In the high desert of Utah, at a research site about 20 miles outside of Moab, Deborah Neher tries to step on the bushes. She doesn’t want to hurt the soil. Or, rather, what lives on top of the soil: an inch-high layer of lichens, mosses, tiny fungi, cyanobacteria, and microscopic creatures described by Neher as "darn fragile."
"That’s a living community," says Neher, chair of UVM's department of plant and soil science, of the biological soil crust. Although they’re little known, biological crusts cover a lot of the planet. They dominate many of the dry places that comprise about 35 percent of global land area from Africa to the polar regions.
Soil crusts form a living mulch, sponging up what little rain falls as well as other important air elements. Neher and her colleagues want to know what climate change is doing to these crusts. Rising temperatures might not seem like a problem in a desert, but their research suggests that increasing summer heat in the Southwest kills important species of mosses, lichens and bacteria in the soil crust. And this, in turn, reverberates throughout desert ecosystems.
The general conclusion thus far? "With climate change, we’ll have more sparse desert communities, with fewer native shrubs and grasses," Neher says. And this threat — combined with other factors — "means we’re likely to see more dust and erosion like we saw during the Dust Bowl days in the 1930s," she says. Neher says that along with measuring crust damage, they can also detect surprising changes to the "amazing and strange little critters" that live in and under the crust: mites, springtails, nematodes, and protozoa.
Neher, her technician and graduate students spend a great deal of time peering into microscopes and cataloging who lives in a soil crust and how they make a living. "We have to know the basic natural history to answer our ecological question," Neher says, "First we have to know how soil crusts function to really understand how climate change is changing that function."