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Palynological evidence for the historic expansion of juniper and desert shrubs in Arizona, U.S.A.

Review of Palaeobotany and Palynology

By:
and
DOI: 10.1016/0034-6667(86)90026-6

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Abstract

Analysis of the sediment of Pecks Lake, Yavapai County, Arizona, has permitted the first reported palynological evidence for the historic expansion of juniper and desert shrubs in the American Southwest. The palynological evidence is supported by the comparison of modern and historical photographs, which shows the regional expansion of pinyon-juniper woodland, and the local increase of mesquite and creosote bush. A gradual increase in juniper pollen percentages began over 2000 years ago, but the rate of increase abruptly accelerated after the historic introduction of grazing animals. In contrast, juniper percentages did not increase during a prehistoric interval of intense disturbance by humans, about A.D. 1200, and a different weed flora was present. Prehistorically, water depth was greatest at ca. 600 B.C. and was lowest just prior to the arrival of Europeans. Regional climate has gradually cooled since the beginning of the record at 2630 B.P. ?? 1986.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Palynological evidence for the historic expansion of juniper and desert shrubs in Arizona, U.S.A.
Series title:
Review of Palaeobotany and Palynology
DOI:
10.1016/0034-6667(86)90026-6
Volume
49
Issue:
3-4
Year Published:
1986
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Review of Palaeobotany and Palynology
First page:
177
Last page:
193