NB-1

Natural Bridges, Garfield County, Utah, USA.   37° 36.699’ N latitude, 110° 00.516’ W longitude, elevation 6057 ft. Relatively shallow reddish soils underlain by slickrock, Mesa Trail from Sipapu Bridge trailhead. We went up a small channel to the left to avoid footprints. Date of sampling: 14 May 1999.

Dominant vascular plants at the site: Pinus edulis, Juniperus osteosperma, Gutierrezia sarothrae, Yucca harrimaniae, broad-leaf yucca

Mean lichen crust thickness: 27.4 ± 6.8 mm
Mean algal crust thickness: 26.8 ± 7.1 mm

Cover summary:

Type Cover          % Cover
Shrubs                          0.0
Annuals                       0.4
Perennial grasses       0.0
Perennial forbs           0.0
Algal crust                 80.8
Bryophytes                  0.8
Lichens                       10.4
Bare Soil                       0.4
Rock                              1.2
Gravel                           3.2
Litter                             2.8
Cactus                           0.0

Chlorophyll a (ng/g):  285.81
N fixation rate (mmol/n2/m2/hr):  4882.29
Soil texture class:  sandy loam

NB-2

Natural Bridges, Garfield County, Utah, USA.  37° 35.937’ N latitude, 110° 01.742’ W longitude, elevation 5952 ft. Relatively shallow reddish soils underlain by slickrock, Kachina Bridge Trail, first ledge up from the bottom of the stream bed. Date of sampling: 14 May 1999.

Dominant vascular plants at the site: Pinus edulis, Juniperus osteosperma, Gutierrezia sarothrae, Ephedra viridis, Yucca angustissima.

Mean lichen crust thickness: 34.0 ± 9.4 mm
Mean algal crust thickness: 29.6 ± 14.9 mm

Cover summary:

Type Cover           % Cover
Shrubs                          0.8
Annuals                       0.0
Perennial grasses       0.0
Perennial forbs           0.0
Algal crust                 66.4
Bryophytes                  2.0
Lichens                       16.8
Bare Soil                       8.8
Rock                              0.0
Gravel                           0.4
Litter                             4.8
Cactus                           0.0