Get access

Rapid root extension during water pulses enhances establishment of shrub seedlings in the Atacama Desert

Authors

  • Mario F. León,

    1. Institute of Ecology and Biodiversity (IEB), Universidad de La Serena and Centre for Advanced Studies in Arid Zones (CEAZA), Casilla 599, La Serena, Chile.
    Search for more papers by this author
  • Francisco A. Squeo,

    1. Institute of Ecology and Biodiversity (IEB), Universidad de La Serena and Centre for Advanced Studies in Arid Zones (CEAZA), Casilla 599, La Serena, Chile.
    Search for more papers by this author
  • Julio R. Gutiérrez,

    1. Institute of Ecology and Biodiversity (IEB), Universidad de La Serena and Centre for Advanced Studies in Arid Zones (CEAZA), Casilla 599, La Serena, Chile.
    Search for more papers by this author
  • Milena Holmgren

    1. Resource Ecology Group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
    Search for more papers by this author

  • León, M.F. (mleon.36@gmail.com), Squeo, F.A. (f_squeo@userena.cl) & Gutiérrez, J.R. (jgutierr@userena.cl): Institute of Ecology and Biodiversity (IEB), Universidad de La Serena and Centre for Advanced Studies in Arid Zones (CEAZA), Casilla 599, La Serena, Chile.
    Holmgren, M. (corresponding author, Milena.Holmgren@wur.nl): Resource Ecology Group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.

  • Co-ordinating Editor: Beverly Collins.

Abstract

Questions: (1) What is the water threshold for shrub seedling establishment in arid scrubland? (2) How do seedling root growth morphological traits affect the water threshold required for seedling establishment?

Location: Arid scrubland, Atacama Desert, north-central Chile.

Methods: We conducted a field experiment with nine native shrub species under a gradient of simulated rainfall to test if species with deep root architecture have higher seedling survival rates and establish more successfully during water pulses.

Results: Seedling survival rate was very low; only 2% of the 12 150 planted seedlings survived the first summer drought. Seedling survival required at least 206 mm of water, which is twice the average rainfall and roughly equivalent to the precipitation during an ENSO (El Niño Southern Oscillation) event in this region. Seedling survival at the onset of the summer drought was best explained by leaf habit, root length and initial seedling size. However, only Senna cumingii seedlings survived through the first year. S. cumingii seedlings had distinctively longer roots than the other shrub species, enabling them to reach moister soil layers.

Conclusions: Water conditions resembling rainy years enhance shrub seedling establishment in the Atacama Desert, but the effects of higher water availability are strongly dependent on the shrub species. Rapid and deep rooting appears to be a very important functional trait for successful first-year survival in this arid system where water availability is highly episodic.

Ancillary