devastating, not only to local populations but also to global salamander biodiversity. However, little is known about how these diseases persist in habitats or the ability of individuals to clear infection. Elucidating mechanisms underlying the effects of diseases on amphibian populations is critical for helping managers make appropriate decisions to achieve management goals.
The Science: We have sampled for two diseases, Ranavirus and frog chytrid (Batrochytrium dendrobatidis, or Bd) on multiple refuges in the Northeast in conjunction with an analysis of soil contaminants to determine if local site factors can predict likelihood of disease outbreaks. ARMI is working collaboratively nationwide to determine the presence of Bsal in North American salamander populations in locations with increased risk of exposure to the Bsal pathogen. As part of a nation-wide study, NEARMI is monitoring a network of red-spotted newt populations (Notopthalmus viridescens) in a contiguous forest using mark-recapture techniques. Disease status of individuals and their use of habitat across the landscape is recorded through time.
The Future: Sampling for diseases such as Ranavirus and Bd will continue in the region, and Structured Decision Making workshops are underway to determine if refuges can collaboratively pursue amphibian management goals, including risk of disease. If Bsal is introduced to the Northeast, lessons learned from the study of Bd dynamics in amphibian populations can help inform management actions. In the interest of developing proactive management strategies, NEARMI’s research will help identify habitat conditions that may be useful for reducing population susceptibility.
- Publications
Below are publications associated with this project.
Decision making for mitigating wildlife diseases: From theory to practice for an emerging fungal pathogen of amphibians
Conservation science can be most effective in its decision‐support role when seeking answers to clearly formulated questions of direct management relevance. Emerging wildlife diseases, a driver of global biodiversity loss, illustrate the challenges of performing this role: in spite of considerable research, successful disease mitigation is uncommon. Decision analysis is increasingly advocated to gAuthorsStefano Canessa, Claudio Bozzutto, Evan H. Campbell Grant, Sam S. Cruickshank, Matthew C. Fisher, Jacob C. Koella, Stefan Lotters, An Martel, Frank Pasmans, Ben C. Scheele, Annemarieke Spitzen-van der Sluijs, Sebastian Steinfartz, Benedikt R. SchmidtEffects of host species and environment on the skin microbiome of Plethodontid salamanders
The amphibian skin microbiome is recognized for its role in defence against pathogens, including the deadly fungal pathogen Batrachochytrium dendrobatidis (Bd). Yet, we have little understanding of evolutionary and ecological processes that structure these communities, especially for salamanders and closely related species. We investigated patterns in the distribution of bacterial communities on PAuthorsCarly R. Muletz-Wolz, Stephanie A. Yarwood, Evan H. Campbell Grant, Robert C. Fleischer, Karen R. LipsImperfect pathogen detection from non-invasive skin swabs biases disease inference
1. Conservation managers rely on accurate estimates of disease parameters, such as pathogen prevalence and infection intensity, to assess disease status of a host population. However, these disease metrics may be biased if low-level infection intensities are missed by sampling methods or laboratory diagnostic tests. These false negatives underestimate pathogen prevalence and overestimate mean infeAuthorsGraziella V. DiRenzo, Evan H. Campbell Grant, Ana V. Longo, Christian Che-Castaldo, Kelly R. Zamudio, Karen LipsIdentifying species conservation strategies to reduce disease-associated declines
Emerging infectious diseases (EIDs) are a salient threat to many animal taxa, causing local and global extinctions, altering communities and ecosystem function. The EID chytridiomycosis is a prominent driver of amphibian declines, which is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). To guide conservation policy, we developed a predictive decision-analytic model that combinesAuthorsBrian D. Gerber, Sarah J. Converse, Erin L. Muths, Harry J. Crockett, Brittany A. Mosher, Larissa L. BaileyAntifungal bacteria on woodland salamander skin exhibit high taxonomic diversity and geographic variability
Diverse bacteria inhabit amphibian skin; some of those bacteria inhibit growth of the fungal pathogen Batrachochytrium dendrobatidis. Yet there has been no systematic survey of anti-B. dendrobatidis bacteria across localities, species, and elevations. This is important given geographic and taxonomic variations in amphibian susceptibility to B. dendrobatidis. Our collection sites were at locationsAuthorsCarly R. Muletz-Wolz, Graziella V. DiRenzo, Stephanie A. Yarwood, Evan H. Campbell Grant, Robert C. Fleischer, Karen R. LipsUsing decision analysis to support proactive management of emerging infectious wildlife diseases
Despite calls for improved responses to emerging infectious diseases in wildlife, management is seldom considered until a disease has been detected in affected populations. Reactive approaches may limit the potential for control and increase total response costs. An alternative, proactive management framework can identify immediate actions that reduce future impacts even before a disease is detectAuthorsEvan H. Campbell Grant, Erin L. Muths, Rachel A. Katz, Stefano Canessa, M. J. Adams, Jennifer R. Ballard, Lee Berger, Cheryl J. Briggs, Jeremy T. H. Coleman, Matthew J. Gray, M. Camille Harris, Reid N. Harris, Blake R. Hossack, Kathryn P. Huyvaert, Jonathan E. Kolby, Karen R. Lips, Robert E. Lovich, Hamish I. McCallum, Joseph R. Mendelson, Priya Nanjappa, Deanna H. Olson, Jenny G. Powers, Katherine L. D. Richgels, Robin E. Russell, Benedikt R. Schmidt, Annemarieke Spitzen-van der Sluijs, Mary Kay Watry, Douglas C. Woodhams, C. LeAnn WhiteA model to inform management actions as a response to chytridiomycosis-associated decline
Decision-analytic models provide forecasts of how systems of interest will respond to management. These models can be parameterized using empirical data, but sometimes require information elicited from experts. When evaluating the effects of disease in species translocation programs, expert judgment is likely to play a role because complete empirical information will rarely be available. We illustAuthorsSarah J. Converse, Larissa L. Bailey, Brittany A. Mosher, W. Chris Funk, Brian D. Gerber, Erin L. MuthsSpatial variation in risk and consequence of Batrachochytrium salamandrivorans introduction in the USA
A newly identified fungal pathogen, Batrachochytrium salamandrivorans (Bsal), is responsible for mass mortality events and severe population declines in European salamanders. The eastern USA has the highest diversity of salamanders in the world and the introduction of this pathogen is likely to be devastating. Although data are inevitably limited for new pathogens, disease-risk assessments use besAuthorsKatherine L. D. Richgels, Robin E. Russell, M. J. Adams, C. LeAnn White, Evan H. Campbell GrantSalamander chytrid fungus (Batrachochytrium salamandrivorans) in the United States—Developing research, monitoring, and management strategies
The recently (2013) identified pathogenic chytrid fungus, Batrachochytrium salamandrivorans (Bsal), poses a severe threat to the distribution and abundance of salamanders within the United States and Europe. Development of a response strategy for the potential, and likely, invasion of Bsal into the United States is crucial to protect global salamander biodiversity. A formal working group, led by AAuthorsEvan H. Campbell Grant, Erin L. Muths, Rachel A. Katz, Stefano Canessa, M. J. Adams, Jennifer R. Ballard, Lee Berger, Cheryl J. Briggs, Jeremy T. H. Coleman, Matthew J. Gray, M. Camille Harris, Reid N. Harris, Blake R. Hossack, Kathryn P. Huyvaert, Jonathan E. Kolby, Karen R. Lips, Robert E. Lovich, Hamish I. McCallum, Joseph R. Mendelson, Priya Nanjappa, Deanna H. Olson, Jenny G. Powers, Katherine L. D. Richgels, Robin E. Russell, Benedikt R. Schmidt, Annemarieke Spitzen-van der Sluijs, Mary Kay Watry, Douglas C. Woodhams, C. LeAnn White - Partners
Below are partners associated with this project.