Have you been wondering why there has been an increased number of wildfires throughout Arizona over the past few years? Southwest Fire Science Consortium (SWFSC) has recently released a report on this recent uptick, and identifies invasive grasses as one of the leading culprits for these fires. 

Why are these plants so bad? When invasive plant species are introduced, they can overtake entire landscapes, crowding out native plants and creating a monoculture. The Sonoran Desert typically presents as a desert scrub or desert shrubland biome. The plants in these spaces can be widely spaced or patchy in their distribution with open areas in between. These open areas make it difficult for fire to spread, making the desert somewhat fireproof. As invasive plant populations grow the open spaces between plants fill in making it easier for fire to spread, shifting the naturally fireproof desert scrub to a grassland, and our naturally fireproof desert becomes more fire prone. 

These invasives contribute to what is called the grass-fire cycle. Invasive grasses can spread and establish themselves quickly; they burn very hot, carry wildfires further than they may naturally go, and recover quickly after a fire. Native Sonoran Desert plants, on the other hand, can take several years to recover after a wildfire. Over time, invasive populations result in greater likelihood for wildfires to start and increase the size of future fires, limiting the ability for native plants to reestablish themselves. As the grass/fire cycle continues, our ability to control the invasive plant populations decreases, and wildfires start to occur more frequently, outside of the typical fire season (May-June). 

Read SWFSC’s full report below to learn more about these invasive grasses, what the future of our desert looks like, and what we can do.