Environmental factors affecting dispersal, germination and distribution of Stipa capensis in the Negev Desert, Israel

Bertrand Boeken, Clara Ariza, Yitzchak Gutterman, Eli Zaady

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

The effects of postmaturation ambient temperatures, light, as well as chemical and structural properties of the substrate on germination and patch distribution of Stipa capensis in a shrubland landscape were studied. This species is a dominant annual grass in exposed intershrub areas covered with biological loess soil crusts in the northern Negev Desert. Freshly matured caryopses do not germinate. After 7-8 months of dry storage at high temperatures, there was a significant reduction in primary dormancy and an increase in the rate and percentage of germination of caryopses stored at high temperatures. The speed and percentages of germination were lower on various sterile substrates, such as organic matter and loose loess soil, in comparison with similar live substrates or the control on filter paper. In 3 of 4 years of field observations in semi-arid shrubland, the density of Stipa capensis plants on soil crust in the exposed intershrub areas was significantly higher than below shrubs. The positive effects of higher temperatures on the dry soil during summer, before the season with rains, and of light during germination, can favor germination in exposed patches. Although germination responses to storage temperature and light regime differentiate between patch types before and during germination, other processes may be critical for the pattern of distribution of Stipa capensis. These include dispersal of caryopses, arrival, soil penetration and density of local seed banks, as well as substrate properties affecting germination and plant density, in different landscape patches.

Original languageEnglish
Pages (from-to)533-540
Number of pages8
JournalEcological Research
Volume19
Issue number5
DOIs
StatePublished - 1 Sep 2004

Keywords

  • Biological soil crust
  • Desert annual grass
  • Dry storage temperatures
  • Primary dormancy
  • Soil seed bank

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