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Regional vegetation die-off in response to global-change-type drought

    Resource Identifier: http://www.pnas.org/content/102/42/15144.full
    Cataloging Node: Gap Analysis Program
    Creator: David D. Breshears
    Contributor: Neil S. Cobb, Paul M. Rich, Kevin P. Price, Craig D. Allen, Randy G. Balice, William H. Romme, Jude H. Kastensf, M. Lisa Floyd, Jayne Belnap.Jesse J. Anderson, Orrin B. Myersn, and Clifton W. Meyer
    Subject: Gap analysis
    Uncontrolled Keywords: * tree mortality * vegetation dynamics * climate change impacts * woodlands * Pinus edulis, drought, Pinus Edulis
    Scientifc Names: Pinus Edulis
    Common Names: colorado pinyon, nut pine, Pi±=n de Colorado, pinon pine, pinyon, Pinyon pine, two-leaf pinyon, two-needle pinyon, twoneedle pinyon
    Description: Future drought is projected to occur under warmer temperature conditions as climate change progresses, referred to here as global-change-type drought, yet quantitative assessments of the triggers and potential extent of drought-induced vegetation die-off remain pivotal uncertainties in assessing climate-change impacts. Of particular concern is regional-scale mortality of overstory trees, which rapidly alters ecosystem type, associated ecosystem properties, and land surface conditions for decades. Here, we quantify regional-scale vegetation die-off across southwestern North American woodlands in 2002-2003 in response to drought and associated bark beetle infestations. At an intensively studied site within the region, we quantified that after 15 months of depleted soil water content, >90% of the dominant, overstory tree species (Pinus edulis, a piñon) died. The die-off was reflected in changes in a remotely sensed index of vegetation greenness (Normalized Difference Vegetation Index), not only at the intensively studied site but also across the region, extending over 12,000 km2 or more; aerial and field surveys confirmed the general extent of the die-off. Notably, the recent drought was warmer than the previous subcontinental drought of the 1950s. The limited, available observations suggest that die-off from the recent drought was more extensive than that from the previous drought, extending into wetter sites within the tree species' distribution. Our results quantify a trigger leading to rapid, drought-induced die-off of overstory woody plants at subcontinental scale and highlight the potential for such die-off to be more severe and extensive for future global-change-type drought under warmer conditions.
    Publisher: National Academy of Sciences of the United States
    Date Published: 2005-10-18
    Resource Type: Journal Articles
    Format: URL
    Language: English
    Continent: North America
    Rights: Copyright held by Publisher
    Source: Proceedings of the National Academy of Sciences, PNAS October 18, 2005 vol. 102 no. 42 15144-15148