Researchers examining effects of foreign plants, global warming

Thursday, Nov. 2, 2000 | 11:12 a.m.

Plants not native to the Nevada desert, combined with global warming, could present an increasing danger of wildfires, a team of Nevada scientists has discovered.

In findings published in the science journal Nature on Wednesday, the team detailed the first results of an ongoing study on 200 pristine acres of the Nevada Test Site.

They applied high levels of carbon dioxide on untouched desert plots to duplicate the conditions of global warming. Three plots were exposed to levels expected in 2070, at the current rate of warming.

Red broom and Mojave cheat grass -- plants not native to the Nevada desert that have taken root here -- flourished under the increased exposure to the gas, they reported.

The grasses exposed to more carbon dioxide produce up to 300 percent more seeds that grow during wetter years.

Over the three years of the experiment, the carbon dioxide gas seems to have had no effect on native desert plants, the scientists said.

The finding is significant, because while wildfires in the desert tend to come in cycles about every 75 years, greater grass growth encourages fires every three to four years, the Nature article said.

The authors include UNLV biologist Stanley D. Smith, University of Nevada, Reno, biochemists Stephen Zitzer and Jeffrey Seeman, Desert Research Institite Vice President for Research and Business Development James Coleman and DRI remote sensing scientist Lynn Fenstermaker.

The experiment could continue over the next 20 years, giving scientists a look at the future effects of increased carbon dioxide on the desert, which covers 35 percent of the Earth, Smith said.

The nine plots in the desert are located at the Nevada Desert FACE Facility, in the Mojave Desert northwest of Las Vegas.

It is the only arid ecosystem research site in the world looking at carbon dioxide's effects in a natural setting, Coleman said. As part of a larger environmental research experiment, it is one of only five in the world.

The facility uses the Free Air Carbon Dioxide Enrichment system to create an atmosphere expected in the future. The U.S. Department of Energy allowed the scientists to use land never disturbed by cattle grazing or human intrusion, Smith said.

The work was significant for the university system as well, because of the stature of the journal Nature.

"We're very excited to see the work of our scientists recognized in such a prestigious publication," Jane Nichols, chancellor of the University and Community College System of Nevada, said.

"So many of our faculty are engaged in world-class research and as their reputations grow, so does the reputation of our institutions," Nichols said.