Introduction to the special issue on the changing Mojave Desert

The Mojave Desert, which lies between the Great Basin Desert in the north and the Sonoran Desert in the south, covers an estimated 114 478–130 464 km² of the south-western United States and includes parts of the states of Nevada, Utah, Arizona, and California, with the amount of land mass dependent on the definition (Fig. 1; Rowlands et al., 1982; McNab and Avers, 1994; Bailey, 1995; Groves et al., 2000). This desert is sufficiently diverse to be subdivided into five regions: northern, south-western, central, south-central, and eastern (Rowlands et al., 1982). It is a land of extremes both in topography and climate. Elevations range from below sea level at Death Valley National Park to 3633 m on Mt. Charleston in the Spring Range of Nevada. Temperatures exhibit similar extreme ranges with mean minimum January temperatures of −2.4 °C in Beatty, Nevada and mean maximum July temperatures of 47 °C in Death Valley. Mean annual precipitation varies throughout the regions (42–350 mm), is highest on mountain tops, but overall is low (Rowlands et al., 1982; Rowlands, 1995a). The distribution of precipitation varies from west to east and north to south, with >85% of rain falling in winter in the northern, south-western and south-central regions. In contrast, the central and eastern regions receive a substantial amount of precipitation in both winter and summer. The variability in topographic and climatic features contributes to regional differences in vegetation.