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Filtering by: Creator Peterson, Eric T. Remove constraint Creator: Peterson, Eric T. Advisor Blaustein, Andrew R. Remove constraint Advisor: Blaustein, Andrew R.

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  • Unpalatability as an antipredator defense in anuran larvae

    Creator:
    Peterson, Jeffrey A.
    Abstract:
    The tadpoles of several anuran species with groupforming larvae are relatively unpalatable to many of their potential predators. To more fully understand the role of palatability and its relationship to group formation as an antipredator defense in anuran amphibian larvae, I investigated the palatabilities of the larvae of three species...
    Resource Type:
    Masters Thesis
    Full Text:
    AN ABSTRACT OF THE THESIS OF Jeffrey A. Peterson for the degree of Master of Science in Zoology

  • Host-pathogen dynamics in a changing environment : susceptibility of amphibians to an emerging infectious disease

    Creator:
    Searle, Catherine L.
    Abstract:
    Infectious diseases are a growing concern for both humans and wildlife. The negative effects of infectious disease have been exemplified by the recent global amphibian population declines associated with disease outbreaks. Although multiple pathogens and factors play a role in these declines, the aquatic fungal pathogen, Batrachochytrium dendrobatidis (Bd), has...
    Resource Type:
    Dissertation
    Full Text:
    . 2006, Peterson et al. 2009). Corticosterone can be artificially elevated in larval amphibians by

  • Kin recognition in Townsend's chipmunks (Tamias townsendii)

    Creator:
    Fuller, Claire A.
    Abstract:
    Juvenile T. townsendii were tested at 55-62 days of age to determine whether 1) they could distinguish kin from non-kin and 2) whether this ability was based on familiarity or on genetic relatedness. Seventy-three pups were observed in 68 pairwise tests. The frequencies and durations of 8 behaviors as well...
    Resource Type:
    Masters Thesis
    Full Text:
    ) Abstract approved:_Redacted for Privacy__ Andrew R. Blaustein Juvenile T. townsendii were tested at 55-62

  • The effects of predation on anuran metamorphosis

    Creator:
    DeVito, Jill
    Abstract:
    Many organisms with complex life cycles undergo transition periods associated with increased vulnerability to predation. Several evolutionary adaptations have been proposed as antipredator defenses for organisms during risky transition periods. These include: shortening of the transition period, parental care, cryptic coloration, and synchrony of risky transitions with large numbers of...
    Resource Type:
    Masters Thesis
    Full Text:
    larval environment. Since the Pacific treefrog (Hy la regilla) is also preyed upon by T. sirtalis

  • Experimental analysis of competition between desert rodents in Oregon

    Creator:
    Schoffelen, Emile
    Resource Type:
    Masters Thesis
    Full Text:
    Lahanas, Cindy Lee, Connie Rinaldo, Eric Sandberg and Vicki Schaaf. Funding was provided by a grant in

  • Indirect effects of ultraviolet-B radiation on larval amphibians as mediated by food quality and trophic interactions

    Creator:
    Scheessele, Erin A.
    Abstract:
    Ultraviolet-B radiation (UVB) is an abiotic stressor in both terrestrial and aquatic systems. The stratospheric ozone layer, depleted due to anthropogenic activities and the cause of elevated UVB at earth's surface over the last four decades, is predicted to recover by 2065. However, UVB levels in aquatic systems may continue...
    Resource Type:
    Dissertation
    Full Text:
    psychological health as a graduate student. Eric Seabloom introduced me to von Ende & profile analysis, which

  • The effects of parasites on host behavior : who benefits?

    Creator:
    Lefcort, Hugh G.
    Abstract:
    Some parasites may modify the behavior of their hosts. Altered behaviors may: 1) benefit the host in that they defend against the pathogen, 2) benefit the pathogen and represent manipulations of the host response, and 3) benefit neither the host or the pathogen and simply be a product of the...
    Resource Type:
    Dissertation
    Full Text:
    not appear on my graduate committee, it should. Eric Berlow has been a constant sounding board for

  • The effects of multiple pathogens on amphibians in the Pacific Northwest

    Creator:
    Romansic, John M.
    Abstract:
    The earth is undergoing a “biodiversity crisis” characterized by loss of populations, species, genetic diversity, and ecosystem services. Part of this crisis consists of population declines, extinctions, and increased incidence of deformities in amphibians. It is unknown whether deformities contribute to these declines. Many cases of population declines in amphibians...
    Resource Type:
    Dissertation
    Full Text:
    Krenz, Roly Russell, Luis Vinueza, Joe Tyburczy, Michael Westphal, and Eric Seabloom were particularly

  • Ultraviolet radiation as an environmental stressor of amphibians

    Creator:
    Bancroft, Betsy A.
    Abstract:
    My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial and aquatic systems. I used meta-analysis to quantify the effects of UVB radiation on a diversity of aquatic organisms (Chapter 2). UVB...
    Resource Type:
    Dissertation
    Full Text:
    portions of this thesis and provided much needed help with meta-analysis techniques. Eric Seabloom

  • Toad Populations Decreasing in South Korea

    Creator:
    Chung, Yun Soo
    Abstract:
    Massive die-offs of Bufo bufo gargarizans were observed in May 2008 in Mangwal Gee, Korea. To find out the causes for this disaster several different elements were examined: pH, total nitrogen, dissolved oxygen (DO), and dissolved heavy metal, suspension, introduced species, habitat change, disease, temperature changes, and precipitation and humidity....
    Resource Type:
    Honors College Thesis
    Full Text:
    species in the Pond-------------------------------------------- 12 6. emperature T al

  • Disentangling the Biotic and Abiotic Drivers of the Amphibian Disease Chytridiomycosis

    Creator:
    Bradley, Paul W.
    Abstract:
    The ongoing worldwide loss of biodiversity has been described as a "biodiversity crisis," "the Anthropocene defaunation," and alternatively "an extinction spasm." More recently, many scientists have come to the conclusion that we are witnesses to Earth's sixth major mass extinction event, which has the potential to fundamentally alter basic ecological...
    Resource Type:
    Dissertation
    Full Text:
    al. 1999; Peterson et al. 2013). Evidence suggests that host mortality is caused by the

  • All hosts are not created equal : variation in amphibian responses to an emerging fungal pathogen and why it matters

    Creator:
    Gervasi, Stephanie S.
    Abstract:
    Emerging infectious diseases are increasing globally and are a threat to human, wildlife, and ecosystem health. The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), or amphibian chytrid fungus, is associated with worldwide amphibian population declines and extinctions. Bd has been found on every continent where amphibians exist and has been documented...
    Resource Type:
    Dissertation
    Full Text:
    pathogen-specific responses that may be cellular (e.g. generation of various subsets of T-lymphocytes) or

  • The Effects of Host and Pathogen Variation on Infection Dynamics in the Amphibian-Chytrid System

    Creator:
    Dang, Trang D.
    Abstract:
    This dissertation uses manipulative experiments to explore amphibian-Bd infection dynamics. Although there has been almost two decades research since the discovery of Bd, many questions still remain regarding what conditions mediate chytridiomycosis virulence. My research shows how certain host and pathogen factors can influence disease virulence. Identifying how host and...
    Resource Type:
    Dissertation
    Full Text:
    , M. C., Garner, T. W. J. and Li, Y. (2012). Global and endemic Asian lineages of the emerging

  • The effects of an emerging pathogen on amphibian host behaviors and interactions

    Creator:
    Han, Barbara A.
    Abstract:
    Contemporary environmental change encompasses massive biodiversity loss and increasing numbers of emerging diseases worldwide. As part of a global biodiversity crisis, amphibians are disappearing at unprecedented rates. Batrachochytrium dendrobatidis is an emerging infectious pathogen prominently associated with many declines. Chapter 1 reviews the past decade of research on this system...
    Resource Type:
    Dissertation
    Full Text:
    severe BD infections by creating an inhospitable environment for BD growth and reproduction (Peterson

  • The Behavioral Responses of Western Toad (Anaxyrus boreas) Larvae to Simultaneous Stressors

    Creator:
    Reynolds, Emily R.
    Abstract:
    Animals can be naturally exposed simultaneously to multiple stressors. These include habitat changes, contaminants, diseases, invasive species, parasitism, and predation. Exposure to various combinations of biotic and abiotic stressors may induce behavioral changes that affect the way an individual interacts within its environment.Like other groups of organisms, amphibians are exposed...
    Resource Type:
    Masters Thesis
    Full Text:
    -sample t-tests to compare overall treatment effects on avoidance and activity behaviors

  • Ecological aspects of kin discriminating behavior with implications of functional value

    Creator:
    Hokit, D. Grant
    Abstract:
    To assess the context dependence of kin discriminating behavior, I examined kin-biased aggregation behavior in tadpoles of R. cascadae in different ecological conditions. I manipulated food distribution, predator presence, thermal heterogeneity, and relatedness in a multifactorial mesocosm experiment. All four factors interacted to influence tadpole dispersion. My results suggest that...
    Resource Type:
    Dissertation
    Full Text:
    major Chair o epaff t o oology Dean of Grad ---CISchoI:t------- Date thesis is presented August 18

  • The Role of Emerging Pathogens in Amphibian Population Declines : Experimental Evidence

    Creator:
    Hambalek, Natalie M.
    Abstract:
    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...
    Resource Type:
    Masters Thesis
    Full Text:
    and inoculation for Chapter 3. Jason T. Hoverman offered perspective to Chapters 2 and 3 and

  • Cannibalism in larvae of the long-toed salamander, Ambystoma macrodactylum

    Creator:
    Wildy, Erica Lynn
    Abstract:
    Predator-prey interactions have historically been studied to explain patterns of organization observed in populations and communities. They have also been important in understanding the evolution of antipredator responses in prey and counterstrategies in predators. Despite the breadth of knowledge that exists for heterospecific interactions, relatively few studies have investigated the...
    Resource Type:
    Dissertation
    Full Text:
    Eric Hoffman for their academic as well as social support. I would like to acknowledge the members of

  • The Effects of Nitrate and a Pathogenic Fungus, Batrachochytrium dendrobatidis, on Amphibians

    Creator:
    Negru, Delia
    Abstract:
    The current rate of global biodiversity loss and extinctions is unparalleled and a major concern. Freshwater organisms are facing particularly rapid rates of biodiversity loss. Amphibians, which require an aquatic environment for part of their life cycle, are one of the most vulnerable vertebrate groups. Amphibians are experiencing population declines,...
    Resource Type:
    Masters Thesis
    Full Text:
    . Ecology 86(12):3149-3159. Brühl CA, Schmidt T, Pieper S, Alscher A. 2013. Terrestrial pesticide

  • Host parasite relationships between deer mice (Peromyscus maniculatus) and their eimerian parasites (protozoa)

    Creator:
    Fuller, Claire A.
    Resource Type:
    Dissertation
    Full Text:
    O'Hara, Dede Olson, Jeff Peterson and Susan Walls were always interesting. Finally, I would like to

  • Environmental influences on host-pathogen dynamics of the amphibian chytrid fungus

    Creator:
    Buck, Julia C.
    Abstract:
    The causes of the global biodiversity crisis are varied and complex. Anthropogenic threats may act in isolation, or interact additively or synergistically with each other or with natural stressors to affect sensitive taxa. The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease...
    Resource Type:
    Dissertation

  • Multiple stressors and amphibian population declines

    Creator:
    Hatch, Audrey C.
    Abstract:
    In the past decade, declines in amphibian populations have captured scientific and popular interest. The causes of the declines are likely to be complex and involve interactions between several environmental stressors. Using multifactorial experiments, I investigated the combined effects of several anthropogenic stressors on developing amphibians in Oregon, USA. In...
    Resource Type:
    Dissertation
    Full Text:
    , Wendy Walker, Mario Ambrosino, Pat Moran, Dr. Jennifer Peterson, Dr. Jennifer Gervais, Christopher