Buffelgrass is like the cockroach of the Sonoran desert. This invasive species, introduced from the African savannah, has gained a foothold in southern Arizona, crowding out native plants and threatening native wildlife populations. Dense buffelgrass stands compete with native plants for precious desert water, crowd out germinating seeds with their deep roots, and spread wildfires through an ecosystem ill-adapted to fire.
But since 2005, a group of dedicated volunteers have been working to eradicate buffelgrass from disturbed public lands. Volunteers from the Arizona Native Plant Society, the Arizona Sierra Club, Tucson Audubon Society, Sonoran Desert Weedwackers, and University of Arizona Soil, Water, and Environment Club have worked to dig up buffelgrass stands and prevent future invasions by planting native species. On December 3, 48 volunteers worked in an area of severely disturbed Bureau of Land Management (BLM) public lands at the base of the Waterman Mountains in the Ironwood Forest National Monument northwest of Tucson.
In the mid-2000s, this site had one of most severe infestations of buffelgrass in the entire Tucson Basin. Starting in 2005, the Arizona Sierra Club organized volunteers to manually remove buffelgrass on these BLM-managed lands. Since 2008, a core group of Arizona Native Plant Society volunteers has worked to regularly apply herbicide to emerging buffelgrass, plant native trees, and install water catchment areas to encourage desert restoration. Over 66 native plant species and thousands of planted native trees have taken hold across the site. Though invasive buffelgrass on this site is now under control, the soil remains charged with seed, so maintenance is constantly required.
Though hardly a new phenomenon—think Christopher Columbus and smallpox—globalization has opened the gates for the introduction of non-native species into ecosystems throughout the world. Invasive species are estimated to cost about $138 billion in environmental damage and losses each year, and are estimated to affect 1.7 million acres of U.S. wildlife habitat each year. Other examples of invasive non-native species wreaking havoc on ecosystems include yellow starthistle, which now dominates almost 10 million acres of once-productive grazing land in northern California, and, in the animal world, the carrier pigeon, which, having spread through cities across the country, is estimated to cost over $1 billion annually in property damage.
Although many non-native species aren’t invasive and don’t disrupt their new environments, problematic disruptions arise when non-native species, freed from the pressures of co-evolved natural predators, thrive at the cost of native plants and animals. After habitat destruction, invasive species are considered to be the greatest threat to ecosystem biodiversity.
To help with future buffelgrass projects in Arizona, contact volunteer coordinator John Scheuring at jfscheuring@hotmail.com.
