Reed stands by a plot hit with both heat lamps and light, regular water treatments. The ground looks trampled. It’s surprising that just a little water could cause this kind of damage. Reed and Belnap think the water gives the crusts just enough moisture to rev up metabolism, but not enough to replace the energy they’ve used, especially as heat speeds up evaporation.
What’s troubling is how quickly the warmed and watered crusts disappeared — they were barren in less than a year. “You can tell right away which ones got watered,” says Belnap. “Everything used to look like that over there,” she says, pointing to a distant control plot with visible, thick crusts.
“It was stunning and disappointing and somewhat gut-wrenching,” says USGS researcher Scott Ferrenberg, the lead author on a paper analyzing data from these experiments.
Other researchers, like Fernando Maestre, a professor at Rey Juan Carlos University in Spain, are doing similar experiments in other parts of the world. Nearly 75 percent of Spain is classified as drylands. “Climate models predict really, really high warming for Spain, particularly during the summer. And summer in Spain is already really hot,” he says. “We need to know what is going to happen before we can think of ways of mitigating it.”
Maestre’s experiments are showing results similar to those from USGS.
The future doesn’t look good for biocrust communities, and thus for the stability of desert soils, as we continue to careen toward a warmer climate. But researchers still hold out hope. “We’re trying to turn to a more optimistic phase to see if there’s some way we could help these communities to return,” says Ferrenberg. Several universities are trying to culture biocrust organisms in greenhouses and reintroduce them to damaged landscapes. Results are mixed so far. In China, government scientists sprayed a cyanobacteria-loaded slurry over growing sand dunes and stopped their advance. But recent experiments in New Mexico and Utah have been hit-or-miss, and it’s not clear why. “The jury’s out in terms of restoration and how much success we might have in the face of climate change,” says Ferrenberg.
Scientists are also exploring assisted migration, a controversial topic in ecology where species are moved from a place they currently thrive in to places they might survive as the globe warms. The Moab USGS team just began a new “common garden” experiment to see which crust communities might fare the best in a warmer Utah. They gathered crust samples from different ecosystems across the Southwest and grew them in a greenhouse at Northern Arizona University. Early this year, the team spread those samples in adjacent Utah plots. Similar to climate manipulation plots near the Colorado River, half of these plots are warmed with infrared lamps to simulate the future.
“Right now, the plots look like sand with confetti colors. So, we’re waiting to see how those communities take shape over time,” says Reed. If the native crusts can’t withstand the expected warming, maybe the crusts already adapted to hotter deserts could.
In the end, perhaps preserving the biocrust’s ecosystem function is more important than preserving species native to the Colorado Plateau.