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Filtering by: Creator DeVault, Travis L. Remove constraint Creator: DeVault, Travis L. Degree Field Zoology Remove constraint Degree Field: Zoology

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  • The influence of biophysical feedbacks and species interactions on grass invasions and coastal dune morphology in the Pacific Northwest, USA

    Creator:
    Zarnetske, Phoebe Lehmann
    Abstract:
    Biological invasions provide a unique opportunity to study the mechanisms that regulate community composition and ecosystem function. Invasive species that are also ecosystem engineers can substantially alter physical features in an environment, and this can lead to cascading effects on the biological community. Aquatic-terrestrial interface ecosystems are excellent systems to...
    Resource Type:
    Dissertation
    Full Text:
    , Elymus mollis (Trin.), and two non-natives, Ammophila arenaria (L.) Link and A. breviligulata Fernald

  • Cardiac and respiratory responses to hypoxia in the crab, Cancer magister (Dana)

    Creator:
    Stiffler, Daniel Francis
    Abstract:
    Heart rates and amplitudes were measured for both intact animals (in situ) and isolated hearts (in vitro) of the Dungeness crab, Cancer magister, exposed to low levels in oxygen. Recordings were also made of gill ventilation rate by measuring the frequency of scaphognathite (gill bailer) beats. Both the in vitro...
    Resource Type:
    Masters Thesis
    Full Text:
    was reported in Limulus polyphemus, a xiphosuran, by Hyde (1906, cited by Waterman and Travis, 1953

  • 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:
    offered to L. americanus larvae. 15 Experiment 8: mid-developmental tadpoles offered to L. americanus

  • Dogs, Death, and Dietary Breadth: Insights into the Macroecology and Macroevolution of Canidae

    Creator:
    Tanis, Brian P.
    Abstract:
    The size, shape, and stability of a species’ dietary niche can both influence and reflect a variety of biological patterns, including species interactions, extinction risk, and ecosystem function. This is particularly apparent when dietary changes manifest at ecosystem and clade scales to profoundly affect macroecological and macroevolutionary trajectories. However, many...
    Resource Type:
    Dissertation

  • 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:
    laboratory where they were placed into aerated 38 L aquaria filled with dechlorinated tap water. Egg masses

  • Variation in female reproductive success in amphibians

    Creator:
    Dyal, Leslie A.
    Abstract:
    My dissertation focuses on the factors that influence variation in female reproductive success in plethodontid salamanders and in toads. Variation in reproductive success fuels evolutionary change. Although, females often have been overlooked in studies of reproductive success due to perceived lower levels of variation when compared to variation in male...
    Resource Type:
    Dissertation

  • Oxygen uptake of tissue from normal and destalked crayfish

    Creator:
    Turner, Lewis McDonald
    Resource Type:
    Masters Thesis
    Full Text:
    leve l of oxygen con­ sumption in nine crustacean decapods which ranged from marine aquatic to

  • Natural history and evolution of a color polymorphism in Rana pipiens, the northern leopard frog

    Creator:
    Hoffman, Eric A.
    Abstract:
    A primary goal of population genetics is to identify the role of microevolutionary forces in producing observed patterns of molecular and phenotypic variation. I conducted four studies in the northern leopard frog, Rana pipiens, to determine just how mutation, migration, genetic drift, and selection influenced, genetic structure of mitochondrial DNA...
    Resource Type:
    Dissertation
    Full Text:
    population was used (L=large spatial area, S=small spatial area, T=temporal variation), number of samples per

  • 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:
    2001, Dunson and Travis 1991). iNTERACTIONS OF ABIOTIC STRESSORS Introduction Several studies of

  • 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:
    with nylon mesh screen, filled them with approximately 5 L dechlorinated tap water, and covered