JT1

  
               View of site 1 (Pinto Basin)                                      Typical crust at site 1

Joshua Tree National Park, Pinto Basin, Riverside County, California, USA.   33° 52.945' N latitude, 115° 43.930' W longitude.  Four miles down Old Dale Road, east side of road.  Date of sampling:  8 June 1998.

Dominants vascular plants at the site:  Cheesebush, Chorizanthae (disarticulating type), Larrea tridentata

Other plants:  Eriogonum sp. (delicate), Opuntia bigelovii, Opuntia ramosissima, Sarcostemma cyanchoides ssp. hartwegii, Schismus sp., Desert monkeyflower (magenta flower), Smoke tree (spotted pods, spiny blue-green thing)

Mean algal crust thickness (all 10 samples): 4.1 mm

Cover summary (Preferentially sampled high algal crust areas, counts not representative of the whole area.):

Type Cover                % Cover
Shrubs                              0.0
Annuals                           9.6
Perennial grasses           0.0
Perennial forbs               0.0
Algal crust                     60.0
Bryophytes                      0.0
Lichens                             0.0
Bare Soil                         20.0
Rock                                 0.8  
Gravel                              9.6
Litter                                0.0
Cactus                              0.0

Chlorophyll a (ng/g): 4860.26
N fixation rate (mmole/n2/m2/hr):  3649.16
Soil texture class:  sandy loam

JT2

  
                   View of site 2 (Cadiz Valley)                               Typical crust at site 2 

Joshua Tree National Park, Cadiz Valley, San Bernardino Co., California, USA.   34° 06.592' N latitude, 115° 28.821' W longitude.  Area where restoration efforts are underway, south of Highway 62, east of Clark Pass. There is a large pull out, with the dirt road heading out of the pull out closed by the National Park Service. The study area was about 400 meters south of the pull out in a large flat area which may pond during heavy rains. Surface is covered with coarse sand and gravel which is subtended by a finer soil.  Date of sampling:  8 June 1998.

Dominants vascular plants at the site: Larrea tridentata, Ambrosia dumosa, Schismus barbatus

Other plants:  Chorizanthae rigida, Encelia sp. (frutescens or actoni), Petalonyx thurberi, Polygonum ovatum

Mean algal crust thickness: 6.2 mm
Mean lichen crust thickness: 12.6 mm

Cover summary:

Type Cover                    % Cover
Shrubs                                 0.0
Annuals                             12.0
Perennial grasses               0.0
Perennial forbs                   0.0
Algal crust                         69.2
Bryophytes                          0.0
Lichens                               12.0
Bare Soil                               2.0
Rock                                      0.0
Gravel                                   4.4
Litter                                     0.4
Cactus                                   0.0

Chlorophyll a (ng/g):  4165.94
N fixation rate (mmole/n2/m2/hr):  8647.22
Soil texture class:  loamy sand

JT 3

Joshua Tree National Park, Joshua Tree Forest, San Bernardino County, California, USA.  34° 02.545' N latitude, 116° 10.952' W longitude.  Date of sampling:  9 June 1998.