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

Journal of Quaternary Science
By: , and 



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 Sørenson'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.

Publication type Article
Publication Subtype Journal Article
Title A long-term vegetation history of the Mojave-Colorado Desert ecotone at Joshua Tree National Park
Series title Journal of Quaternary Science
DOI 10.1002/jqs.1313
Volume 25
Issue 2
Year Published 2010
Language English
Publisher Wiley
Contributing office(s) Branch of Regional Research-Western Region
Description 15 p.
First page 222
Last page 236
Country United States
State Colorado
Google Analytic Metrics Metrics page
Additional publication details