A long dispersal distance is widely used to indicate high invasiveness, but it ignores the temporal dimensions of plant invasion. Faster dispersal rates (= distance/time) of invasive species than non-invasive ones have been widely used in modeling species invasion and planning control management. However, the comparison of dispersal rate between invasive and non-invasive plants, particularly for dispersal on a local or landscape scale, has not been tested with a comprehensive dataset. Moreover, both effects of plant functional traits on the dispersal rate and variation in the functional-trait effects between invasive and non-invasive plants remain elusive. Compiling studies from 30 countries globally, we compared seed dispersal rates (km/year) on a local or landscape scale between 64 observations of invasive and 78 observations of non-invasive plants given effects of plant life forms, disturbance levels, and measurement methods. Furthermore, we compared the effects of functional traits on dispersal rate between invasive and non-invasive species. We found that: (1) Trait values were similar between the invasive and non-invasive plants except for the greater height of woody native plants than woody invasive ones; (2) Compared within the same plant life form, the faster dispersal rates of invasive species were found in herbaceous plants, not in woody plants, and disturbance level and measurement methods did not affect the rate comparison; (3) Plant height and seed length had significant effects on dispersal rates of both invasive and non-invasive plants, but the effect of leaf dry matter content (LDMC) was only significant on herbaceous invasive plants. The comparison of dispersal rate between invasive and non-invasive plants varied by plant life form. Between invasive and non-invasive species, their convergent trait values but divergent trait effects on dispersal suggest that the trait effects on invasiveness could be better understood by trait association with key factors in invasiveness, e.g., dispersal rate, than the direct comparison of trait values between invasive and non-invasive plants. 

We conducted searches for dispersal rates of invasive and non-invasive plants, independently. We compiled five functional traits that are relevant to dispersal rate from the Botanical Information and Ecology Network (BIEN) database (Maitner et al. 2018). The five traits are whole-plant height (m), leaf dry matter content (LDMC) (mg.g^-1), plant longevity (year), seed mass (mg), and seed length (mm).

We used a linear mixed-effect (LME) model with a phylogenetic relatedness between the species studied, and a phylogenetic tree of these species to compare dispersal rate and functional traits between invasive and non-invasive species. A structural equation model (SEM) was built to compare the direct and indirect effects of the five functional traits on the dispersal rate.