Biological Soil Crusts:

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Biological Soil Crusts

• Keystone of the Colorado Plateau

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Keystone Species

• Cyanobacterium Microcoleus vaginatus

Figure 1. Filaments of Microcoleus vaginatus (x
3000), the dominant organism in the crust.
Individual cells abut each other to form the
filaments.
from http//geochange.er.usgs.gov/sw/impacts/biol
ogy/crypto/
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Microcoleus
Figure 3. Microcoleus filaments (lower left) emerging from mucilagenous sheath (upper right). Scale bar is 10 micrometers.
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How is this a keystone species??
Figure 4. Crust in sandy soils. The visible fibers are Microcoleus vaginatus. Note how Microcoleus connects the otherwise loose sand grains together, thus preventing wind and water erosion. Microcoleus is important in enhancing water and nutrient relations within the soil, as well. Scale bar is 100 micrometers.
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Cryptobiotic Soil Crusts
Open spaces covered by biological soil crusts, a
highly specialized community of cyanobacteria,
mosses, and lichens.
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Cryptobiotic Soil Crusts

• Protection for plant seedlings

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Cryptobiotic Soil Crusts

• Protection from erosion

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Cryptobiotic Soil Crusts

• Easily destroyed by trampling, off-road vehicles,
  etc.

ORVs in the Indian Creek area travel off-route at
nearly every opportunity they have. Here, illegal
cross-country riding has crushed cryptobiotic
soils, causing damage that could last 50 to 300
years. Indian Creek proposed wilderness area. San
Juan County, UT. redrockheritage.org/orv_gallery_2
/