DOI: 10.5061/dryad.kwh70rz5g
title: Introduction history mediates naturalization and invasiveness of cultivated plants

description: Aim: Species characteristics and cultivation are both associated with
 alien plant naturalization and invasiveness. Particular species
 characteristics are favored for cultivation, obscuring the relationship
 between traits and naturalization success. We sought to better understand
 the drivers of naturalization and invasiveness by analyzing relationships
 with species characteristics and cultivation and by disentangling the
 direct effects of characteristics from the indirect effects mediated by
 cultivation. Location: Great Britain Time period: c. 1000–present Major
 taxa studied: Seed plants Methods: We used a comprehensive dataset of
 17,396 alien plant taxa introduced to Great Britain before 1850, a country
 with one of the most well-documented histories of plant introductions. We
 integrated this with cultivation data from historical and modern records
 of botanic gardens and commercial nurseries and with trait data.
 Accounting for time since introduction, we quantified the influences of
 cultivation and species characteristics on present-day naturalization and
 invasiveness in Great Britain. Results: Larger native range size, earlier
 flowering, long-lived herbaceous growth form, and outdoor cultivated
 habitat were all associated with naturalization. However, these
 relationships between characteristics and naturalization largely reflected
 cultivation patterns. The indirect, mediating influence of cultivation on
 naturalization varied among species characteristics, and was relatively
 strong for growth form and weak for native range size. Cultivation
 variables, particularly availability in present-day nurseries, best
 explained invasiveness, while species characteristics had weaker
 associations. Main conclusions: Human influence on species introduction
 and cultivation is associated with increased probability of naturalization
 and invasiveness, and it has measurable indirect effects by biasing the
 distribution of species characteristics in the pool of introduced species.
 Accounting for human cultivation preferences is necessary to make
 ecological interpretations of the effects of species characteristics on
 invasion.
description: The main dataset used in this manuscript is provided as a CSV
 file (CultivationGB_Dataset.csv). Each row describes a seed plant taxon
 introduced to Great Britain that was listed in J.C. Loudon's (1850)
 <em>Hortus Britannicus.</em> Associated data describing the
 introduction year, species characteristics, and cutivation variables are
 also provided for each taxon. The sources used to compile this dataset are
 lengthy and the methods complex, and all has been described in detail in
 the main manuscript and the accompanying Supporting Information. All
 columns in the main dataset are described in the README file. The R code
 files used for analysis are provided in a ZIP file
 (CultivationGB_Analysis.zip), and each R file is described in detail in
 the README file. Last, the phylogenetic tree of the taxa in this study is
 included as a TRE file (CultivationGB_Phylogeny.tre). 
 Loudon, J. C. (1850).
 <em>Hortus Britannicus: A Catalogue of All the Plants Indigenous,
 Cultivated in, or Introduced to Britain</em> (J. W. Loudon, Ed.; 4th
 ed.). Longman, Brown, Green, and Longmans.
description: <strong>Dataset of taxa introduced to Great Britain before
 1850 (CultivationGB_Dataset.csv): </strong>this is the main dataset
 that can be used to run the analyses described in the manuscript. The
 columns in the dataset are listed and described in the README
 file. <strong>R code used to conduct analyses
 (CultivationGB_Analysis.zip): </strong>this ZIP file includes the R
 code files used to run the analyses in this manuscript. The files are
 listed and described in depth in the README file.
 <strong>Phylogenetic tree of the taxa in the dataset
 (CultivationGB_Phylogeny.tre)</strong>