Israeli scientists at Ben-Gurion University of the Negev have developed a model that shows that ecosystems can be rescued from desertification by means of simple interventions at the desert border in the form of “vegetation fingers.”
Desertification is a process of ecological degradation in arid climates as a result of human activity, climate change and various additional factors.
Agricultural yields decrease as the result of land degradation, a process that can lead to hunger, strife and massive emigration.
“Deserts have been expanding for decades, but it doesn’t have to be an irreversible process,” says Prof. Ehud Meron of the Swiss Institute for Dryland Environmental and Energy Research (SIDEER), one of the Jacob Blaustein Institutes for Desert Research at BGU’s Sde Boker campus.
According to the United Nations Convention to Combat Desertification (UNCCD), over 30 percent of the land in the US is affected by desertification. Similarly, one-fifth of Spain’s land mass is at risk of turning into desert, while in China sand drifts and expanding deserts have claimed nearly 700,000 hectares of cultivated land, 2.35 million hectares of rangeland, 6.4 million hectares of forests, woodlands and shrublands since the 1950s, according to the international body.
Meron’s research group has developed a platform of mathematical models for dry ecosystems that serve as an incubator for novel ideas on how to combat and even reverse the process of desertification.
In a recent study that appeared in Physical Review Letters, postdoctoral fellow Dr. Cristian Fernandez-Oto, Israeli Ph.D. student Omer Tzuk and Prof. Meron, used this platform to explore the possible role of instabilities in reversing desertification.
One form of desertification is a domino-like process of plant mortality at borderlines between bare-soil and vegetation areas that results in a desertification front and the gradual replacement of vegetation with bare soil.
“We uncovered an instability by which straight desertification fronts develop vegetation fingers that grow backward into bare soil areas and thereby reverse the desertification process,” said Meron.
“The instability is realized under conditions of fast water transport towards the growing vegetation finger. Such water transport not only accelerates the finger’s growth but also inhibits vegetation growth on both sides of the finger, and thereby drives the instability,” he explained.
Once the instability sets in, a gradual self-recovery process begins with no need for further intervention.
“Other types of front instabilities can be envisaged that result in self-recovery, but additional studies, both theoretical and empirical, are needed to fully explore these ideas and their translations into land-management practices,” Meron added.
With desert covering a large part of its surface, Israel has developed solutions to make the desert bloom, and many countries contending with desertification have imported the ideas and the technology.
The country works closely with the UNCCD and its Executive Secretary to achieve the agency’s goals, plans and framework.