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Ranking Nonindigenous Weed Species by Their Potential to Invade the United States

  • Chris Parker (a1), Barney P. Caton (a2) and Larry Fowler (a2)

Because of the large number of potentially invasive species, and the time required to complete weed risk assessments (WRAs) with the use of the current, mandated system in the United States, species need to be prioritized for assessment and possible listing as Federal Noxious Weeds. Our objective was to rank the potential invasiveness of weedy or pest plant species not yet naturalized in the United States. We created a new model of invasiveness (hereafter the U.S. weed-ranking model) based on scoring factors within four elements: (1) invasiveness potential, or likelihood to exhibit invasive behavior; (2) geographic potential, or habitat suitability; (3) damage potential, or likely impact; and (4) entry potential, or likelihood to be introduced. The ranking score was the product of the four elements. We scored 250 species satisfactorily, from a list of 700 +. We analyzed model sensitivity to scoring factors, and compared results to those from a WRA model for Hawaii. For species not in cultivation in the United States, the top 25 species included a mix of annuals, perennials, sedges, shrubs, and trees. Most had exhibited invasive behavior in at least several other countries. Because of greater entry potential scores, the highest-scoring species were weeds in cultivation. Twenty-nine such species, out of 44 total, had scores greater than the highest scoring species not in cultivation. In comparison to the Hawaii WRA model, correlation and regression analyses indicated that the U.S. weed-ranking model produced similar, but not exact, results. The ranking model differs from other WRAs in the inclusion of entry potential and the use of a multiplicative approach, which better suited our objectives and United States regulations. Two highly ranked species have recently been listed as Federal Noxious Weeds, and we expect most top-tier species to be similarly assessed.

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C. C. Daehler and D. A. Carino 2000. Predicting invasive plants: prospects for a general screening system based on current regional models. Biol. Invasions. 2:93102.

C. C. Daehler , J. S. Denslow , S. Ansari , and H. Kuo 2004. A risk assessment system for screening out invasive pest plants from Hawai'i and other Pacific Islands. Conserv. Biol. 18:360368.

B. J. Goodwin , A. J. McAllister , and L. Fahrig 1999. Predicting invasiveness of plant species based on biological information. Conserv. Biol. 13:422426.

R. P. Keller , D. M. Lodge , and D. C. Finnoff 2007. Risk assessment for invasive species produces net bioeconomic benefits. Proc. Natl. Acad. Sci. U.S.A. 104:203207.

C. S. Kolar and D. M. Lodge 2001. Progress in invasion biology: predicting invaders. Trends in Ecology and Evolution. 16:199205.

C. E. Mitchell and A. G. Power 2003. Release of invasive plants from fungal and viral pathogens. Nature. 421:625627.

H. Muller-Scharer , U. Schaffner , and T. Steinger 2004. Evolution in invasive plants: implications for biological control. Trends Ecol. Evol. 19:417422.

P. C. Pheloung , P. A. Williams , and S. R. Halloy 1999. A weed risk assessment model for use as a biosecurity tool evaluating plant introductions. J. Environ. Manag. 57:239251.

D. Pimentel , L. Lach , R. Zuniga , and D. Morrison 2000. Environmental and economic costs of nonindigenous species in the United States. BioScience. 50:5364.

S. H. Reichard and W. H. Hamilton 1997. Predicting invasions of woody plants introduced into North America. Conserv. Biol. 11:193203.

M. Rejmanek and D. M. Richardson 1996. What attributes make some plant species more invasive? Ecology. 77:16551661.

D. M. Richardson , P. A. Williams , and R. J. Hobbs 1994. Pine invasions in the southern hemisphere: determinants of spread and invadability. J. Biogeogr. 21:511527.

J. Roy 1990. In search of the characteristics of plant invaders. Pages 335352. in F. Di Castri , A.L. Hansen , M. Debussche eds. Biological Invasions in Europe and the Mediterranean Basin. Dordrecht, The Netherlands Kluwer.

K. Skinner , L. Smith , and P. Rice 2000. Using noxious weed lists to prioritize targets for developing weed management strategies. Weed Sci. 48:640644.

C. Smith , W. Lonsdale , and J. Fortune 1999. When to ignore advice: invasion predictions and decision theory. Biol. Invasions. 1:8996.

J. Whinam , N. Chilcott , and D. M. Bergstrom 2005. Subantarctic hitchhikers: expeditioners as vectors for the introduction of alien organisms. Biol. Conserv. 121:207219.

D. Wilcove , D. Rothstein , J. Bubow , A. Phillips , and E. Losos 1998. Quantifying threats to imperiled species in the United States. Bioscience. 48:607615.

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Weed Science
  • ISSN: 0043-1745
  • EISSN: 1550-2759
  • URL: /core/journals/weed-science
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