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Land and People:
Conserving the Surroundings of Rock Art
Dorde W. Woodruff
Cryptobiotic Soil
"Now to look at arid and semi-arid lands in more detail. A peculiar characteristic of all the
world's deserts is cryptobiotic (meaning "hidden life") soil, a crust on top of the ground
composed of a mixture of cyanobacteria (formerly called blue-green algae), several different
types of algae (Flechtner et al.1998:296), fungi, lichens (which are themselves symbiotic
organisms composed of algae and fungi), mosses, and sometimes liverworts or diatoms."
"The original name for this mixture of organisms, cryptogamic soil, is from an old botanical term
for primitive plants without flowers, cryptogam, meaning "hidden marriage" or "hidden gametes",
gametes being the reproductive parts; before microscopes the reproductive phase of these plants
was hidden from human view. Other terms used are microphytic, "small plant", and microbiotic,
"small life". There is no referee or dictator, so researchers use their favorite term."
"Cryptobiotic soil is quite important to desert ecology, yet easily damaged. It's not easy anymore
to find a complete cover of cryptobiotic soil between the scattered shrubs, herbs, and grasses of the
desert. ..."
"For a long time cryptobiotic soil was overlooked; study of its ecology is fairly recent. The
landmark fieldwork of Ed Kleiner and Kimball Harper in Canyonlands in 1967 and 1968 (Kleiner
and Harper 1972) demonstrated basic differences between grazed and ungrazed areas. They
compared Virginia Park, a grassy place surrounded by rock walls and accessible only through a
unique, steep, rocky tunnel through the sandstone wall, to adjacent Chesler Park which had been
grazed for many years in winter by horses, while only deer and no domesticates could get into
Virginia Park."
"Cryptobiotic cover was about seven times greater in Virginia Park (above), and it was much
richer floristically than Chesler, with more grasses and fewer shrubs. Without pressure from domestic grazers, cacti were less spiny. The soil had more nutrients. There was no drainage channel erosion. The vegetation formed a pattern, indicative of diversity and therefore productivity (Siegel 1999). The soil texture was finer. They concluded that the intact cover of cryptobiotic soil contributed to soil nutrients, and stabilized the soil to resist water and wind erosion."
"In another landmark study Evans and Ehleringer (1993), using a new and more effective method
of measurement, found that cryptobiotic soil was the primary source of nitrogen for desert soil.
Some of the organisms of this crust, especially cyanobacteria, can change gaseous nitrogen from the air to a form usable by plants. In deserts water is the most limiting factor to plant growth, but
nitrogen is second. Cryptobiotic crusts also increase water infiltration and retention, holding it for
use, limiting runoff and its concomitant erosion. They enhance the establishment of seedling plants,
and warm the soil (Utah Bureau of Land Management, Monticello, 1999)."
"These small organisms may look insignificant. They are not. All this is helpful and even essential to the health of deserts. But cryptobiotic crusts are fragile, and all the more so when it is hot and dry and they are dormant and brittle. When Kleiner and Harper returned to Virginia Park in the second year of their study, they were surprised their footsteps were still so visible. After that they walked in the same paths. People, domestic or wild animals, vehicles, bicycles, and wildfires all impact the crust (Buttars et al., 1998)."
"Recovery rates are slow. The organisms grow only when wet; summer heat and drought inhibit
them. Estimates vary, but ecologist Jayne Belnap thinks that ground left bare is vulnerable for at least 20 years after disturbance (Belnap 1997). If soil is then lost it may take up to 10,000 years to form again. Time for recovery of the different species varies. Cyanobacteria may begin to recover in as little as six months and may be healthy in five years (Allen 1999). But Belnap notes that it may take at least 50 years for nitrogen fixation to completely return. Furthermore, "assuming adjoining soils are stable and rainfall is average, recovery rates for lichen cover in southern Utah have been most recently estimated at a minimum of 45 years, while recovery of moss cover was estimated at 250 years.""
"Of course, trampling of any kind disrupts or kills other organisms large and small besides the
cryptobiotic ones (National Park Service, Arches 1996) but these small crust organisms are less likely to be noticed. In the photo at left, sand from disturbance blew over these cryptogams and will kill them. Note the micro-topography; the uneven surface helps water absorption into the ground, helping to prevent runoff."
Reference: Excerpted from the PDF - Utah Rock Art -Volume XIX, Papers presented at the Nineteenth Annual Symposium of the Utah Rock Art Research Association (URARA) Vernal, Utah, September 1999 - pages 87-100 "Land and People: Conserving the Surroundings of Rock Art" by Dorde W. Woodruff - ©2000, 2002 by the Utah Rock Art Research Association (U ), Salt Lake City, Utah. All rights reserved. Printed in the United States of America on acid-free paper. http://www.utahrockart2.org/pubs/proceedings/volumes/Proceedings_Utah_Rock_Art_Volume_19.pdf
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