Community Structure and Demography in a Saline Pan-Dune Mosaic in the Western Mojave Desert

Rasoul Sharifi,Philip Rundel,William Brostoff

doi:10.5642/aliso.20173502.04

Abstract

A unique saline ecological system formed by an extensive mosaic of small clay pans and low stable dunes exists within Edwards Air Force Base in the western Mojave Desert of California. This ecosystem lies between the large Rosamond and Rogers dry lakes on the old Pleistocene lakebed of Lake Thompson. Plant communities on the low and relatively stable dunes were broadly classed as saltbush scrub, with a total canopy cover of 30–36%. Atriplex confertifolia was the typical dominant, with Ericameria nauseosa as an important associate. Taller dunes of younger age and less saline soils had similar plant cover, but a distinct plant community with Atriplex canescens and Krascheninnikovia lanata as dominants and Yucca brevifolia as a common associate. Flat areas adjacent to the dunes were dominated by a virtual monoculture of Atriplex confertifolia. Aboveground shrub and bunchgrass biomass including dead material varied from 503 to 1204 kg ha−1, low in comparison to similar plant communities in the Great Basin. The absence of small saplings and seedlings of many shrub species suggests successful establishment is highly episodic. Seedlings were abundant only in Isocoma acradenia.

Highlights

While most desert soils are only mildly alkaline, markedly saline habitats are widespread scattered and local in occurrence throughout the Great Basin and, less frequently, in the Mojave Desert and western Sonoran Desert
More typical of the Great Basin, unique but poorly described saline habitats can be seen in the Antelope Valley located in the western margin of the Mojave Desert in Los Angeles and Kern counties of southern California
The clay fraction was virtually absent from all the dune sites, while silt fractions varied from 5–21% in Dunes 1 and 2 to 21–26% in Dune 3

Summary

Introduction

While most desert soils are only mildly alkaline, markedly saline habitats are widespread scattered and local in occurrence throughout the Great Basin and, less frequently, in the Mojave Desert and western Sonoran Desert. More typical of the Great Basin, unique but poorly described saline habitats can be seen in the Antelope Valley located in the western margin of the Mojave Desert in Los Angeles and Kern counties of southern California. These unusual habitats have a significant conservation value because of the presence of a number of rare, threatened and/or endangered plant and animal species (EAFB 2008). These lie entirely within the boundaries of EAFB, with the larger Rogers Dry Lake having a long history of aviation use ranging from the development of special aircraft for the U.S Air Force to its service as a recovery site for early Space Shuttle landings

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Conclusion