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Filtering by: Creator Oeffner, Scott P. Remove constraint Creator: Oeffner, Scott P. Contributor advisor sim Blaustein, Andrew R. Remove constraint Contributor advisor sim: Blaustein, Andrew R.

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  • 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:
    . Growth and development of R. cascadae did not differ between a UVB-exposed and UVB-shielded diet, but P

  • 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:
    significantly reduced survival in P. regilla, and treatments with both high and low nitrate and Bd

  • Effects of Diversity on Emerging Infectious Diseases of Amphibians

    Creator:
    Snyder, Paul W.
    Abstract:
    Species declines and extinctions have been recorded across taxa as evidence of an ongoing global biodiversity crisis. Amphibians are at the forefront of these declines with nearly one third of amphibian species estimated to be at risk of extinction. While many factors contribute to population declines and extinctions, the role...
    Resource Type:
    Dissertation
    Full Text:
    the presence of P. regilla amphibian assemblages experienced nearly complete mortality of all

  • 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:
    tadpoles. Overall, exposure to UVB reduced survival of P. regilla larvae and reduced growth of R

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

    Creator:
    Fuller, Claire A.
    Resource Type:
    Dissertation
    Full Text:
    1991, Scott & Dobson 1989, Scott & Lewis 1987). However, many factors differ between the

  • Ontogenetic Shifts in Disease Response in Native and Invasive Anuran Species

    Creator:
    Urbina Gonzalez, Jenny Cecilia
    Abstract:
    This dissertation presents a different approach to understanding how amphibians are responding to disease through ontogeny. Although numerous efforts have been conducted to understand host responses to the fungus Batrachochytrium dendrobatidis (Bd), studies have been restricted to distinct developmental stages. This dissertation provides information on host response to Bd across...
    Resource Type:
    Dissertation
    Full Text:
    . .............................................................................................. 33 Figure 2.2 Proportion of hatchlings in P. regilla (top), A. boreas (middle), and L

  • 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:
    , May and Anderson 1979, Scott and Anderson 1984, Price et al. 1986, Scott 1987, Price et al. 1988

  • 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:
    snout-vent-length and mass measurements……………………… 76 3.2 Hazard ratios and associated p-values

  • 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:
    Violin plot (with boxplot overlay) of Bd infection intensity A) P. regilla, B) A. boreas, and C) R

  • 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:
    R. cascadae and P. regilla in the Oregon Cascades Range, apparently by mediating density of larvae