Bøger af Virginia H. Dale

Recon?guring Disturbance, Succession, and Forest Management: The Science of Mount St. Helens When Mount St. Helens erupted on May 18, 1980, it did more than just recon?gure a large piece of Cascadian landscape. It also led to dramatic revisions in our perspectives on disturbances, secondary succession, and forestry practices. The Mount St. Helens landscape turned out to be a far more complex place than the "e;moonscape"e; that it initially appeared to be. Granted, a large area was literally scoured and sterilized, and that vast expanse of newly formed rock, mud?ows, and avalanche debris up and down the mountain made the Mount St. Helens landscape unique. But I still remember my surprise when, as I stepped out of the helicopter on ?rst landing within the extensive "e;devastated zone,"e; I saw hundreds of plants pushing their way up through the mantel of tephra. Surviving organisms were stunning in their diversity, abundance, and the mechanisms by which they survived. They persisted as whole organisms living below ground, encased within late-persisting snowbanks, and buried in lake and stream sediments. They survived as rhizomes transported along with the massive landslide that accompanied the eruption and as stems that suffered the abrasion of mud?ows. Mud?ows ?oated nurse logs covered with tree seedlings and then redeposited them on the ?oor of a forested river terrace. Millions, perhaps billions, of plants survived as rootstocks and rhizomes that pushed their way up through the tephra, and others survived on the bases of uprooted trees.

A central goal of transportation is the delivery of safe and efficiservices with minimal environmental impact. In practice, though, human mobility has flourished while nature has suffered. Awareness of the environmental impacts of roads is increasing, yet information remains scarce for those interested in studying, understanding, or minimizing the ecological effects of roads and vehicles. Road Ecology addresses that shortcoming by elevating previously localized and fragmented knowledge into a broad and inclusive framework for understanding and developing solutions. The book brings together fourteen leading ecologists and transportation experts to articulate state-of-the-science road ecology principles, and presents specific examples that demonstrate the application of those principles. Diverse theories, concepts, and models in the new field of road ecology are integrated to establish a coherframework for transportation policy, planning, and projects. Topics examined include: *foundations of road ecology *roads, vehicles, and transportation planning *vegetation and roadsides *wildlife populations and mitigation *water, sediment, and chemical flows *aquatic ecosystems *wind, noise, and atmospheric effects *road networks and landscape fragmentationRoad Ecology links ecological theories and concepts with transportation planning, engineering, and travel behavior. With more than 100 illustrations and examples from around the world, it is an indispensable and pioneering work for anyone involved with transportation, including practitioners and planners in state and province transportation departments, federal agencies, and nongovernmental organizations. The book also opens up an important new research frontier for ecologists.

Examines scientific advances since 2000 that may have increased understanding and options in three general areas related to hypoxia: Characterization, the Cause(s) of Hypoxia; Characterization of Nutrient Fate, Transport and Sources; and, Scientific Basis for Goals and Management Options.