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San Juan River Near Mexican Hat, Ut

1895

1999

Description:

SAN JUAN RIVER NEAR MEXICAN HAT, UTAH When comparing the ca. 1895 scene to the 1998 retake, the riparian zone has obviously expanded laterally with little apparent change in bank configurations. This expansion suggests that streambanks and floodplains are retaining more subsurface water for longer periods of time. Riparian plant species including Fremont cottonwood, coyote willow, common reed, horsetail, and bulrush have increased in both frequency and total ground cover. Unfortunately, about 50 percent of the total plant composition in the riparian zone consists of exotic species, including tamarisk, Russian olive, camelthorn and Russian knapweed. Upland vegetation has apparently increased as well. Frequencies and density of both shrubs and herbaceous species such as shadscale, blackbrush, Mormon tea, fourwing saltbush, snakeweed, Indian ricegrass and curlygrass have increased. Cheatgrass is also present at this location. This improvement has occurred despite the harsh micro-climate existing here. At such stable state sites, improvements are slow due to poor soil qualities and low percipitation. Some of the same shrubs appear in both photographs.

Photo Information:

Vegetative Community:

Riparian, Black Conifer Brush

Location:

San Juan

January 2018