Land of Extremes: A Natural History of the Arctic North Slope of Alaska - Softcover

Huryn, Alex; Hobbie, John

Softcover

ISBN 10: 1602231818 ISBN 13: 9781602231818

Verlag: Univ of Chicago behalf of UP Colorado, 2012

Inhaltsangabe

This book is a comprehensive guide to the natural history of the North Slope, the only arctic tundra in the United States. The first section provides detailed information on climate, geology, landforms, and ecology. The second provides a guide to the identification and natural history of the common animals and plants and a primer on the human prehistory of the region from the Pleistocene through the mid-twentieth century. The appendix provides the framework for a tour of the natural history features along the Dalton Highway, a road connecting the crest of the Brooks Range with Prudhoe Bay and the Arctic Ocean, and includes mile markers where travelers may safely pull off to view geologic formations, plants, birds, mammals, and fish. Featuring hundreds of illustrations that support the clear, authoritative text, Land of Extremes reveals the arctic tundra as an ecosystem teeming with life.

Über diesen Titel

Über die Autorin bzw. den Autor

Alexander Huryn is a freshwater ecologist and a committed field naturalist who has worked extensively in the Smoky Mountains, New Zealand, Panama, the Alaska Arctic, and Iceland. John Hobbie is a senior scholar at the Ecosystems Center, Marine Biological Laboratory in Woods Hole, Massachusetts. He is a founding researcher of the Toolik Field Station in Alaska and former director of the Arctic Long-Term Ecological Research Project there.

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LAND OF EXTREMES

A NATURAL HISTORY OF THE ARCTIC NORTH SLOPE OF ALASKABy Alexander D. Huryn John E. Hobbie

University of Alaska Press

Copyright © 2012 University of Alaska Press
All right reserved.
ISBN: 978-1-60223-181-8

Contents

Acknowledgments...........................................................................................xiiiPreface...................................................................................................xv1. Introduction...........................................................................................12. Bedrock Geology........................................................................................93. Glacial Geology........................................................................................174. Permafrost and Patterned Ground........................................................................235. Habitats and Ecology...................................................................................316. Mushroom Madness.......................................................................................537. Lichens................................................................................................578. Mosses and Liverworts..................................................................................639. Vascular Plants........................................................................................6710. Invertebrates.........................................................................................11311. Fish..................................................................................................15112. Reptiles and Amphibians...............................................................................16513. Birds.................................................................................................16714. Mammals...............................................................................................21115. Human Natural History Through the Mid-Twentieth Century...............................................243Appendix: Guide to Natural History Along the Dalton Highway: Atigun Pass to Deadhorse.....................255Endnotes..................................................................................................281Sources...................................................................................................287Index.....................................................................................................301

Chapter One

Introduction

The North Slope

The North Slope, also known as the Arctic Slope, is that part of northern Alaska where rivers drain into the Arctic Ocean north of Point Hope (Map 1). It is enormous, with an area equal to Nebraska or South Dakota (about 200,000 km²) and extending from about 68°N to 71°N at its greatest width. The North Slope contains three major physiographic regions: the Brooks Range, Arctic Foothills, and Arctic Coastal Plain. These are arranged as east–west trending bands parallel to the arctic coast, with the Arctic Coastal Plain most northerly and the Brooks Range most southerly. Each region has characteristic plant and animal communities due to differences in geology, topography, and climate. Nevertheless, they are all considered tundra. There are two types of tundra. Alpine tundra refers to mountain habitats above the tree line. Arctic tundra refers to habitats beyond the northern tree line. This book is an introduction to the natural history of the North Slope, the only arctic tundra in the United States.

Why the "Arctic"?

The Arctic is precisely defined as that part of the Northern Hemisphere where the sun is visible above the horizon for 24 hours during the summer solstice (around June 21) and is hidden below the horizon for 24 hours during the winter solstice (around December 22). The lowest latitude at which this occurs is about 66°33'N, which marks the position of the Arctic Circle and delimits the southern boundary of the Arctic. As one moves north from the Arctic Circle, the period of continuous daylight ("polar day") or darkness ("polar night") lengthens. At the southern North Slope village of Anaktuvuk Pass (68°8'N) in 2010, for example, the sun rose on May 25 and did not set again until July 18 (a 54-day polar day), while the polar day for the northern North Slope town of Barrow (71°17'N) lasted from May 11 to August 1 (82 days). Conversely, the polar night lasted from December 7, 2010, to January 4, 2011 (28 days), at Anaktuvuk Pass and from November 19, 2010, to January 21, 2011, at Barrow (63 days). Those unfamiliar with the relatively low arctic latitudes of the North Slope may have the impression that polar day and night are relatively constant periods of light and darkness. This is not so. During the polar day there are noticeable declines in light and temperature even on the summer solstice because the sun strikes the ground at a low angle during the early morning hours. During the polar night, even on the winter solstice, there is sufficient midday twilight to perform outdoor chores without a headlamp or lantern.

Having provided this pleasingly precise definition of the Arctic, it is important to point out its shortcomings. First, its precision is illusory. The Arctic Circle is not fixed but varies over about 2° during 40,000-year cycles caused by wobbles in the angle of the Earth's axis. Consequently, the location of the famous monument marking where the Dalton Highway crosses the Arctic Circle is only an approximation. Second, it does not adequately delimit the distribution of ecosystems containing communities of organisms adapted to arctic conditions. For example, no biologist would argue that the western shore of the Hudson Bay near Churchill, Manitoba, is not a typical arctic ecosystem, complete with polar bears, arctic foxes, and collared lemmings. Yet Churchill (58°45'N) is clearly south of the Arctic Circle and thus experiences no midnight sun. To accommodate such discrepancies, it has been suggested that the Arctic be defined to include areas of the Northern Hemisphere that have mean July temperatures of 10°C or less. The "10°C July mean-temperature rule" roughly determines the northern limit of tree growth and the southern limit of continuous permafrost. This definition is ecologically sound because it is based on a single key attribute that underlies the structure and function of all arctic communities: a long annual period of deep, dark cold.

Low Arctic versus High Arctic

The Arctic is often subdivided into the "high Arctic" and "low Arctic." The high Arctic includes habitats relatively close to the North Pole (e.g., greater than 75°N). With the exception of limited sedge meadows near streams and below lasting snowbanks, these are best characterized as rocky barrens populated by relatively few plant species (e.g., fewer than 150 vascular plant species). The low Arctic includes habitats closer to the Arctic Circle. These generally have comparatively lush vegetation and high plant diversity (more than 250 vascular plant species). Although all this may seem to be an exercise in hair splitting, it is important to be aware of the large differences between these subdivisions because much of what has been written about arctic ecosystems is based on the high Arctic and may not directly apply to the low Arctic. The North Slope, the focus of this book, provides an excellent example of a low-arctic ecosystem.

Climate

Temperature

The average annual...

Details zur Ausgabe

• Verlag: Univ of Chicago behalf of UP Colorado
• Erscheinungsdatum: 2012
• Sprache: Englisch
• ISBN 10: 1602231818
• ISBN 13: 9781602231818
• Einband: Taschenbuch
• Anzahl der Seiten: 311
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: gpsr@libri.de; gpsr@libri.de; ; Friedensallee 273; Hamburg; 22763; Deutschland