A team of researchers has developed a multi-faceted process to study arid and semiarid landscapes that takes into account the wide range of factors influencing changes that can result in desertification.
Led by Debra Peters, research scientist for the U.S. Department of Agriculture's Agricultural Research Service at the Jornada Experimental Range in southern New Mexico, the team of USDA and New Mexico State University researchers published their findings in the June 2006 issue of BioScience. The article is titled "Disentangling Complex Landscapes: New Insights Into Arid and Semiarid System Dynamics."
Almost 40 percent of the Earth's surface and 20 percent of the world's population are found in regions that are under threat from desertification, which can result in the loss of grass and degradation of soil as grasslands are converted into woody-plant-dominated landscapes.
Although many research methods exist to study various facets of this process, more complete understanding of desertification can be achieved by looking back in time at historic legacies, considering environmental factors and studying soil, typography and soil parent material. Also considered is the influence of wind, water and animals as they transport water, nutrients, soil particles, plant litter and seeds. The redistribution of those resources also is weighed in the landscape reorganization.
"Previously we looked at small areas and used that information to make guesses about the large area, to extrapolate to the big area, and that doesn't work very well when things are really complex," Peters said. "And so then we shifted to say, really, the complexity is what's interesting and important."
The researchers offer a six-step operational scheme to unravel the complex influences of these variables. The first step is to "look up" to assess the broad scale, then "look back" in time to determine the role of past events on the present landscape. Third, "look around" to consider adjacent spaces and the influence of wind, water and animals as connecting transport vectors. "Look down" to determine fine-scale properties and processes of the landscape, then integrate the information from broad scale to fine scale to determine the most important influences. Finally, "look forward" in time to the effects of variable environmental factors from the current landscape to the future.
Members of the research team also are part of the Jornada Basin LTER (Long Term Ecological Research) project funded by the National Science Foundation. They will now move into experiments and computer modeling to confirm their findings, integrate the information and make future predictions.
The Jornada Experimental Range is located in the northern portion of the Chihuahuan Desert, the largest desert in North America.
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