PARENT SESSION
Oral Session #1: Invasive Species Control.
Presiding: S. Smith
Monday, August 5. 8:00 AM to 11:30 AM. Mohave Meeting Room, TCC.
Development of a weed risk assessment in California.
Stanton, Alison*,1, DiTomaso, Joeseph1, Warner, Peter1, Hall, John2, 1 California Exoctic Pest Plant Council, Berkeley, CA2 The Nature Conservancy, Phoenix, AZ
ABSTRACT- The California Exotic Pest Plant Council (CalEPPC) has developed criteria for ranking the invasiveness of wildland weeds. The ranking process was applied only to non-native plant species that have naturalized in California, and is not a predictive tool for assessing new imports. Three major subsections of criteria were evaluated: 1) impact on natural areas and natural plant communities 2) ecosystem distribution 3) invasiveness (potential to spread). A plant received a score for each of these three categories based on answers to a series of weighted questions. The three scores were then combined to give the plant an overall rank. An additional rank was calculated for management potential that did not contribute to the overall rank. A category was also established indicating the level of documented information on which the ranking was based. Finally, the current range of each species was assessed to determine whether it is widespread in California or more regionally distributed. The results of this ranking process were compiled into a list: Invasive Non-native Plants of Greatest Ecological Concern in California. This new list, and the associated transparent criteria, are a replacement for CalEPPCs Pest Plants of Greatest Ecological Concern, first developed in 1996. The previous list was increasing used in a quasi-regulatory manner to prohibit the sale or installation of invasive plants in local communities and projects through out the state, and it became necessary to establish scientifically defensible criteria for listing. While specific to California, the ranking process was developed in collaboration with several adjacent states. This new weed risk assessment can serve as a template for weed list development in regions within or outside of California.
KEY WORDS: invasive, risk assessment