RESEARCHER REPORTS THAT INVASIVE GRASS DESTROYS SOIL NITROGEN, DEPLETES NATIVE DESERT PLANTS
SPOKANE, Wash. - University of Arkansas biology professor Raymond D. Evans and his colleagues have found that when cheatgrass invades an area, the amount of nitrogen available to plants in the soil decreases dramatically, possibly choking the life out of native desert plants.
Evans will present his findings today (Aug. 10) at a symposium, "Invasive Species in the Soil: Effects on Organisms and Ecosystem Processes," at the 84th annual meeting of the Ecological Society of America in Spokane, Wash.
The innocuous looking grass was brought from Eurasia to Washington State in the 1890s, and it quickly spread through the arid areas.
"In 30 years it basically took over the West," Evans said. The grass can now be found from Washington through Nevada, Utah, Idaho and parts of many other states.
In Canyonlands National Park, where Evans and Jayne Belnap of the National Park Service have conducted soil nitrogen studies, undisturbed areas sport small clumps of native grasses with areas of black biological soil crust in between.
But when cheatgrass invades an area, it grows in thick blankets, shutting out sunlight that microbiotic crusts need to fix nitrogen in the soil, Evans said. Cheatgrass dies back every year, but it adds little nitrogen back to the soil.
"It uses up all the nitrogen that other plans would normally take up," Evans said.
Large tracts of cheatgrass also use up nitrogen another way. The fields are susceptible to range fires that can spread for miles. The nitrogen tied up in plant litter literally goes up in smoke, Evans said.
The native plants have no tolerance to fire, because they have had little exposure to it in the past, Evans said.
The combination of fires, and low nitrogen content soil may drive out the native plants. But the cheatgrass seems to thrive under these conditions.
"That’s what people are finding with invasions. They can’t be reversed," Evans said.
The next step in Evans research will be to look at the plant’s responses to the nitrogen loss, he said.
# # #
Topics
Contacts
Raymond D. Evans, associate professor, biological sciences
Aug. 6-12: Doubletree Hotel (509) 455-9600
(479) 575-7093, devans@comp.uark.edu
Melissa Blouin, science and research communications manager
(479) 575-5555, blouin@comp.uark.edu
Headlines
Peter Ungar Chosen as Member of the National Academy of Sciences
A distinguished professor of anthropology and director of environmental dynamics, Ungar is the first U of A faculty member to be elected to the prestigious Academy.
Ag Technology Students Visit Greenway Equipment, Learn About Advances in Machinery
Members of the U of A's Agricultural Systems and Technology Club recently spent a day at the Greenway Technology Farm in Newport to learn about advances featured in John Deere tractors and machinery.
College of Education and Health Professions WE CARE Everywhere Campaign Kicks Off This Summer
Retractable scroll banners with the phrase "WE CARE Everywhere" are small enough to fit any suitcase and just waiting for your chance to shine in social media posts throughout the summer.
Staff Senators for 2024-25 Elected
Twelve newly elected staff members will begin serving the U of A staff community for three-year terms beginning July 1 on the university's Staff Senate.
Matlock Briefs Congressional Staff Regarding Crop Sustainability Research
Professor Marty Matlock briefed U.S. House of Representative and Senate staff members on research conducted by the U of A regarding the effects of management practices on crop sustainability.