Are introduced species better dispersers than native species? A global comparative study of seed dispersal distance

PLoS One. 2013 Jun 20;8(6):e68541. doi: 10.1371/journal.pone.0068541. Print 2013.

Abstract

We provide the first global test of the idea that introduced species have greater seed dispersal distances than do native species, using data for 51 introduced and 360 native species from the global literature. Counter to our expectations, there was no significant difference in mean or maximum dispersal distance between introduced and native species. Next, we asked whether differences in dispersal distance might have been obscured by differences in seed mass, plant height and dispersal syndrome, all traits that affect dispersal distance and which can differ between native and introduced species. When we included all three variables in the model, there was no clear difference in dispersal distance between introduced and native species. These results remained consistent when we performed analyses including a random effect for site. Analyses also showed that the lack of a significant difference in dispersal distance was not due to differences in biome, taxonomic composition, growth form, nitrogen fixation, our inclusion of non-invasive introduced species, or our exclusion of species with human-assisted dispersal. Thus, if introduced species do have higher spread rates, it seems likely that these are driven by differences in post-dispersal processes such as germination, seedling survival, and survival to reproduction.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ecosystem
  • Germination / physiology
  • Introduced Species*
  • Magnoliopsida / classification
  • Magnoliopsida / growth & development
  • Magnoliopsida / physiology
  • Models, Biological
  • Population Dynamics
  • Seed Dispersal / physiology*
  • Seedlings / growth & development
  • Seedlings / physiology*
  • Seeds / growth & development
  • Seeds / physiology*

Grants and funding

H.F.M. was supported by a scholarship from the Evolution & Ecology Research Centre at UNSW. A.T.M. was supported by funding from the Australian Research Council (DP 0984222). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.