EM1

          
                    Typical crust at site 1                                                  View at site 1

Mojave National Preserve, San Bernardino County, California, USA.  35º 11.671' N, 115º 52.223' W, 2100 feet elevation. 14.4 miles east southeast on Kelbaker Road, 0.6 miles east of EM2, the first lava flow close to the road. On north side of road between a small shack and a highway sign (before bend in road), between the road and a broad wash.  Date of sampling: 4 June 1998


Dominants vascular plants in the site:  Ambrosia dumosa, Cryptantha angustifolia, Larrea tridentata, Schismus arabicus.

Other common vascular plants:  Atriplex canescens, Chorizanthae rigida, Eriogonum tricopes, Hymenoclea salsola, Opuntia bacillaris, Opuntia ramosissima, Senna armata.

Mean algal crust thickness: 7.4 mm
Mean lichen crust thickness: 12.2 mm

Cover summary:

Type Cover        % Cover
Shrubs                       0.0
Annuals                   16.4
Perennial grasses     0.0
Perennial forbs         0.0
Algal crust               48.8
Bryophytes                0.0
Lichens                     24.8
Bare Soil                     0.8
Rock                            0.4
Gravel                         8.4
Litter                           0.4
Cactus                         0.0

       
Chlorophyll a (ng/g):  5466.11
N fixation rate (mmol n2/m2/hr): 18319.98
Soil texture class:  loamy sand

EM2

        
                Typical crust at site 2                                                    View at site 2

Mojave National Preserve, San Bernardino County, California, USA.   35º 12.200' N, 115º 52.184' W, 2100 feet. elevation.  Cindercone site, 13.8 miles east southeast on Kelbaker Road, the first lava flow close to the road. On north side of road up on the lava flow, only inter-rock spaces with visible crust were sampled.   Date of sampling:  7 June 1998.

Dominants vascular plants at the site:  Larrea tridentata, Lycium andersonii, Polygonum ovata, Schismus arabicus, Yucca schidigera

Other common vascular plants:  Ambrosia dumosa, Atriplex hymenelytra, Chorizanthae rigida, Dalea mollis or D. mollissima, Oligomeris linifolia, Opuntia bacillaris, Opuntia ramosissima

Mean algal crust thickness: 8.0 mm
Mean lichen crust thickness: 14.0 mm

Cover summary:

Type Cover        % Cover
Shrubs                        0.4
Annuals                   14.4
Perennial grasses     0.0
Perennial forbs         0.0
Algal crust              33.2
Bryophytes               0.4
Lichens                    17.2
Bare Soil                    0.0
Rock                         26.4
Gravel                        6.4
Litter                          1.6
Cactus                        0.0

Chlorophyll a (ng/g):  8262.64
N fixation rate (mmol n2/m2/hr): 5683.55
Soil texture class:  sandy loam

EM3

                        View at site 3

Mojave National Preserve, San Bernardino County, California, USA.  35º 27.113' N, 115º 40.550' W, elevation 3500 feet.  Cima Road exit off I-15, north side of I-15, east side of Cima Road.  Gypsiferous soil, sampled top of closest hill.   Date of sampling: 6 June 1998.

Dominants vascular plants at the site:  Atriplex confertifolia, Ephedra nevadensis, Larrea tridentata

Other common vascular plants:  Acamptopappus sp., Ambrosia dumosa, Ceratoides lanata, Descurania pinnata, Encelia virginensis, Hillaria jamesii, Krameria erecta, Lepisium fremontii, Lycium andersonii, Menodora spinescens, Stanleya pinnata

Mean algal crust thickness: 12.1 mm (8 crusts)
Mean lichen crust thickness: 17.0 mm (2 crusts)

Cover summary:

Type Cover        % Cover
Shrubs                       0.0
Annuals                    0.0
Perennial grasses    0.0
Perennial forbs        0.0
Algal crust             87.2
Bryophytes              0.0
Lichens                   12.0
Bare Soil                   0.4
Rock                          0.0
Gravel                       0.0
Litter                         0.4
Cactus                       0.0

Chlorophyll a (ng/g):  113.70
N fixation rate (mmol n2/m2/hr): 9058.11
Soil texture class:  

EM4

  
                        View at site 4                                                       Typical crust at site 4

Mojave National Preserve, Granite Mountain Research Station, California, USA.  34° 47.316' N latitude, 115° 39.229' W longitude.  Small valley area above Hidden Valley, many crusts.  Date of sampling: 7 June 1998.

Dominants vascular plants at the site:  Shrubs, Cholla "imbricata", Pinyon pine, Echinocactus, Ephedra, Opuntia (yellow spine).  

Other common vascular plants:  Bromus tobrus (B. madritenses ssp. rubens), Pursia tridentata, Chrysothamnus, Coleogyne ramosissima, Eriogonum.  

Mean algal crust thickness: 
Mean lichen crust thickness: 

Cover summary:

Type Cover        % Cover
Shrubs                       0.0
Annuals                    3.6
Perennial grasses    0.0
Perennial forbs        0.0
Algal crust              12.4
Bryophytes             19.6
Lichens                      7.6
Bare Soil                  27.6
Rock                          1.6
Gravel                      10.0
Litter                         3.6
Cactus                       0.0
Sand                         14.0