PARENT SESSION
Oral Session # 55: Resource Management II: Terrestrial Systems.
Presiding: E Latty
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 106.
Predicting pest plants in Hawaii and other tropical Pacific islands.
Denslow, Julie1, Daehler, Curt2, Ansari, Shahin2, Kuo, Huang-Chi2, 1 USDA Forest Service, Hilo, HI2 University of Hawaii, Honolulu, HI
ABSTRACT- More than 1000 species of non-native plants have naturalized in the Hawaiian Islands. While only a small proportion cause significant ecological harm to native ecosystems, most that do were intentional introductions and often are still in the commercial plant trade. We sought a mechanism to rapidly and efficiently evaluate exotic species for potential invasiveness on tropical islands. Oceanic islands are particularly vulnerable to establishment of exotic pests and thus present a challenge to effective screening programs. We adapted the Australian Weed Risk Assessment protocol for use in tropical high islands. This system uses 49 questions about plant invasive behavior where introduced elsewhere, life history traits, and climate suitability to develop an index of invasiveness. We evaluated 172 non-native species long in the trade in Hawaii and the Pacific and selected to represent a wide range of plant families and growth forms. Independently we solicited the expert evaluations of 25 botanists with extensive field experience in the tropical Pacific. The system returned clear evaluations for 76% of the species submitted. Addition of a secondary screen to evaluate undecided species increased the percent evaluated to 92%. Agreement with expert opinion was high: 95% of major pest plants, 67% of minor pests, and 76% of non-pests of native ecosystems were correctly identified. Information on invasive status elsewhere was an important component of the screen, but by itself identified only 81% of major pests. Invasive behavior in native and managed ecosystems were significantly correlated. We suggest that this system can be a useful tool to rapidly evaluate large numbers of actual and potential introductions of plants for their potential pest status.
Key words: risk assessment, invasive species, Hawaii