Download or read book Batrachochytrium Dendrobatidis Prevalence in Northern Red legged Frogs Rana Aurora written by Michael Cheng Sun and published by . This book was released on 2012 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prevalence of Chytridiomycosis in Red legged Frog Rana Aurora Aurora Larvae in and Around Redwood National Park Northern Coastal California with Notes on Other Parasites written by Nathan C. Nieto and published by . This book was released on 2004 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Ecology of Chytridiomycosis in Red legged Frog Rana Aurora Tadpoles written by Phineas Hamilton and published by . This book was released on 2010 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chytridiomycosis is an emerging infectious disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Chytridiomycosis has caused declines and extinctions of amphibian species worldwide. Although the disease can be highly virulent, there are large differences both within and between amphibian species in response to Bd-infection. Environmental factors are increasingly shown to be critical in the outcome of Bd-infection and emergence of the disease, although these factors remain poorly defined. Using a series of mesocosm experiments, I examine the influence of different environmental and ecological factors on the outcome of exposure to Bd in red-leggedfrog (Rana aurora) tadpoles, a species in decline in British Columbia. First, I tested the hypothesis that Daphnia, a keystone genus of zooplankton in shallow freshwater ecosystems, consume Bd zoospores in the water column to decrease the transmission of Bd infection in tadpoles. Although Daphnia are nearly always included in amphibian mesocosm experiments, their effects in these systems are overlooked. As such, I also examined the effect of Daphnia on R. aurora in general. I found that Daphnia had dramatic beneficial effects on tadpoles, that ostensibly herbivorous tadpoles consumed large numbers of Daphnia, and that Daphnia interacted with the presence of Bd to influence tadpole survival, with tadpole survival highest in the absence of Bd and presence of Daphnia. Although Daphnia consumed Bd zoospores in the laboratory, they had no discernible effect on transmission in mesocosms. These results have broad implications for the interpretation of mesocosm studies in general. Climate change has been implicated as a trigger of outbreaks of chytridiomycosis, yet, paradoxically, high temperatures are lethal to Bd. Climate change has also impacted amphibian communities by uncoupling the phenology of interacting species. I manipulated the temperature in mesocosms to test the effects of small temperature changes on the outcome of Bd-exposure in R. aurora. I also tested the effect of the presence of the sympatric Boreal chorus frog (Pseudacris regilla) on R. aurora at different temperatures, and in the presence and absence of Bd. I found that negative effects of Bd on tadpole body condition increased with temperature, although when Bd was absent tadpoles benefitted at higher temperatures. Furthermore, both Bd and temperature increased the development rates of P. regilla but not R. aurora, uncoupling the phenology of the species. Increased temperatures thus favoured P. regilla at the expense of R. aurora. In general, slightly higher and more variable temperatures shifted the host-pathogen balance to the detriment of the R. aurora, helping to explain a mechanism by which increasing temperatures may trigger chytridiomycosis outbreaks in susceptible. Together, these experiments clearly demonstrated the importance of ecological context in the outcome of Bd exposure in tadpoles.
Download or read book The Ecology of Chytridiomycosis in Red legged Frog Rana Aurora Tadpoles written by Phineas T. Hamilton and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chytridiomycosis is an emerging infectious disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Chytridiomycosis has caused declines and extinctions of amphibian species worldwide. Although the disease can be highly virulent, there are large differences both within and between amphibian species in response to Bd-infection. Environmental factors are increasingly shown to be critical in the outcome of Bd-infection and emergence of the disease, although these factors remain poorly defined. Using a series of mesocosm experiments, I examine the influence of different environmental and ecological factors on the outcome of exposure to Bd in red-leggedfrog (Rana aurora) tadpoles, a species in decline in British Columbia. First, I tested the hypothesis that Daphnia, a keystone genus of zooplankton in shallow freshwater ecosystems, consume Bd zoospores in the water column to decrease the transmission of Bd infection in tadpoles. Although Daphnia are nearly always included in amphibian mesocosm experiments, their effects in these systems are overlooked. As such, I also examined the effect of Daphnia on R. aurora in general. I found that Daphnia had dramatic beneficial effects on tadpoles, that ostensibly herbivorous tadpoles consumed large numbers of Daphnia, and that Daphnia interacted with the presence of Bd to influence tadpole survival, with tadpole survival highest in the absence of Bd and presence of Daphnia. Although Daphnia consumed Bd zoospores in the laboratory, they had no discernible effect on transmission in mesocosms. These results have broad implications for the interpretation of mesocosm studies in general. Climate change has been implicated as a trigger of outbreaks of chytridiomycosis, yet, paradoxically, high temperatures are lethal to Bd. Climate change has also impacted amphibian communities by uncoupling the phenology of interacting species. I manipulated the temperature in mesocosms to test the effects of small temperature changes on the outcome of Bd-exposure in R. aurora. I also tested the effect of the presence of the sympatric Boreal chorus frog (Pseudacris regilla) on R. aurora at different temperatures, and in the presence and absence of Bd. I found that negative effects of Bd on tadpole body condition increased with temperature, although when Bd was absent tadpoles benefitted at higher temperatures. Furthermore, both Bd and temperature increased the development rates of P. regilla but not R. aurora, uncoupling the phenology of the species. Increased temperatures thus favoured P. regilla at the expense of R. aurora. In general, slightly higher and more variable temperatures shifted the host-pathogen balance to the detriment of the R. aurora, helping to explain a mechanism by which increasing temperatures may trigger chytridiomycosis outbreaks in susceptible. Together, these experiments clearly demonstrated the importance of ecological context in the outcome of Bd exposure in tadpoles.
Download or read book Prevalence of the Pathogenic Chytrid Fungus i Batrachochytrium Dendrobatidis i in an Endangered Population of Northern Leopard Frogs i Rana Pipiens i written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Multiple Stressors written by Lindsey L. Gordon and published by . This book was released on 2020 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: As human activities reach every corner of the globe, climate change, invasive species, habitat destruction, and other stressors causing species’ declines no longer act alone. Climate change has the potential to exacerbate (or mitigate) other stressors (e.g. invasive species or pathogens) affecting amphibian populations. I assessed the combined effects of increased pond drying rates (potential impact of climate change), invasive bullfrogs (Lithobates catesbeianus) presence, and food availability on northern red-legged frog (Rana aurora) survival and body size after metamorphosis by rearing tadpoles under incrementally shortened hydroperiods with and without the presence of invasive bullfrog tadpoles in low and high food environments. To explore the underlying mechanisms driving the impact of bullfrogs on R. aurora tadpoles, I had two treatments where bullfrog tadpoles were either separated by a permeable barrier (behavioral cue) or free to move about the tanks (direct competition/predation). To validate the captive experiment, I examined the influence of hydroperiod length on R. aurora survival, development, and growth in a field-based mesocosm experiment. I found hydroperiod to have a threshold effect on survival through metamorphosis in the captive experiment. Once the hydroperiod threshold was met in both the captive and field study, I found no benefit of longer hydroperiods on survival through metamorphosis. Drying rate influenced R. aurora developmental rates, but the effects were dependent on life stage and time of season in the field study. Size at metamorphosis was synergistically affected by bullfrog presence and food availability in the captive experiment. Tadpoles emerged as smaller metamorphs when exposed to bullfrogs in a low food environment. In the field experiment, size at metamorphosis was positively affected by longer hydroperiod and later emergence date. Understanding how multiple stressors impact larval growth and survival is an important component for managing and potentially mitigating the interactive effects of climate change and invasive species for amphibian conservation.
Download or read book COSEWIC Assessment and Update Status Report on the Red legged Frog Rana Aurora in Canada electronic Resource written by Committee on the Status of Endangered Wildlife in Canada and published by COSEWIC Secretariat, Canadian Wildlife Service. This book was released on 2004 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The red-legged frog is one of the six species of true frogs native to North America, an inhabitant of moist, lower elevation forests. In Canada, it is found on Vancouver Island, on several Strait of Georgia islands, and on the adjacent mainland. This report provides an assessment of the status of this species. It includes information on its classification, physical characteristics, geographic distribution, habitat, biology (reproduction, survival, predators, physiology, movements, dispersal, nutrition, behaviour, adaptability), population sizes & trends, the factors & threats limiting the population, the special significance of the species, and existing protection or other status of the species.
Download or read book Post breeding Movements and Habitat Use by the Northern Red legged Frog Rana Aurora Aurora at Dempsey Creek Thurston County Washington written by Jennifer Tuesday Serra Shean and published by . This book was released on 2002 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Viability of the Red legged Frogs Rana Aurora Introduced in the Reed College Canyon written by Xeno Acharya and published by . This book was released on 2008 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Northern Red legged Frog Rana Aurora Aurora Terrestrial Habitat Use in the Puget Lowlands of Washington written by Joanne P. Schuett-Hames and published by . This book was released on 2004 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ranaviruses written by Matthew J. Gray and published by Springer. This book was released on 2015-05-01 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book on ranaviruses. Ranaviruses are double-stranded DNA viruses that cause hemorrhagic disease in amphibians, reptiles, and fish. They have caused mass die-offs of ectothermic vertebrates in wild and captive populations around the globe. There is evidence that this pathogen is emerging and responsible for population declines in certain locations. Considering that amphibians and freshwater turtles are suitable hosts and the most imperiled vertebrate taxa in the world, ranaviruses can have significant impacts on biodiversity and ecosystem function. Additionally, many fish that are raised in aquaculture facilities and traded internationally are suitable hosts; thus, the potential economic impact of ranaviruses is significant. Ranaviruses also serve as a model for replication and gene function of large double-stranded DNA viruses. There is an urgent need to assemble the contemporary information on ranaviruses and provide guidance on how to assess their threats in populations. Through the Global Ranavirus Consortium, 24 experts from six countries were organize to write this volume, the first book on ranaviruses. The book begins with a discussion on the global extent of ranaviruses, case histories of infection and disease in ectothermic vertebrates, and current phylogeny. Basic principles of ranavirus ecology and evolution are covered next, with a focus on host-pathogen interactions and how the virus emerges in its environment. There are two chapters that will discuss the molecular biology of ranaviruses, host response to infection, and the genes responsible for immune system evasion. One chapter establishes standards for testing for infection and diagnosing ranaviral disease. The book ends by providing guidance on how to design ranavirus surveillance studies and analyze data to determine risk, and discussing the role of the Global Ranavirus Consortium in organizing research and outreach activities.
Download or read book Post fire Treatment Monitoring of Critical Habitat for the California Red legged Frog Rana Aurora Draytonii and Unarmored Three spine Stickleback Gasterosteus Aculeatus Williamsoni in San Francisquito Canyon Following the Copper Fire written by Sara Compton and published by . This book was released on 2003 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Northern Red legged Frog Rana Aurora written by and published by . This book was released on 2015 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Radio Telemetric Study of the Movement Patterns of Adult Northern Red legged Frogs Rana Aurora Aurora at Freshwater Lagoon Humboldt County California written by Judy Ann Ganz Haggard and published by . This book was released on 2000 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Test of an Environmental Model written by James Bernard Bettaso and published by . This book was released on 2004 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book California Amphibian and Reptile Species of Special Concern written by Robert C. Thomson and published by Univ of California Press. This book was released on 2016-06-21 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important hotspots of herpetological biodiversity in the United States, California is home to many endemic amphibians and reptiles found nowhere else on earth. Many of these taxa have unique ecological and morphological specializations, and their management is an important conservation challenge. Increasing climate change impacts, human development, and extreme drought mean many of these species face an ever-greater risk of extinction. California Amphibian and Reptile Species of Special Concern provides an up-to-date synthesis of the current state of knowledge regarding the biology and conservation risks faced by 45 of California’s most sensitive amphibian and reptile species. With the goal of enhancing management based on the best available science, the authors developed a novel set of risk metrics to identify special concern species and the threats they face, including population declines, range size and restrictions, and ecological specializations and niche restrictions. In addition to detailed species accounts, this book provides a quantitative analysis of the conservation status and pressing management issues facing individual species and the state’s amphibian and reptile fauna as a whole. The volume focuses on identifying threats, concrete recommendations for management and recovery, and future research needs. The text is complemented by detailed distribution maps, color photos, and graphs. Written in nontechnical language, California Amphibian and Reptile Species of Special Concern will be a valuable resource to a broad range of users from resource managers, field biologists, and academic herpetologists to students and recreational naturalists. Published in association with the California Department of Fish and Wildlife.
Download or read book Conservation of California Red legged Frogs written by Antonia J. D'Amore and published by . This book was released on 2007 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
