Athel (Tamarix aphylla) and Athel hybrid (Tamarix aphyllaX Tamarix ramosissima)Establishment and Control at Lake Mead National Recreation Area

摘要

Athel is a large evergreen ornamental tree that has been planted throughout the Southwest since the 1950’s. Athel was considered benign because it was thought to produce non-viable seed unlike its invasive relative, tamarisk. However, athel began establishing in the wild from seed on Lake Mead in 1983. Lake Mead NRA has been actively controlling athel since November 2004 along the high water mark of Lake Mead shoreline (439 miles) to prevent it from spreading throughout the Colorado River Drainage. The NPS contracts Nevada Conservation Corp crews and the Lake Mead Exotic Plant Management Team to implement the control efforts of athel and the hybrid. Since 2004 Lake Mead NRA has controlled 72,156 athel and 11,749 hybrids. Control methods have been effective and follow up monitoring and retreatment is planned during the 2009 field season. Based on observations at Lake Mead NRA, the invasive potential of athel is high, particularly in light of its hybridization potential with tamarisk thus creating a new noxious weed. Natural resource land managers should be vigilant in monitoring current athel populations to ensure they do not become invasive or hybridize with tamarisk.