Fire stories from the national parks highlight events, incidents, and the like, associated with fire and fuels management, as well as fire education, technology, partnerships, and more. Stories highlight work related to Department of the Interior initiatives as well as local and regional initiatives.
Herbicides Effective on Invasive Grass Changing the Fire Regime of the Sonoran Desert
Saguaro National Park, Arizona
Cohesive Strategy—Maintain and Restore Resilient Landscapes*
Saguaro National Park is battling a non-native, invasive grass that is threatening to convert fire-proof Sonoran Desert vegetation into highly flammable grassland. Buffelgrass (Pennisetum ciliare) creates heavy continuous fuel loads. In the park, fuel loads have been measured from one to four tons per acre, which is many times greater than natural desert fuel loads. Historically, fires were extremely rare in the desert, but buffelgrass has the potential to create a grass-scrubland prone to intense fires.
Buffelgrass currently infests about 2,000 acres of the park and is spreading exponentially. A warmer climate will exacerbate the situation. Many scientists believe that local extinctions of saguaros could occur, and the desert and the wildlife it supports could be changed forever if buffelgrass goes unchecked.
The park has been fighting buffelgrass since the early 1990’s. Control efforts include manually pulling plants, mainly by volunteers and civic groups, and herbicide application with backpack sprayers used by park staff and contracted conservation corps. Approximately one-third of the annual fire funding budget for control of invasives in the park goes to buffelgrass treatments and similar non-native grasses.
As of 2013, buffelgrass has been largely removed from over 500 acres within the park. Where it has been removed, native plant communities have responded well, and native plants are reoccupying areas where many had been suppressed or outcompeted by buffelgrass. Treated areas include Wildland Urban Interface areas along the park boundary, where wildfires that would be fueled by buffelgrass can threaten the homes and lives of our neighbors as well as critical infrastructure.
Despite the successes, buffelgrass is expanding faster than control efforts can keep pace. Different strategies are being considered, including spraying with a helicopter. The park has conducted or funded research into factors that affect buffelgrass growth, treatment methods for controlling it, ways to minimize the impact of treatments on native plants and animals, changes in ecosystem properties following invasion, and restoration of areas after buffelgrass is removed.
The fight against buffelgrass is a major collaborative effort between many governmental entities and private citizens. Dozens of groups and individuals came together in 2008 to form the Southern Arizona Buffelgrass Coordination Center, whose mission is to provide a regional information center that emphasizes an integrated management approach to control buffelgrass in Southern Arizona (www.buffelgrass.org).
More information is on the park’s website at http://www.nps.gov/sagu/naturescience/invasive-plants.htm. The Southwest Fire Consortium has produced a video about the issue: http://www.youtube.com/watch?v=zBi354Q4RuE.
Contact: Perry Grissom, Fire Ecologist
Phone: (520) 733- 5134