Seed dispersal of desert annuals

D. Lawrence Venable, Arturo Flores-Martinez, Helene C. Muller-Landau, Greg Barron-Gafford, Judith X. Becerra

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


We quantified seed dispersal in a guild of Sonoran Desert winter desert annuals at a protected natural field site in Tucson, Arizona, USA. Seed production was suppressed under shrub canopies, in the open areas between shrubs, or both by applying an herbicide prior to seed set in large, randomly assigned removal plots (10-30 m diameter). Seedlings were censused along transects crossing the reproductive suppression borders shortly after germination. Dispersal kernels were estimated for Pectocarya recurvata and Schismus barbatus from the change in seedling densities with distance from these borders via inverse modeling. Estimated dispersal distances were short, with most seeds traveling less than a meter. The adhesive seeds of P. recurvata went farther than the small S. barbatus seeds, which have no obvious dispersal adaptation. Seeds dispersed farther downslope than upslope and farther when dispersing into open areas than when dispersing into shrubs. Dispersal distances were short relative to the pattern of spatial heterogeneity created by the shrub and open space mosaic. This suggests that dispersal could contribute to local population buildup, possibly facilitating species coexistence. Overall, these results support the hypothesis that escape in time via delayed germination is likely to be more important for desert annuals than escape in space.

Original languageEnglish (US)
Pages (from-to)2218-2227
Number of pages10
Issue number8
StatePublished - Aug 2008


  • Desert annuals
  • Dispersal kernel
  • Escape in time and space
  • Inverse modeling
  • Pectocarya recurvata
  • Removal experiment
  • Schismus barbatus
  • Seed dispersal
  • Sonoran Desert
  • Species coexistence

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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