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Vegetation of Rio Bosque Wetlands Park

Current vegetation patterns in the park have been greatly influenced by past disturbance, including the channelization of the Rio Grande in the 1930s, past farming of park lands, vehicular traffic over much of the park, and, in 1997, the construction of the wetland cells and water-delivery system.

The construction work in 1997 significantly altered the park landscape. Considerable care was exercised to avoid disturbance of desired native vegetation, but much existing vegetation, including several extensive saltcedar stands, was cleared in the course of creating the wetland cells and water-delivery system.  Approximately 65% of the park was set back to an early successional stage.

Southeast corner of Rio Bosque Park,
23 June 1981

  Southeast corner of Rio Bosque Park,
24 May 2000

Since 1997, as the vegetation has recovered, UTEP and its partners have been working to promote establishment of native plant communities representative of those historically found in the river valley.  In 1999, UTEP established 28 permanent photgraphic stations at the park to document the progress of this effort.  You can view some of the changes since then in the repeat-photography archive

Some areas at the park continue to support early successional vegetation, such as Russian thistle, seepweed, alkali heliotrope, jackass clover, bitterweed, tansy mustard, mountain pepperweed and Indian rushpea. Some areas remain largely barren, with a hardpan soil surface. In spring, bitterweed provides a spectacular floral display as it carpets large expanses in and near the wetland cells.

Approximately 15% of the park supports shrublands dominated by fourwing saltbush, honey mesquite and jimmyweed. These areas were left largely undisturbed during the 1997 construction work.

Another 15% of the park supports woodlands, with tornillo and saltcedar the dominant species. Prior to construction of the wetland cells, dense monotypic stands of saltcedar covered approximately 25% of the park. Much saltcedar was removed in the course of construction. Although several dense stands remain, much of what is now present is interspersed with tornillo. The clearing done in 1997 was not complete, though. In many of the cleared areas, saltcedar has re-sprouted from incompletely removed root systems requiring manual removal or treatment with herbicide.

Approximately 5% of the park supports riparian scrub associations dominated by wolfberry, arrowweed, spiny aster and coyote willow. These associations are best represented near the park perimeter, in areas influenced by the Riverside Canal and the irrigation drains bordering the park.

The best-developed sand dunes in the park are in a small area along the historic river channel. This site, in the southeast part of the park, is the only area where broom psorothamnus, a shrub that favors deep, well-drained sands, grows in the park.

At one time, the City of El Paso maintained a small area in the interior of the park as a tree farm where it grew trees and shrubs for landscaping city parks and other properties. Remnant rows of trees and shrubs are still present in this area, an eclectic mix of native and exotic species very different from the rest of the park.

Grasslands are essentially nonexistent in the park. A few scattered individuals of species such as plains bristlegrass and alkali sacaton are present in upland areas, and species such as barnyardgrass, hare barley and rabbitfoot grass are beginning to invade along the re-built river channel. The park’s large population of black-tailed jackrabbits appears to play an important role in the current scarcity of grasses.

Prior to 2001, the park received water only in fall and winter. There was no opportunity for native wetland or riparian-forest habitat to become established beyond plantings UTEP carried out. Through the cooperation of El Paso County Water Improvement District #1 and El Paso Water Utilities, the park received water all spring and summer in 2001 and 2002. As a result, wetland and riparian plant communities are now beginning to develop along the water-delivery channels and in the wetland cells. Rio Grande cottonwood, Goodding willow, coyote willow and seepwillow are the most conspicuous species becoming established in the riparian zone, with willow baccharis, spiny aster, arrowweed and wolfberry also present. Southern cattail is the predominant emergent plant in the wetland cells and water channels. Other species found along the wetland margins include curltop smartweed, Emory sedge, chufa, barnyardgrass, bearded sprangletop, Mexican sprangletop and inland saltgrass.