Biological soil crusts modulate nitrogen availability in semi-arid ecosystems: Insights from a Mediterranean grassland

Andrea P. Castillo-Monroy, Fernando T. Maestre, Manuel Delgado-Baquerizo, Antonio Gallardo

Research output: Contribution to journalArticlepeer-review

138 Scopus citations


Biological soil crusts (BSCs) greatly influence the N cycle of semi-arid ecosystems, as some organisms forming them are able to fix atmospheric N. However, BSCs are not always taken into account when studying biotic controls on N cycling and transformations. Our main objective was to understand how BSCs modulate the availability of N in a semi-arid Mediterranean ecosystem dominated by the tussock grass Stipa tenacissima. We selected the six most frequent soil cover types in the study area: S. tenacissima tussocks (ST), Retama sphaerocarpa shrubs (RS), and open areas with very low (BS), low (LC) medium (MC) and high (HC) cover of well developed and lichen-dominated BSCs. The temporal dynamics of available N dynamics followed changes in soil moisture. Available NH4+-N did not differ between microsites, while available NO3--N was substantially higher in the RS than in any other microsite. No significant differences in the amount of available NO3--N were found between ST and BS microsites, but these microsites had more NO3--N than those dominated by BSCs (LC, MC and HC). Our results suggest that BSCs may be inhibiting nitrification, and highlight the importance of this biotic community as a modulator of the availability of N in semi-arid ecosystems.

Original languageEnglish (US)
Pages (from-to)21-34
Number of pages14
Issue number1
StatePublished - 2010


  • Biological soil crusts
  • Nitrification potential
  • Nitrogen availability
  • Nitrogen cycle
  • Semi-arid ecosystem
  • Stipa tenacissima

ASJC Scopus subject areas

  • Soil Science
  • Plant Science


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