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What to Plant When the Fires Go Out:
Scientists Battle Russian Invaders, U.S. Policymakers
The biggest bad guy in the West, at least to people who study plant life on the prairies, is an invasive species that crowds out native grasses, dies early in the growing season, and becomes fuel for the fires that tear across the region.
Cheatgrass, a fast-growing weed that originated in Russia, is one of a number of invaders that have taken over the American West in the last 30 years, leaching nutrients from the soil and supplanting local species. Researchers at the AAAS Annual Meeting say they have in hand the genetic resources to do battle with the invaders, but state and federal government policies are not allowing them to put their knowledge to work.
"Controversies exist on what plants to use in re-vegetating burned and degraded rangeland and grassland sites in the United States," says Kenneth Vogel, a plant geneticist for the U.S. Department of Agriculture and adjunct professor at the University of Nebraska, Lincoln. "People assume that local collections of native ecotypes are the best adapted for re-vegetating, but we can clearly show that many cultivars of tall grasses are much better adapted for the great plains."
Much is at stake in the decision regarding what and where to plant, as plant life plays a crucial role in the severity and duration, and even the type, of conflagrations that consumed 6 million acres of western lands in 2002.
"Grassy lands are critical to making very frequent, relatively light fires possible and that make controlled burning feasible," Stephen Pyne, a fire historian and professor at the University of Arizona. "We've lost that. We've shifted lands into all kinds of woody material, living and dead. The target ought to be to get the grasses back in."
But to do this, native grasses need a hand up from science, says Richard Dunne, a seed producer and owner of the Wind River Seed Company, near Manderson, WY. He notes that most of the "local ecotypes" favored by recent government policies are poorly prepared to do battle with invasive species.
"Given the onslaught of fire and of weeds such as leafy spurge, toadflax, and cheatgrass, I believe the public must consider the use of improved cultivars of native plants, with improved survival traits such as greater seedling vigor, as necessary in combating aggressive invaders," Dunne says. "We could lose our forests and rangelands to weeds if we target our scarce resources incorrectly. To date, no substantial effort to improve the weed fighting ability of natives has been mounted, nor do I know of such a priority being considered."
Dunne and Vogel question the scientific assumptions underlying a recent federal contract for native seed production that was sponsored by the U.S. Bureau of Land Management, the Bureau of Indian Affairs, the Fish and Wildlife Service, the National Park Service, and the Forest Service invites seed producers to produce seed of locally collected plant material for re-vegetation use in collection region.
"This effort is going to cost the government a lot of money," Vogel says. "It all comes down to the best plant material to use, and a lot of people with a limited background in genetics are pushing for the use of local collections of native plants."
Vogel argues that the effects of migration, drift and selection have restricted genetic variation among local ecotypes or collections. He and Dunne say that the seed of cultivars can be produced more economically than the seed of local ecotypes.
To Pyne, the debate over what plants to use in re-vegetating western lands illustrates the "peculiar way that American society has evolved politics and practices to cope with fire's threats and utility."
"The United States does not have a fire problem," Pyne says, "It has many fire problems. The core concern, however, resides in the West, where extensive public lands overlay a naturally fire-prone geography. In such circumstances, four options exist: Do nothing. Suppress. Do the burning yourself. Change the combustibility of the landscape. None is sufficient by itself; the requirement is to mix and match, adjusted to specific sites. The outcome should be to create a landscape in which we can control the fires we don't want and promote those we do."
14 February 2003