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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A study of the Coprophilous Ascomycetes of Utah

Hanks, David L. 01 May 1963 (has links)
Specimens of animal dung were collected from various areas of the state of Utah. These were cultured by placing a few small pieces in a culture dish over moistened sphagnum moss and filter paper. The cultures were observed periodically and specimens were studied as they matured upon the substratum. A total of eighty-four species representing three orders and fifteen genera are reported. Of these, nine species have not previously been described. Included is one species, Tripterospora erostrata, from the order Plectascales of the Series Plectomyceteae. Cited from the order Sphaeriales of the Series Pyrenomyceteae are forty-nine species as follow: Coniochaeta, two species; Delitschia, nine species; Hypocopra, two species; Pleophragmia, two unnamed species; Sordaria, thirteen species; and Zygospermella, one species. From the order Pezizles of the Series Discomyceteae are reported thirty-four species as follows: Ascobolus, five species, including one unnamed species; Ascophanus, thirteen species; Cheilymenia, four species; Peziza, three species; Lasiobols, two species, one unnamed species; and Saccobolus, five species, two of which are reported for the first time.
2

Apports des microfossiles non-polliniques à l'histoire du pastoralisme sur le versant nord Pyrénéen : entre référentiels actuels et reconstitution du passé / The use of non-pollen palynomorphs for reconstructing the history of pastoral activities in the Pyrenees : from modern datasets to reconstruction of the past

Cugny, Carole 27 September 2011 (has links)
Les microfossiles non-polliniques, des restes de divers organismes préservés dans les sédiments lacustres ou tourbeux, sont de plus en plus couramment employés en paléoécologie. Parmi ces microrestes, les spores de champignons coprophiles sont privilégiées dans les reconstructions des activités humaines telles que les activités pastorales. L’aptitude de ces spores à refléter la présence ou l’abondance des troupeaux n’est pas encore complètement comprise. Des analogues modernes ont été collectés dans deux zones d’estive, dans les montagnes du Pays Basque et d’Ossau. Des analyses de gradients contraintes par des variables environnementales ont permis d’identifier des assemblages non-polliniques associés à diverses conditions environnementales en contexte humide et terrestre. Un cortège d’ascospores de groupes coprophiles liées aux activités pastorales a pu être isolé. Les référentiels ont également fourni des informations sur la portée spatiale de l’information non-pollinique.Les microfossiles non-polliniques ont été étudiés dans quatre séquences tourbeuses en complément d’autres sources d’informations paléoenvironnementales (pollen, signal incendie). Ils ont fourni les informations sur les dynamiques des quatre sites durant l’Holocène et les périodes historiques. Les résultats des référentiels sont appliqués à l’interprétation des dynamiques pastorales. Les résultats modernes et fossiles montrent que la charge pastorale n’est pas le seul paramètre qui influence les signaux coprophiles ; ces spores pourraient avoir un potentiel d’indicateurs paléoenvironnementaux et pastoraux plus étendu qu’attendu.Les ascospores de groupes coprophiles sont décrites et illustrées ainsi que d’autres microfossiles fongiques, algaux et indéterminés. / Non-pollen palynomorphs, microscopic remains produced by a variety of organisms and preserved in peat and lake sediments, are now more widely used in palaeoenvironmental studies. In particular, spores of coprophilous fungi are considered as an adapted tool to reconstruct past land-use such as pastoral activities. However, their ability to reflect the presence and/or the number of cattle is not fully understood yet. Modern analogs from summer pastures in the Basque Mountains and the Ossau valley have been collected. Numerical analysis of modern non pollen-palynomorphs and environmental variables helped to distinguish several pools of microremains associated to distinct environmental conditions in both terrestrial and wet ecosystems. A group of ascospores of dung-related fungi clearly related to grazing activities was isolated. The modern dataset also provided useful information on the spatial scale represented by non-pollen palynomorphs. Fossil non-pollen palynomorphs from four peat records, combined with other palaeoenvironmental data (pollen, fire frequencies), have been studied. They informed on the evolution of the local conditions of the wetlands during Holocene and historical times. The modern data set is used to aid interpretation of the dynamics of past land-use and pastoral activities. The results from both modern and fossil approaches show that other parameters than the grazing pressure can induce variability in the copropilous signals; the indicative value of dung-related ascospores might be broader than expected. The ascospores of dung-related taxa are described and illustrated, alongside with other fungal, algal and unidentified microremains.

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