Wanted: unclogged rivers

Scientists and natural resources policymakers converge in Davis, Calif., this week to discuss their assassination plot against a serial killer: Arundo donax. This giant reed grows mostly in the Central Valley and Southern California, where it is choking sections of the Santa Ana and Ventura rivers. But the invasive plant is also terrorizing the Russian River watershed, which is home to three salmon species listed as federally threatened. Arundo displaces native trees and shrubs that provide shade and the cool water salmon need to thrive. Tree root systems also act as sieves to protect waterways from pollutants and heavy sediment. Restoration specialists have used aerial photography and a computerized graphic information system to map the plant’s location -- 250 acres along the main stem of the Russian River and an additional 750 acres in spot locations. The price tag: about $3 million, says restoration ecologist Karen Gaffney, a figure that grows daily as arundo marches on. “Tarping” the reed with plastic sheeting for up to five months is the most effective way to get rid of it, she says. A workshop about arundo and other invasive species is scheduled for Saturday morning at the four-day 22nd Salmonid Restoration Conference. Other topics include the effect of climate change on salmon recovery and urban creek restoration. Go to www.calsalmon.org/conference.html.