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Filtering by: Creator Nussbaum, Ronald A. Remove constraint Creator: Nussbaum, Ronald A. Advisor Blaustein, Andrew R. Remove constraint Advisor: Blaustein, Andrew R. Degree Field Zoology Remove constraint Degree Field: Zoology

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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

  • 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:
    DISSERTATION OF Erin A. Scheessele for the degree of Doctor of Philosophy in Zoology presented on November

  • 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:
    : ________________________________________________________ Andrew R. Blaustein The earth is undergoing a “biodiversity crisis” characterized by

  • 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:
    24, 2016. Title: The Effects of Nitrate and a Pathogenic Fungus, Batrachochytrium dendrobatidis

  • 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:
    presence, thermal heterogeneity, and relatedness in a multifactorial mesocosm experiment. All four

  • The effects of pathogens, UV-B radiation, and introduced species on amphibians in the Pacific Northwest

    Creator:
    Kiesecker, Joseph Michael
    Abstract:
    I examined two amphibian communities to assess factors that may impact amphibian biodiversity. The results suggest that the potential factors which influence the maintenance of amphibian biodiversity are multi-faceted and thus, attempts to understand these factors must reflect these complexities. I investigated factors that influenced the susceptibility of western toad...
    Resource Type:
    Dissertation
    Full Text:
    al. 1993). The red-legged frog, Rana aurora, a once abundant species (Stebbins 1985, Nussbaum et

  • 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:
    absence of a live snake predator, the common garter snake (Thamnophis sirtalis) in a laboratory

  • An investigation of the alarm response in anuran amphibian larvae

    Creator:
    Hews, Diana K.
    Abstract:
    The results of my research suggest that tadpoles of the Western toad (Bufo boreas) and the Cascades frog (Rana cascadae) display an alarm response to chemicals from injured conspecific tadpoles. Furthermore, results suggest that the Bufo boreas alarm response can be elicited by a natural predator when it feeds on...
    Resource Type:
    Masters Thesis
    Full Text:
    Bufo boreas alarm response can be elicited by a natural predator when it feeds on a conspecific

  • 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:
    widely documented within a diversity of animal groups including amphibians. In this thesis, I offer

  • 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:
    privacy regilla, I found that UV-B and nitrate together had a negative effect on larval mass in the