Alien species such as red brome are spreading fire through native communities that often have few evolved defenses against such disturbances. Researchers are conducting detailed studies to better understand how increased fire size and frequency can affect desert ecosystems, and how native plants and animals can be protected. Their studies are thoroughly exploring the fire and weed cycle, looking at how fire changes nutrients in the soil, which changes the plants that are there, and in turn how animals respond to this dramatic change in habitat.

Native Mojave and Sonoran Desert plants are particularly vulnerable to fire. Although some species can resprout after burning if the fire intensity is not too high, few can tolerate successive burns. Invasive alien grasses generally increase in dominance after fire, creating conditions that promote repeated burning. Other research focuses on understanding the mechanisms of invasion.

Records from federal land management agencies show an increase in Mojave Desert fires over the past two decades. Expanding human use of desert lands may be behind some of the increase, but the pattern holds even in remote areas where fires are almost all lightning-caused. The increase in fires seems to be due to the alien annual grasses, which provide a lasting fuel source.

As in the Mojave, the fire problem in the Sonoran Desert is worsening. A 1994 wildfire in Saguaro National Park, Arizona, was spread by red brome. WERC researchers are studying the effects of this fire through time with a detailed census and monitoring effort both inside the burn area and on adjacent unburned lands.

  Nonnative Grass Invasions and Fire in the Mojave Desert
  Nonnative Grass Invasions and Fire in the Sonoran Desert