FIRE ON THE MOUNTAIN.

Byline: Scott Maben The Register-Guard

PLEASANT HILL - Will regular fires on Mount Pisgah help save native plants from being overrun by non-native invaders?

It's a burning question that a pair of University of Oregon professors want to answer with a labor- intensive study on the mountain's south face.

The findings could support a proposal by Friends of Buford Park to reintroduce fire as a key tool in restoring habitat at Lane County's 2,363-acre Howard Buford Recreation Area, between Springfield and Pleasant Hill.

"You could be burning hundreds or even thousands of acres if you knew it was the right thing to do," said Bart Johnson, an associate professor of landscape architecture.

Managers face a race with time to save native species. False broom, for example, is a non-native grass that is rapidly spreading in some areas of the park. It grows well in either full sun or full shade and crowds out all other plant life.

Botanists and ecologists believe Mount Pisgah contains some of the best remnants of upland prairie and oak savanna habitat anywhere in the Willamette Valley. But it's nowhere near a pristine landscape.

Livestock grazing, fire suppression and other types of human interference have given scores of exotic plants a toehold. If left alone, the most invasive of the non-native species will virtually eliminate the grasses and flowers that thrived there prior to Western settlement, scientists believe.

And the loss of native plants is believed to be a big factor in the erosion of wildlife diversity, from insects to rodents to birds.

"In general, we believe native species provide the best habitat for native wildlife," Johnson said.

But land managers aren't sure how best to reverse the incursion, mainly because so little research has been done on these habitats. Johnson and Bitty Roy, an associate professor of biology, have set out to test a common assumption that fire benefits native species.

With the help of several volunteers, the two spent much of Thursday through Sunday on their hands and knees examining clusters of grasses and flowers growing in a 32-acre study area.

The state Department of Forestry burned about half of the area last October, creating a checkerboard pattern with four unburned sections that serve as the control for the experiment.

Johnson identified and cataloged the plants in each of 108 one-square-meter study plots to see how many of the 146 native and exotic plant species were growing there. In just one of those small squares, he and assistant John Koenig, a botanist, found 30 species. Sixteen of them were natives, and they estimated the native plants accounted for 50 percent to 75 percent of the total ground cover in the plot.

It's a good sign, Johnson said, but it's too early to draw any conclusions.

The data will be compared with observations taken in the same locations the previous two years, before the burn. Preliminary results could be available next month, Johnson said.

"By reinstating fires, we hope to stop the encroachment of conifers and small woody shrubs, and create benefits for the native plants over the exotics that have come in," he said.

Before settlers started putting them out, fires traditionally would burn off thatch, brush and tree seedlings, keeping upland prairies open and controlling the spread of Douglas fir on the edge of savannas, Johnson said.

Most of the native grasses and flowers, however, were adapted to fire and would easily survive. Some even thrive as a result of it.

"Camas blooms profusely after fire," Johnson said.

Some of the exotic species, however, also might benefit from fire.

Research on wet prairie habitat, found in lower elevations, suggests that native species respond better to flames. But it's possible that fire on Mount Pisgah could stimulate the proliferation of some invasive plants, making the problem worse, Johnson said.

"There is some evidence that exotics love fire," he said. "Fire opens up resources for plants to grow, so it's a question of who gets it first."

The experiment also gives Roy a chance to do one of the first studies on the role of pathogens in the invasive nature of certain exotic plants.

She's examining the insect predation and diseases that afflict four closely related pairs of native and invasive species. A widely held hypothesis suggests that some non-native plants are powerful invaders because they left behind their pests, their natural enemies, when they were transplanted.

"Up until extremely recently, nobody had ever tested it," she said. "And it's only been partially tested with insects."

Pathogens account for at least 50 percent of all biodiversity, Roy said, and play a crucial role in preserving the variety of species found in any area. In the absence of diseases or grazing animals to keep a plant's numbers in check, it spreads more rapidly and crowds out other species, she explained.

"If humans had no disease, we'd be more populous than we are now," she said.

Roy also hopes to answer a second question: Does fire reduce the pathogen activity of these plants? Fire does destroy the spore sources of plant diseases, she said, but the wind quickly redistributes them.

"I'm finding huge numbers of pathogens this year," she said. "I don't think fire makes that much of a difference."

Last fall's burn only covered upland prairie habitat. The research team hopes to do another controlled burn just uphill in an oak savanna this fall.

The work is supported by Lane County Parks, which manages the recreation area.

"We feel it's a real benefit to the park in terms of re-establishment of native species and forbs," county parks manager Rich Fay said.

The county also is interested in learning if areas dominated by native plants provide less fuel for fires than places where invasive, exotic species are abundant. Officials closed the park a couple of times in recent years because of high fire danger.

"So we think it's a real positive thing," Fay said.

The researchers hope to turn their work into a long-term study and plan to use early results in bids for grant money.

CAPTION(S):

Bart Johnson records data as John Koenig counts plant species in a plot near Mount Pisgah, where researchers set fires last fall to study its effects. Matt Visser and this is light text and this is more light text Pisgah: Some plants survive and thrive after fires Continued from Page A1 Brian Davies / The Register-Guard Matt Visser (right) and Bitty Roy take a close look at what's bugging native plant species at Mount Pisgah. E n v i r o n m e n t Scientists study whether flames hold the key to the future of native flora