In the southwestern United States, non-native grass invasions have increased wildfire occurrence in deserts and the likelihood of fire spread to and from other biomes. Wildfires were historically small and infrequent in the warm deserts of western North America, with minimal impact on the desert vegetation. In recent decades, the fire regime has shifted with the spread of non-native grasses. Fires are increasingly burning large areas in desert habitats, largely driven by grassification, the physiognomic conversion of shrublands to grassland by non-native grass invasions. This conversion is especially concentrated at the upper elevational and northern latitudinal boundaries of the Sonoran Desert, which are transition zones to adjacent fire-prone biomes.
To better understand the changing nature of fire in the desert, presenters discuss their findings on the fire dynamics of the 2020 Bighorn Fire in the Santa Catalina Mountains on the outskirts of Tucson, Arizona. This presentation is based on research published in Frontiers.