Scientists Use Mathematical Modeling to Fight Encroaching Deserts
|Gobi Desert, Mongolia (15). |
Image Credit: Richard Mortel (CC BY 2.0).
But how do you fight the death of a landscape? In new research recently published in the American Physical Society’s journal Physical Review Letters, scientists from Ben-Gurion University of the Negev (BGU) in Israel have shown that we may be able to stop—or even reverse—the process by which drylands collapse into desert, using simple interventions at the desert border.
“One form of collapse is a domino-like process of plant mortality at transition zones between bare-soil and vegetation areas,” says Cristian Fernandez-Oto, a researcher at the University of the Andes in Chile. In this system, the edge of a desert encroaches on vegetated land like a destructive wavefront, pushing its way in and choking out the plants in its path.
While a postdoc at BGU, Fernandez-Oto worked with Prof. Ehud Meron and Omer Tzuk to simulate and study the behavior of such desert fronts as they moved through vegetation areas. In particular, the team wanted to know if there was a way to interrupt or destabilize the progression of a desert front that would otherwise leave behind a desert state.
Like many systems in nature, dryland vegetation grows and changes in a way that can be mathematically modeled. The vegetation pattern depends on positive feedback loops between plant growth and water transport to the growth location, so the team's BGU team's model incorporates these feedback features. The team started with an existing model for dryland vegetation, simplifying it a bit to match the system they wanted to study. A desert state in their model corresponds to a bare soil area devoid of vegetation.
|A view of Sede-Boqer campus of Ben-Gurion University at Midreshet Ben-Gurion in the northern Negev (a desert in southern Israel), where the research team was based. |
Image Credit: Public Domain
In fact, the researchers identified an instability—a turning point—in their analysis that led to ripples in the vegetation patterns in space and time and caused “fingers” of vegetation to grow backwards from the front, into the desert area. This suggests that small structural changes in boundary zones can actually reverse a desertification front. Furthermore, explains Fernandez-Oto, “Once a desertification front has been shifted to a recovery front, a gradual self-recovery process begins with no need for further intervention.”
The researchers suggest possible ways to bring this mathematical instability to life— by introducing a new plant species that changes the water-uptake rate in a boundary zone, for example, or by guided clearcutting to reduce the competition for water. The intervention depends on the situation.
Of course, seeing the results of a mathematical model isn’t the same as seeing real plants sprout up in a once-lifeless area, but this research suggests we can get there and provides some insight on how. More than 40% of the Earth surface land is covered by drylands, and this percentage is likely to increase with climate change, says Fernandez-Oto. Through their work, the research team hopes to help transform fragile ecosystems into places of resilience.
I know that this seems a little beyond our time but if we could in the future make it happen. It is not far fetched. If we took ice from the asteroid belt in our solar system and dropped it on the desert we could cool our world rapidly. Thanks for reading my comment.
Thursday, February 14, 2019 at 8:06 AM