Control of Invasive Shrub with Asian Beetles Yields Huge Water Savings

Researchers say an Asian beetle may help control the spread of tamarisk, an invasive Eurasian shrub responsible for water loss across the southwestern United States. After allowing the tamarisk leaf beetle to devour leaves for one year in a 4,500-acre area dominated by the shrub in the Great Basin of Nevada, scientists from the University of California Santa Barbara (UCSB) found that about 2,500 acre-feet of water that would have otherwise been consumed by the plant remained in the ground. “This is roughly the same amount of water that would be used to irrigate 1,000 agricultural acres in a year,” said Tom Dudley, a UCSB biologist. At about $185 per acre-foot, this amount of water could provide annual water needs for 5,000 to 10,000 households, he said. Introduced into North America more than a century ago, tamarisk, also known as saltcedar, now occupies more than a million acres of riverside habitat, displacing native trees, degrading habitat quality for wildlife and exacerbating erosion and sedimentation. The shrub is also flammable, which increases the risks of wildfire.