How to save the “skin” of the desert?

BETWEEN LOSSES AND PROFITS

Biological crusts may have evolved to withstand drought, but not humans.

The wall built on the border between the United States and Mexico runs along the southern border of the Organ Pipe Cactus National Monument. Border patrol vehicles kick up an almost permanent cloud of dust as they travel back and forth through what was once the primary habitat of biological crust. When Antoninka arrived in the area to assess the impact of the traffic and construction machinery on the crusts, Antoninka made a predictable discovery: the crusts are not doing well. Every step he takes raises a small cloud of volatile dust because no biological crust holds the earth in place in the summer monsoon.

This disappearance affects Antoninka personally, she who studies biological crusts as she would find old friends. “Here is a Heppia ! And one Collema ! she exclaims. While defining the area for collecting scab for her team that day, she happily discovers a surprise formation. Crouching, she takes a closer look at the dark spot on the beige sand. “Ooooh, how beautiful you are! Hello in there!”

Confused by the mass disappearance of biological crusts in the southwestern United States under the influence of construction, fires and other human activities, Antoninka and Bowker now grow their own crust in the laboratory. Their ambition is to create candidates for transplantation to contribute to the restoration of biological crusts.

It was this project that brought Antoninka and her team to the Sonoran Desert to collect fragments of healthy biological crust from the Organ Pipe National Preserve, as well as the Tonto and Casa Grande National Monuments. The healthy crust that the researchers have taken from these three sites will be used as seeds for cultivation in the laboratory.

Fortunately for scientists, they only need small pieces, because organisms in the biological crust are totipotent: each individual cell can reproduce the whole organism under the right conditions.

And by appropriate is meant difficult. With their constant temperature, shade and humidity, greenhouses provide a life far too peaceful for biological crusts. In this environment, experiments fail. Outdoor grounds sheltered from extreme heat and dryness are the ideal recipe for curing these small plants without killing them. The team is currently growing new crusts on jute and other biodegradable substrates, making it easier to transport them and establish them in a new environment.

“Antoninka is at the forefront of the movement. That’s what drives discipline so fast, ”said Akasha Faist, an ecologist and grassland researcher at New Mexico State University. For years, ecologists had been waiting for the biological crust to reform itself, but efforts by Antoninka and other scientists have begun to accelerate this natural process.

So far, researchers have grown the biological crust based on the conditions of its original location. However, Reed’s work at the United States Geological Survey has shown that even the slightest variation in temperature and precipitation can put deadly stress on those organisms that are already on the verge. Instead of growing the crusts under current conditions, Antoninka wants to place them in warmer and drier places to anticipate global warming.

“You have to stop taking into account the current situation and look ahead,” Antoninka said. “I do not know if it will work, but we have to try. »

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