نتایج جستجو برای: amphibians
تعداد نتایج: 7922 فیلتر نتایج به سال:
An examination of amphibian sensitivity to environmental contaminants: are amphibians poor canaries?
Nearly two decades ago, the global biodiversity crisis was catapulted to the front pages of newspapers with the recognition of worldwide amphibian declines. Amphibians earned their appellation, 'canaries in a coal mine', because of apparent high sensitivity to human-mediated environmental change. The most frequently cited causes for high susceptibility include permeable skin, a dual aquatic-ter...
—Numerous anthropogenic and natural factors affect living organisms in nature. Anthropogenic factors include a wide array of contaminants and processes that alter the habitat on both local and global scales. For example, chlorofluorocarbons (CFCs) and other industrial gases contribute to the depletion of the earth’s protective ozone layer, resulting in increased amounts of cell damaging ultravi...
The present study examines amphibian metabolic activity - particularly conjugation - by analysis of pyrene (a four ring, polycyclic aromatic hydrocarbon) metabolites using high-performance liquid chromatography (HPLC) with fluorescence detector (FD), a mass spectrometry detector (MS) system and kinetic analysis of conjugation enzymes. Six amphibian species were exposed to pyrene (dissolved in w...
The amphibian epidermis presents many barriers that prevent pathogen infection. Much effort has been placed on examining determinants of infectivity and pathogenicity of Batrachochytrium dendrobatidis (Bd) in amphibians. However, no research has examined how trauma to the epidermis can affect susceptibility to and virulence of Bd infections in amphibians. Trauma is a common entry point for seco...
1. Amphibians are recognized both for their sensitivity to environmental perturbations and for their usefulness as cost-effective biometrics of ecosystem integrity (=system health). 2. Twenty-three years of research in headwater streams in the Klamath-Siskiyou and North Coast Bioregions of the Pacific Northwest, U.S.A., showed distinct patterns in the distribution of amphibians to variations in...
Considerable progress has been made in understanding the responses of amphibians to climate change, with successful research carried out on climate change-associated shifts in amphibian phenology, elevational distributions and amphibian-parasite interactions. We review and synthesize the literature on this topic, emphasizing acutely lethal, sublethal, indirect and positive effects of climate ch...
Amphibians are a globally distributed and diverse lineage, but much of our current understanding of their population genetic structure comes from studies in mesic temperate habitats. We characterize the population genetic structure of two sympatric explosive breeding amphibians in the southwestern deserts of the United States: the Great Plains toad (Anaxyrus cognatus) and Couch's spadefoot toad...
Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to...
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