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• 1. [Article] Host Identity Matters in the Amphibian- Batrachochytrium dendrobatidis System: Fine-Scale Patterns of Variation in Responses to a Multi-Host Pathogen

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Public ...

  Citation × Citation Citation Abstract Copy Title: Host Identity Matters in the Amphibian- Batrachochytrium dendrobatidis System: Fine-Scale Patterns of Variation in Responses to a Multi-Host Pathogen Author: Gervasi, Stephanie, Blaustein, Andrew R., Olson, Deanna H., Gondhalekar, Carmen To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Public Library of Science and can be found at: http://www.plosone.org/home.action. Title: Host Identity Matters in the Amphibian- Batrachochytrium dendrobatidis System: Fine-Scale Patterns of Variation in Responses to a Multi-Host Pathogen Author: Gervasi, Stephanie, Blaustein, Andrew R., Olson, Deanna H., Gondhalekar, Carmen To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Public Library of Science and can be found at: http://www.plosone.org/home.action. Close

• 2. [Article] The Role of Emerging Pathogens in Amphibian Population Declines : Experimental Evidence

  Rapid rates of biodiversity loss have supported the notion that Earth is experiencing a sixth major extinction event. The causes of worldwide biodiversity loss are multifaceted and context dependent. One ...

  Citation × Citation Citation Abstract Copy Title: The Role of Emerging Pathogens in Amphibian Population Declines : Experimental Evidence Author: Hambalek, Natalie M. Rapid rates of biodiversity loss have supported the notion that Earth is experiencing a sixth major extinction event. The causes of worldwide biodiversity loss are multifaceted and context dependent. One of the most prominent groups experiencing population declines and extinctions are amphibians. Several pathogens and their associated diseases are especially significant contributors to amphibian population declines. These include the chytrid fungus, Batrachochytrium dendrobatidis, the related but highly divergent fungal pathogen, B. salamandrivorans, and ranaviruses. In Chapter 1, I summarize the life-history traits of these three amphibian pathogens. In Chapter 2, I present a synthesis of these three emerging infectious pathogens by assessing their broad effects on amphibian hosts as found in experimental studies. I also examined the interactive effects of these pathogens with other potential and known contributors of amphibian population declines that have been experimentally studied. Well-designed experimental studies are critical for understanding the impacts of disease. However, inconsistencies in experimental methodologies often hinder our ability to form valuable comparisons and conclusions. Chapter 2 highlights the importance of implementing standard experimental protocols and reporting. Furthermore, we emphasize the significance of investigating the roles of multiple environmental and anthropogenic stressors. The effects of B. dendrobatidis and ranaviruses on their hosts have been well documented but the effects of coinfection with these pathogens are poorly understood. In Chapter 3, I experimentally examined the effects of simultaneous and independent exposure of B. dendrobatidis and ranavirus on survival, growth, and activity levels in two amphibian host species, the Pacific treefrog (Pseudacris regilla) and the western toad (Anaxyrus boreas). I predicted that coinfection with Bd and Rv would have increased lethal and sublethal effects on hosts compared with hosts that were infected with one of the pathogens independently. The results showed antagonistic effects of concurrent exposure to B. dendrobatidis and ranavirus, with individuals exposed to only one pathogen exhibiting more lethal and sublethal effects compared to individuals exposed to both pathogens. These results support the proposition that the dynamics behind multiple pathogen exposure are complex and that one pathogen may mitigate the effects of another to induce response variation. Title: The Role of Emerging Pathogens in Amphibian Population Declines : Experimental Evidence Author: Hambalek, Natalie M. Rapid rates of biodiversity loss have supported the notion that Earth is experiencing a sixth major extinction event. The causes of worldwide biodiversity loss are multifaceted and context dependent. One of the most prominent groups experiencing population declines and extinctions are amphibians. Several pathogens and their associated diseases are especially significant contributors to amphibian population declines. These include the chytrid fungus, Batrachochytrium dendrobatidis, the related but highly divergent fungal pathogen, B. salamandrivorans, and ranaviruses. In Chapter 1, I summarize the life-history traits of these three amphibian pathogens. In Chapter 2, I present a synthesis of these three emerging infectious pathogens by assessing their broad effects on amphibian hosts as found in experimental studies. I also examined the interactive effects of these pathogens with other potential and known contributors of amphibian population declines that have been experimentally studied. Well-designed experimental studies are critical for understanding the impacts of disease. However, inconsistencies in experimental methodologies often hinder our ability to form valuable comparisons and conclusions. Chapter 2 highlights the importance of implementing standard experimental protocols and reporting. Furthermore, we emphasize the significance of investigating the roles of multiple environmental and anthropogenic stressors. The effects of B. dendrobatidis and ranaviruses on their hosts have been well documented but the effects of coinfection with these pathogens are poorly understood. In Chapter 3, I experimentally examined the effects of simultaneous and independent exposure of B. dendrobatidis and ranavirus on survival, growth, and activity levels in two amphibian host species, the Pacific treefrog (Pseudacris regilla) and the western toad (Anaxyrus boreas). I predicted that coinfection with Bd and Rv would have increased lethal and sublethal effects on hosts compared with hosts that were infected with one of the pathogens independently. The results showed antagonistic effects of concurrent exposure to B. dendrobatidis and ranavirus, with individuals exposed to only one pathogen exhibiting more lethal and sublethal effects compared to individuals exposed to both pathogens. These results support the proposition that the dynamics behind multiple pathogen exposure are complex and that one pathogen may mitigate the effects of another to induce response variation. Close