A long-term vegetation history of the Mojave-Colorado Desert ecotone at Joshua Tree National Park

Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate A.

Abstract:

Thirty-eight dated packrat middens were collected from upper desert (930-1357?m) elevations within Joshua Tree National Park near the ecotone between the Mojave Desert and Colorado Desert, providing a 30?ka record of vegetation change with remarkably even coverage for the last 15?ka. This record indicates that vegetation was relatively stable, which may reflect the lack of invasion by extralocal species during the late glacial and the early establishment and persistence of many desert scrub elements. Many of the species found in the modern vegetation assemblages were present by the early Holocene, as indicated by increasing S?renson\‘s Similarity Index values. C₄ grasses and summer-flowering annuals arrived later at Joshua Tree National Park in the early Holocene, suggesting a delayed onset of warm-season monsoonal precipitation compared to other Sonoran Desert and Chihuahuan Desert localities to the east, where summer rains and C₄ grasses persisted through the last glacial?interglacial cycle. This would suggest that contemporary flow of monsoonal moisture into eastern California is secondary to the core processes of the North American Monsoon, which remained intact throughout the late Quaternary. In the Holocene, northward displacement of the jet stream, in both summer and winter, allowed migration of the subtropical ridge as far north as southern Idaho and the advection of monsoonal moisture both westward into eastern California and northward into the southern Great Basin and Colorado Plateau. Copyright 2009 John Wiley & Sons, Ltd.

Genre:

Article

ProdID:

70003999

Citation Author:

Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate A.

Citation Contributing Office:

Branch of Regional Research WR

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

236

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Journal of Quaternary Science

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

15 p.

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

A long-term vegetation history of the Mojave-Colorado Desert ecotone at Joshua Tree National Park; 2010; Article; Journal; Journal of Quaternary Science; Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate A.