Giant Reed (Arundo donax) Control in
Southern California Riparian Systems:
Dealing with a Process-altering System-level Invasive Weed

* Presented at Southern California Botanists Annual Meeting on 22 October 1994 at California State University Fullerton *

Gary P. Bell
The Nature Conservancy
Temecula, California

Invasive alien weeds may interact with natural ecosystems in various ways, they may have no significant impact, they may have direct competitive or allelopathic interactions with individual native species or groups of species, or they may have complete, sytemic impacts, altering the very structure and natural process of the community into which they have invaded. Giant Reed (Arundo donax), the worlds's largest grass, is an example of this later type of weed. By virtue of its growth characteristics, adaptations to disturbance (especially fire), its lack of natural predators and competitors in North America, and its unsuitability as food or habitat for native wildlife, giant reed has established itself as one of the primary threats to native riparian habitats in the western United States. Because giant reed does not provide either food or habitat for native species, areas it has taken over are depauperate of wildlife. The Santa Ana River Arundo Management Task Force, a coalition of twenty local, state and federal agencies and private organizations working together under the banner of "Team Arundo", formed in 1992 to find weapons and protocols for defeating the giant cane. The efforts of "Team Arundo" may serve as a model for other multi-party efforts to deal with system-level weed invasions.