Invasive Species

Much of the plant life that you find in the Wash today is NOT native to the area. Comprising approximately 1,500 acres, invasive weeds such as Tamarisk (Tamarix ramosissima) AKA salt cedar, has established in the system, invading the native plant communities in the Wash system.

Tamarisk (Tamarix ramosissima)	Giant reed (Arundo donax)

The problem with tamarisk and other invasive species is that they come from another country and their natural predators that keep their populations in check in their native habitat are not present in the newly colonized area. This enables them, if they become established, to thrive and reproduce virtually without natural opposition, unlike the native plants that still face their natural predators. Invasive weeds displace native plants, forming monocultures of a single weed species, and are usually less desirable to fish and wildlife not to mention farmers and recreation enthusiasts. In the United States alone, more than 890 million acres of land have been infested with invasive plants, degrading habitat and agricultural land, impacting recreational and cultural resources, and other natural resources with a billion dollar cost for weed related controls and loss of land.

Tall whitetop infestation

To address the weed issues in the Las Vegas Wash, the Las Vegas Wash Coordination Committee (LVWCC) initiated the formation of the Las Vegas Wash Weed Partnership in June 2002. This multi-agency group has targeted three priority weeds for management, tall whitetop (Lepidium latifolium), giant reed (Arundo donax) and tamarisk as well as identified a number of other invasive plants for the Watch Weed List to be addressed in the future.

The Las Vegas Wash Integrated Weed Management Plan was developed to guide the weed program and an aggressive control program is underway to tackle the three priority weeds. Crews from the National Park Service's Exotic Plant Management Team conduct treatments 2-3 times per year throughout the Wash and crews from Clark County's Vector Control, Parks and Recreation and LVWCC tackle these and other weeds along the Wash and Wetlands Park.

A collaborative weed management effort on the Wash has many benefits. Managing weeds helps support the plant diversity in the Park as well enhance habitat for the fish and wildlife. By maintaining less than 20% encroachment of invasive plants on the revegetation sites for the grade control structures, the LVWCC meets the requirements set by the US Army Corps of Engineers 404 permits for mitigation. By reducing the weeds in the Wash, we help to reduce the source of weeds to downstream Lake Mead and Lower Colorado River. For more information on the weed management program on the Wash visit the Invasive Species Management section.