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Environment: Healing the desert

Research project explores cryptobiotic soil restoration

Cryptobiotic soil in southeastern Utah. Photo courtesy USGS.

By Summit Voice

FRISCO — Led by University of Colorado researchers, scientists from around the country are teaming up to see if they can help restore damaged desert soils by growing biological soil crusts in a lab, then transplanting them to areas that have been damaged by military exercises and other activities.

The research could provide some clues as to how make desert ecosystems more resilient to climate change, and also has public health implications, since since the disturbance of biocrusts can trigger the release of significant amounts of atmospheric dust, a dominant pollutant in some desert metropolitan areas.

Fragile cryptobiotic soil plays a crucial role crucial in some desert ecosystems by preserving moisture, reducing erosion and fixing nitrogen. The crusts are extremely fragile  — even just a footprint can disturb the organisms, and it can decades for the damage to heal.

Biocrusts can cover up to 70 percent of the ground in some arid ecosystems and are dominated by cyanobacteria, lichens, mosses, fungi and bacteria, said CU-Boulder assistant professor Nichole Barger.

“Biocrusts often are associated with increased soil nutrients and water retention, but their most important task is to stabilize soil surfaces against wind and water erosion,” Barger said. “While most biocrusts are relatively resilient to wind and water erosion, they are highly susceptible to compressional forces like those generated by foot and vehicle traffic associated with ground-based military activities,” she added.

The project is aimed at restoring fragile habitats in desert areas that have been affected by the movement of U.S. military vehicles, including tanks, as well as high foot traffic. The team has two U.S. Department of Defense study sites — Fort Bliss, which straddles southern Texas and New Mexico and is located in a hot desert environment, and the Dugway Proving Ground in northwest Utah, in a cool desert environment.

“You can go to these places and see that the biocrusts in the old tank tracks, for example, are completely different than nearby biocrusts undisturbed by military activity,” Barger said.

The first step of the program will be to grow biocrusts in laboratories at Arizona State University.

“Our approach will be to expose laboratory biocrusts over time to a physiological ‘boot camp’ that includes increasing stressors like heat, light and dryness,” she said. “By doing that, we believe the biocrusts we eventually transplant into the study areas will have a higher probability of survival.”

The lab-grown biocrust products will be dried, bagged and transported to field test sites at each respective military installation and sprinkled on soil surfaces, said Barger.

Once in the field, the stress-adapted biocrusts developed in the lab nurseries for both hot desert and cool desert environments will be combined with other soil stabilization strategies, she said. The team, for example, will also experiment with adding polyacrylamide — a soil-stabilizing compound shown to increase soil porosity and reduce erosion, compaction, dustiness and water run-off — to the mix.

The researchers will evaluate the effectiveness of such soil “inoculations” and determine the optimum dosage for the test sites. Following the assisted recovery of the local biocrusts at Fort Bliss and the Dugway Proving Ground, the team will begin a series of seeding trials to develop strategies for native plant re-establishment, Barger said.

The last step of the project will involve a series of rainfall simulations and wind tunnel experiments combined with broad-scale soil erosion modeling to evaluate the influence of biocrust and native plant restoration in terms of precipitation and soil erosion.

While DOD military installations cover nearly 30 million acres — 70 percent of which are located in arid regions of the West — Barger said the research also could aid in the effective management of other federal lands. “We think our work on biocrusts also will be of interest to land managers at agencies like the Bureau of Land Management and the U.S. Forest Service,” Barger said.

The project is being funded by a five-year, $2.3 million grant from the Strategic Environmental Research and Development Program, the U.S. Department of Defense environmental science and technology program that partners with the U.S. Department of Energy and the Environmental Protection Agency. The research team also includes Jayne Belnap, Michael Duniway and Sasha Reed from the U.S. Geological Survey’s Biological Resources Division in Moab, Utah and Ferran Garcia-Pichel of Arizona State University in Tempe.

The research project also has health implications, said Barger, since the disturbance of biocrusts can trigger the release of significant amounts of atmospheric dust, a dominant pollutant in some desert metropolitan areas.

“There is a broad societal interest in stabilizing dryland soils in order to protect not only the functioning of local ecosystems but also human populations that reside in surrounding communities,” she said. “In terms of tackling an important environmental issue, this is by far the most exciting research project that I have been involved in,” said Barger, who has worked in Hawaii, Central America, South America, China and South Africa.

 

 

 

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