2nd National Extension Nat Res Conference-Abstract 63

Susan Donaldson, University of Nevada Cooperative Extension, PO Box 11130, Reno, NV 89520; 775.784.4848; sdonalds@agnt1.ag.unr.edu and Sherman Swanson, University of Nevada Cooperative Extension, Mail Stop 186, Reno, Nevada 89557; 775.784.4057; sswanson@agnt1.ag.unr.edu

Triage is a concept first practiced by military medics during crisis situations. On a battlefield, medics ignore the wounded that will recover without help, and they let dying patients die. Their limited time and resources are put to saving the wounded that can be saved only with immediate help. This same concept can be applied to weed management to help us prioritize our efforts during crisis. Applying triage early is often the only real opportunity to prevent harmful changes in vegetation and/or biodiversity.

Such an opportunity arose in the Lake Tahoe basin in 1997 when the first instance of the noxious weed tall whitetop (Lepidium latifolium) was documented in Incline Village, Nevada. Tall whitetop is a non-native weed from Eurasia that has invaded sensitive wetland and riparian sites in the western United States. The unchecked invasion of riparian areas along the Truckee River east of Reno raised concerns that similar areas at the lake could also be lost to tall whitetop, with resultant increases in erosion due to its non-fibrous root system and impairment of water quality. Current research suggests that the lake is phosphorus limited, with erosion and sediment transport increasing phosphorus loads to the lake. Researchers agree that limiting erosion and sediment inputs into the lake is essential to limiting further losses in lake clarity.

An effort was begun immediately to locate and map the weed throughout the Basin. Following a coalition-building training in April 1998, a public awareness campaign was mounted. Local media ran stories on radio, television, and in local newspapers, and posters were placed in strategic locations. The public was asked to call and report suspected locations of the weed. From these reports, 35 tall whitetop-infested sites were confirmed and mapped. Eight more sites were documented in 1999. Many sites fall within priority 1 and 2 watersheds critical to preserving the Lake?s water clarity. At numerous locations, there is a co-incidence of straw bale usage and tall whitetop infestation, suggesting seeds or plant parts are entering via these erosion-control bales.

The current phase involves the implementation of site-specific control methods by a partnership consisting of El Dorado County, California Department of Food and Agriculture, Nevada Cooperative Extension, and Tahoe Regional Planning Agency. Local residents have volunteered to ?Adopt-a-Spot? for weed pulling and long term monitoring of control efforts. As the Lahontan Regional Water Quality Control Board has set a zero tolerance standard for pesticides in Lake Tahoe water, their approval was obtained prior to chemical applications during the summer of 1999. Approximately 90-95% of all plants in Nevada and approximately 60% in California were treated with herbicides, with the remainder being hand pulled. Agencies and local citizens donated all materials and labor required. The highly successful partnership has allowed us to apply the concept of triage in our attempts to eradicate this noxious weed from the Basin and protect the Lake?s famous water quality.