The scenery of southeastern Utah is hard to miss. Steep redrock canyons plunge into long and lazy riverbends; wind-sculpted stone arches glow pinkly at sunset. But when biologist Jayne Belnap hikes through this famous landscape, it’s not the show-stopping rocks that draw her attention. It’s the algae.
"This is not a rocky
landscape, this is a cyanobacteria landscape — it’s
covered with life," she says. These landlocked colonies of
blue-green algae, she says, are the "skin" of desert soils and many
other surfaces of the planet.
Belnap, a researcher with
the U.S. Geological Survey, has studied the soils of the Colorado
Plateau for the better part of two decades. She is perhaps the
world’s only specialist in biological soil crusts, the living
communities of lichens, mosses, and yes, algae that form dark,
textured soil surfaces in deserts around the world.
humble crusts, sometimes known as cryptogamic or cryptobiotic
crusts, efficiently "fix" nitrogen, converting extraordinary
amounts of atmospheric nitrogen into a form easily used by plants.
Studies by Belnap and others show that the crusts’ structure
also slows wind and water erosion, forming a web of microscopic
roots that holds the soil in place.
biological soil crusts are remarkably resistant to harsh
conditions, Belnap has found that they can be destroyed in an
instant by a wayward boot, hoof or tire. Though such discoveries
have made land-management agencies more mindful of soil crusts,
Belnap’s beloved microflora are far from safe.
The daughter of a prospector, Belnap grew up in
Salt Lake City and spent vacations wandering the backcountry of the
Great Basin and Colorado Plateau. "I spent my childhood smashing
(crusts)," she laughs, "and my dad spent his adulthood running over
them with his bulldozer. I didn’t know any better, and he
didn’t know any better." She studied marine biology at
college in California, then completed a masters’ degree in
community ecology, always preferring to study the workings of
ecosystems rather than individual species.
In the early
1980s, she moved to Moab and landed a job as a seasonal botanist in
Canyonlands National Park. She didn’t think much about soil
crusts until a professor at Brigham Young University, Kimball
Harper, invited her to check out some of his study plots near Grand
Junction, Colo. Harper had measured greater water runoff and
erosion in grazed watersheds than ungrazed watersheds, and he
thought the difference was due to the soil-grasping crusts. Though
biologists had studied the composition of crusts, Harper was the
first to take a serious look at their role in the ecosystem.
Belnap, impressed by the potential importance of the
crusts, says she got "pulled down into the dirt." Harper became her
Ph.D. advisor, and by 1988, she was a full-time soil-crust
researcher for the Park Service. She investigated the
nitrogen-fixing abilities of the crusts, then moved on to studies
of the crusts’ substantial resistance to wind erosion.
By the late 1980s, Belnap and her coworkers had found
that crusts were extremely vulnerable to crushing, and very slow to
recover from human and livestock disturbance. Though cyanobacteria
return to a disturbed area in a matter of months, the researchers
estimated that the mosses and lichens — the most effective
nitrogen fixers — do not return to full strength for 250
years or even more.
The Park Service reacted quickly to
this news. These days, visitors to national parks in the region are
routinely and emphatically warned not to "bust the crust," and
it’s common to see hikers weaving carefully through the
desert: "They look like they’re drunk," jokes Walt Dabney,
who served as the superintendent of Canyonlands and Arches national
parks from 1991 to 1999. What’s more, federal land-management
agencies usually consider effects on biological soil crusts in
their environmental analyses of proposed Colorado Plateau projects.
Despite the substantial impact of
Belnap’s data, the long-term prognosis for soil crusts is not
good. Though the Park Service keeps a close eye on its visitors,
the Bureau of Land Management land that surrounds Moab hosts tens
of thousands of much more loosely regulated hikers, mountain
bikers, and off-road vehicle enthusiasts every year. Grazing
continues in the low-lying areas favored by soil crusts, and the
Bush administration has helped fuel a renewed push for oil and gas
drilling in the deserts of southeastern Utah (see story next
Though Belnap is forceful and fearless in her
arguments for the ecological importance of soil crusts, she says
such highly political land-management wrangles need nuanced
solutions. For instance, while grazing at low elevations almost
certainly takes a major toll on crusts, grazing at higher
elevations might not have such heavy impacts.
says that good management decisions require a wide-ranging and open
debate. "Science is only a part of the discussion," she says.
"There are cultural voices, economic voices, there are these other
voices as well, and they need to be listened to."
the one powerful thing science can do is that it can tell you about
the true bottom line," she adds. "And the true bottom line is that
if you use up the resources that your economics and culture are
based on, you’re going to have to move."
what she calls her "herd" of seasonal and permanent co-workers
recently shifted their shop from the Park Service to the biological
research arm of USGS, a switch that has allowed Belnap to
participate in soil-crust research in Australia, Africa and even
Iceland. She’s currently studying the effect of crusts on
water erosion and exotic plant invasions, and looking at the effect
of climate change on crust recovery.
She also remains
convinced that the dark shadows on the desert are the true —
and fragile — foundation of the Colorado Plateau. "Whenever
we pull on the thread of what makes the system tick," she says, "we
end up with soil crusts on the other end."