Virgin River (a tributary of the Colorado) east of St. George Utah

Desert Restoration

Contrary to the popular image, deserts do not consist solely of sand dunes and cacti. In fact bushes and gravel are more typical. Either way, riparian gallery forests along rivers in deserts are an important, if scarce exception to the arid norm. Water is a focal point for humans as well as other species and most of the riparian habitat in the southwest has been lost to development such as agriculture or flooding under reservoirs.

The Colorado River in particular has been highly modified. For over 100 miles of its length in Nevada there is essentially no riparian habitat. It flows out of the Grand Canyon in Arizona, into Lake Mead, then to Lake Mojave, and developed agricultural land by the time it reaches the California border near the town of Needles.

However, development has created some opportunities to generate new riparian habitat as well. Urbanization in the Las Vegas Valley has greatly increased the flow of water down the Las Vegas Wash, which has become a constantly flowing river, draining the valley into what was the Colorado River (now Lake Mead). This has created significant problems of soil erosion and invasion by nonnative water loving species. These challenges are being addressed by the Water Authority planting native riparian species better that are adapted to the changing conditions than the desert shrubs which earlier dominated the site.

Strictly speaking such a project is not restoration, since what is being established is a new and different plant community than what was there previously. Afforestation (establishment of a forest where one did not exist previously) is probably a more accurate description. From a cumulative effects perspective such work has the potential to help compensate regionally for the loss of the Colorado.

The Las Vegas Wash is a big enough project that the nursery I was managing for the National Park Service is not the only supplier, however our operation was small enough that they were our main client. As the park's immediate upstream neighbor, such collaboration serves the interests of both.

The park (Lake Mead National Recreation Area) was the next major consumer, using our material for: mitigation of construction projects within the park; restoration of areas disturbed by unauthorized off-road vehicle usage; and landscaping. Woody riparian plants in particular are needed for shade, and there is a desire to get away from exotic ornamentals. Other government agencies consumed the remainder of our production.

 

 

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Overhanging vegetation

 

Shaded forest floor

 

Edge from inside

 

Edge from outside