USGS/Todd Esque

Saguaro cacti in buffelgrass, Javelina Picnic Area, Saguaro National Park, Arizona.

Historically, patchy fuels and sparse vegetation have limited individual fires to small areas in the hot deserts of North America, including the Sonoran Desert (Humphrey 1974; Schmid and Rogers 1988). Most Sonoran Desert vegetation is not adapted to fire and some important endemic plant species are vulnerable to recurring fire (Thomas and Goodson 1992; Wilson et al. 1994; McAuliffe 1995). Two species found in the Sonoran Desert, the saguaro cactus (Carnegiea gigantea) and foothill palo verde tree (Cercidium microphyllum), are very susceptible to wildfire (McLaughlin and Bowers 1982; Rogers 1985; Esque et al. 2004). Exotic grass invasions in desert regions can change the fire regime by providing fuel for fire where fire was once rare. In this article we describe how an invasive exotic plant—buffelgrass (Pennisetum ciliare)—is a management problem in the borderlands between the United States and Mexico. We also report the results of our study of buffelgrass fuel loads on two sites in Saguaro National Park, Arizona, and discuss management implications of buffelgrass-related fire risks.

Exotic grass invasions in desert regions can cause a change in the fire regime by providing fuel for fire where fire was once rare.