Correlations between global and regional measures of invasiveness vary with region size

By

Dawson, Wayne
Keser, Lidewij
Winter, Marten
Pyšek, Petr
Kartesz, John T
Nishino, Misako
Fuentes Parada, Nicol E.
Chytrý, Milan
Celesti-Grapow, Laura
Kleunen, Mark van, 1973-

Type

Article

Date of Publication

2013

Original Publication

NeoBiota : advancing research on alien species and biological invasions

Volume

16

Pages

59-80

Subjects

abundance , alien species distribution , database , exotic plant , global invasiveness , range size

Contributed by

Pensoft Publishers

Language

English

Published by

Sophia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/neobiota.16.4351

 

Abstract

We aimed to assess the utility of the Global Compendium of Weeds (GCW) as an indicator of plant invasiveness, by relating it to invasiveness at smaller scales. We correlated two global measures of invasiveness for alien plant species taken from the GCW (the total number of references for each species and the number of continental areas they are reported from), against distribution data from 18 regions (countries and continents). To investigate relationships between correlation strength and region size and spatial resolution (size of distribution units), we conducted meta-analyses. Finally, invasiveness measures were correlated against the number of habitats occupied by alien plant species and their median abundance in those habitats, in fine-scale vegetation plots in the Czech Republic and the state of Montana (USA). The majority of Spearman’s rho coefficients between GCW-derived invasiveness and regional distributions were less than 0.4. Correlation strength was positively related to region size and resolution. Correlations were weaker when the number of habitats occupied by a species, and species abundances within occupied habitats, were considered. We suggest that the use of the GCW as an invasiveness measure is most appropriate for hypotheses posed at coarse, large scales. An exhaustive synthesis of existing regional distributions should provide a more accurate index of the global invasiveness of species.