© 2007 The Authors DOI: 10.1111/j.1472-4642.2007.00381.x Journal compilation © 2007 Blackwell Publishing Ltd www.blackwellpublishing.com/ddi 633 Diversity and Distributions, (Diversity Distrib.) (2007) 13, 633–644 BIODIVERSITY RESEARCH ABSTRACT Effective management of introduced species requires the early identification of species that pose a significant threat of becoming invasive. To better understand the invasive ecology of species in New England, USA, we compiled a character data set with which to compare non-native species that are known invaders to non-native species that are not currently known to be invasive. In contrast to previous biological trait-based models, we employed a Bayesian hierarchical analysis to identify sets of plant traits associated with invasiveness for each of three growth forms (vines, shrubs, and trees). The resulting models identify a suite of ‘invasive traits’ highlighting the ecology associated with invasiveness for each of three growth forms. The most effective predictors of invasiveness that emerged from our model were ‘invasive elsewhere’, ‘fast growth rate’, ‘native latitudinal range’, and ‘growth form’. The contrast among growth forms was pronounced. For example, ‘wind dispersal’ was positively correlated with invasiveness in trees, but negatively correlated in shrubs and vines. The predictive model was able to correctly classify invasive plants 67% of the time (22/33), and non-invasive plants 95% of the time (204/215). A number of potential future invasive species in New England that deserve management consideration were identified. Keywords Bayesian, biological invasions, dispersal, invasive species, latitudinal range, life history, plant ecology, shade tolerance. INTRODUCTION Invasive plants can alter plant community structure and ecosystem function (Vitousek et al., 1987), result in large economic costs from lost ecosystem services (Pimentel et al., 2005), and detract from an intrinsic or aesthetic value associated with native biodiversity and native plant dominance. The threat posed by non-native invasive plant species has spurred efforts to identify individual species that show a high probability for naturalization and/or invasiveness and to rapidly eradicate those species while their distributions are limited or prevent their introduction. Identifying suites of plant traits and corresponding ecological strategies used by successful invaders would improve our understanding of how particular species and landscape features interact to produce the explosive spread of invasive species. Accurate assessment of the invasive potential of an introduced species before introduction would provide a valuable tool to reduce invasions. This is particularly true in the USA, where a majority of invasive plants are introduced intentionally by the agriculture, forestry, and nursery trades (Reichard & White, 2001; Mack & Erneberg, 2002), and thus it may be possible to control introductions in the future. Treating the past introduc- tions of hundreds of woody exotic plants into New England as a ‘natural experiment’ in biogeography, we use statistical models to explore the ecology of woody plant invasions, test their predictive ability, and identify species that may pose future threats. The problems associated with invasive plants are conspicuous in the New England states where an estimated 877 non-native plant species have become established, comprising 31% of the flora (Rejmánek & Randall, 1994). Significant effort in the last 20 years has been spent on deter- mining the correlation between life-history traits and invasiveness (see Pysek & Richardson (2007) for a review). Correlates of invasive success recorded in the literature for plants include short juvenile period and interval between seed crops (Richardson & Rejmánek, 2004), high relative growth rate (Grotkopp et al., 1998; Pattison et al ., 1998; Grotkopp et al ., 2002), long flowering period (Goodwin et al., 1999; Cadotte & Lovett-Doust, 2001; Pysek et al., 2003; Lloret et al., 2005), vertebrate seed dispersal (Binggeli, 1996; Rejmánek & Richardson, 1996; Rejmánek, 1 Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, CT 06269-3043, USA, 2 Department of Biological Sciences, Plattsburgh State University of New York, 101 Broad Street, Plattsburgh, NY 12901, USA, 3 Lake Michigan Ecological Research Station, USGS Great Lakes Science Center, 1100 North Mineral Springs Road, Porter, IN 46304, USA *Correspondence: Patrick M. Herron, Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, CT 06269-3043, USA. Tel.: 011 (860) 486 5382; Fax: 011 (860) 486 6364; E-mail: patrickherron12@gmail.com Blackwell Publishing Ltd Invasive plants and their ecological strategies: prediction and explanation of woody plant invasion in New England Patrick M. Herron 1 *, Christopher T. Martine 2 , Andrew M. Latimer 1 and Stacey A. Leicht-Young 3