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Ecology And Man In Mexico S Central Volcanoes Area

Author: G.W. Heil
Publisher: Springer Science & Business Media
ISBN: 9400709692
Size: 53.26 MB
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The main activities of the economically active population around The Iztaccíhuatl and Popocatépetl volcanoes region lie in the primary sector (65- 90%). Of the people working in this sector, those dependent on agricultural or pastoral activities generally have an income significantly lower than the minimum wage in Mexico. Of the activities in the area, these agricultural, pastoral, and forestry activities probably have the most direct effect on the ecology of the volcanoes and its immediate surroundings. Traditional farmers, producing crops such as beans, pumpkins and cucumbers, generally work on small fields using traditional methods and animal traction. Modern farming, geared towards intensive production develops on larger sites making use of modern machinery, fertilizers, and pesticides. As the area under agriculture continues to increase every year, the attendant opening of large forested areas, soil modification, and ensuing erosion make it almost impossible for forest recovery. Extensive forestry in the region mainly concerns cutting and collecting wood, cutting Pinus-branches for torches or for utensils for open-fire cooking, collection of mushrooms, and hunting. Although these (often clandestine) activities seem to be small-scale, their adverse effects on the forest have been substantial. Weekend visitors from Mexico City heavily dominate recreation, with tourism concentrated near the roads leading to and inside the park. Lacking organization and facilities, most recreational activities have had significant environmental impact on the area In many countries, the decline of nature has occurred because of changes in land use.

Essay On The Geography Of Plants

Author: Alexander von Humboldt
Publisher: University of Chicago Press
ISBN: 0226360687
Size: 50.45 MB
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The legacy of Alexander von Humboldt (1769–1859) looms large over the natural sciences. His 1799–1804 research expedition to Central and South America with botanist Aimé Bonpland set the course for the great scientific surveys of the nineteenth century, and inspired such essayists and artists as Emerson, Goethe, Thoreau, Poe, and Church. The chronicles of the expedition were published in Paris after Humboldt’s return, and first among them was the 1807 “Essay on the Geography of Plants.” Among the most cited writings in natural history, after the works of Darwin and Wallace, this work appears here for the first time in a complete English-language translation. Covering far more than its title implies, it represents the first articulation of an integrative “science of the earth, ” encompassing most of today’s environmental sciences. Ecologist Stephen T. Jackson introduces the treatise and explains its enduring significance two centuries after its publication.

The Invention Of Nature

Author: Andrea Wulf
Publisher: Vintage
ISBN: 0345806298
Size: 12.59 MB
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A portrait of the German naturalist reveals his ongoing influence on humanity's relationship with the natural world today, discussing such topics as his views on climate change, conservation, and nature as a resource for all life.

Caldera Volcanism

Author: Joachim Gottsmann
Publisher: Elsevier
ISBN: 0080558976
Size: 69.76 MB
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This volume aims at providing answers to some puzzling questions concerning the formation and the behavior of collapse calderas by exploring our current understanding of these complex geological processes. Addressed are problems such as: - How do collapse calderas form? - What are the conditions to create fractures and slip along them to initiate caldera collapse and when are these conditions fulfilled? - How do these conditions relate to explosive volcanism? - Most products of large caldera-forming eruptions show evidence for pre-eruptive reheating. Is this a pre-requisite to produce large volume eruptions and large calderas? - What are the time-scales behind caldera processes? - How long does it take magma to reach conditions ripe enough to generate a caldera-forming eruption? - What is the mechanical behavior of magma chamber walls during caldera collapse? Elastic, viscoelastic, or rigid? - Do calderas form by underpressure following a certain level of magma withdrawal from a reservoir, or by magma chamber loading due to deep doming (underplating), or both? - How to interpret unrest signals in active caldera systems? - How can we use information from caldera monitoring to forecast volcanic phenomena? In the form of 14 contributions from various disciplines this book samples the state-of-the-art of caldera studies and identifies still unresolved key issues that need dedicated cross-boundary and multidisciplinary efforts in the years to come. * International contributions from leading experts * Updates and informs on all the latest developments * Highlights hot topic areas and identifies and analyzes unresolved key issues