Native to the Old World, and introduced to the Sonoran Desert for livestock grazing, buffelgrass' thirst for water and nutrients is unparalleled in this environment, and it seems to follow humans wherever they go. Bunches of the grass are now common sights along highways in Southern Arizona.
And there's a risk that climate change may only make these problems worse, according to Travis Huxman, a University of Arizona assistant professor in the Department of Ecology and Evolutionary Biology. A recent report from the Intergovernmental Panel on Climate Change indicated that rain patterns might shift in the Southwest, Huxman said, giving hardy, non-native species like buffelgrass even more of a competitive advantage.
Last year, the Weekly did a story on the proliferation of Pennisetum ciliare in the Southwest and efforts to eradicate it ("Bad Grass," March 30, 2006). We decided to check in with a biologist, Sue Rutman, at Organ Pipe Cactus National Monument to see how those efforts are going. The 330,000-acre monument, which abuts Mexico, experienced a buffelgrass explosion in the mid-'80s.
A year ago, Rutman painted a "worst-case scenario" in which the spread of buffelgrass could spell doom for "the big columnar cactus," except in protected places. Those concerns persist today, even though the monument hasn't been as inundated as other places.
"We're not nearly as bad as, say, 'A' Mountain," she said. "I mean, we have fairly low-density stands compared to that, and that's the way we want to keep it."
To that end, two volunteers--robust retirees--work their way through the monument every winter season, hand-pulling the stands. She said they have been "very successful."
"I have photographs and data and memories of what it used to be like, and it's not like that anymore," she said. "You can drive through Organ Pipe and not see a buffelgrass on the main highway and on any of the roads, and you can't say that about any other stretch of the highway in Southern Arizona. That's something to be proud of."
But even with two pairs of hands picking the Organ Pipe landscape clean of buffelgrass, Rutman declined to say she was optimistic about the future.
"This thing could eat our lunch and get out of control very quickly," she said. "It's such a huge area to survey and control that it's scary. We're seeing it more frequently in very remote areas, away from the border."
Rutman said that in the past, buffelgrass stands in the monument were concentrated within a half-mile of the border with Mexico, indicating that it was coming up from the south. Now, it's showing up in the middle of the monument.
"I'm not sure what to think of that," she said. "Maybe they were always there, and we never found them or knew of them, or maybe they truly are new, and this population is exploding and jumping around a lot. We can't really tell for sure. There's never been and probably never will be a full, 100 percent survey of Organ Pipe for buffelgrass."
Illegal immigration is also having an impact on eradication efforts, according to Rutman. For one thing, people along the border are so concerned with immigration that taking care of buffelgrass, rightly or wrongly, becomes a far less prominent priority.
"I don't know what kind of long-term repercussions that's going to have," Rutman said.
Organ Pipe staff members have been concerned about the safety of volunteers; park ranger Kris Eggle was killed in 2002 while reportedly trying to help Border Patrol agents apprehend two men suspected of committing murder.
"That has affected where (buffelgrass volunteers) can go," Rutman said. There haven't been any major run-ins yet, she added, but they prefer to err on the side of caution, and that means they weren't allowed to go everywhere they wanted this past winter.
Rutman also raised the possibility of something far more insidious: Wherever illegal immigrants go, buffelgrass could possibly be following.
"A colleague of mine was up in a helicopter, flying over the south boundary--and scared a whole bunch of migrants, and they went running back into Mexico along the trail that they had come in on," she said. "You could look at this photograph and see that they had run into and out of a stand of buffelgrass, and I'm thinking, 'Oh, how many seeds got stuck on their pants or their shoes or whatever, and (got) walked into Organ Pipe?'
"Even though we don't have any real data to say that migrants and smugglers are bringing things in, it seems likely that they do. So there are all sorts of ways this current border situation could affect how well buffelgrass does."