| 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. |
| Genre: | Article |
| ProdID: | 70014541 |
| Citation Author: | Davis, O. K.; Turner, R. M. |
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| Citation End Page: | 193 |
| Citation Issue: | 3-4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Review of Palaeobotany and Palynology |
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| Citation Number Of Pages: | 17 |
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| Citation Search Results Text: | Palynological evidence for the historic expansion of juniper and desert shrubs in Arizona, U.S.A.; 1986; Article; Journal; Review of Palaeobotany and Palynology; Davis, O. K.; Turner, R. M. |
| Citation Start Page: | 177 |
| Citation Volume: | 49 |
| Citation Year: | 1986 |
| Type: | citation/reference |
| Text: | Palynological evidence for the historic expansion of juniper and desert shrubs in Arizona, U.S.A.; 1986; Article; Journal; Review of Palaeobotany and Palynology; Davis, O. K.; Turner, R. M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/0034-6667(86)90026-6 |
| Date Other: | Wed, 1 Jan 1986 00:00 -0600 |
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