879 resultados para important memories
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Goose grazing on arctic tundra vegetation has shown both positive and negative effects on subsequent foraging conditions. To understand the potential of a density-dependent feedback on herbivore population size, the relation between grazing pressure and future foraging conditions is essential. We studied the effect of increasing grazing pressure of barnacle geese (Branta leucopsis) on Spitsbergen. During the establishment of a breeding colony in the period 1992-2004, the proportion of graminoids decreased in the diet of wild geese, while the percentage of mosses increased. Grazing trials with captive geese in an unexploited area showed a similar shift in diet composition. High-quality food plants were depleted within years and over years. Intake rate declined too and as consequence, metabolisable energy intake rate (MEIR) decreased rapidly with increasing grazing pressure. During three successive years of experimental grazing, MEIR decreased at all levels of grazing pressure and declined below minimal energetic requirements when grazing exceeded natural levels of grazing pressure. This suggests that foraging conditions rapidly decline with increasing grazing pressure in these low-productive habitats. The potential for density-dependent feedbacks on local population increase is discussed.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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v. 1. Essay on the connexion between the doctrine of justification by the imputed righteousness of Christ, and holiness of life. The absolute necessity of salvation through Christ. The trial of religious truth by its moral influence. The charge of sedition and faction against good men, especially faithful ministers, considered and accounted for. Prayer for national prosperity and for the revival of religion inseparably connected -- v. 2. A serious enquiry into the nature and effects of the stage. Ecclesiastical characteristics -- v. 3. A practical treatise on regeneration.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Half title in English and Japanese.