Soil fungal abundance and plant functional traits drive fertile island formation in global drylands

Authors Organisations
  • Raúl Ochoa-Hueso(Author)
    Autonomous University of Madrid
  • David J. Eldridge(Author)
    University of New South Wales
  • Manuel Delgado-Baquerizo(Author)
    University of Colorado
    King Juan Carlos University
  • Santiago Soliveres(Author)
    University of Bern
  • Matthew A. Bowker(Author)
    Northern Arizona University
  • Nicolas Gross(Author)
    King Juan Carlos University
    National Institute of Agricultural Research
    Université La Rochelle
  • Yoann Le Bagousse-Pinguet(Author)
    King Juan Carlos University
  • José L. Quero(Author)
    University of Cordoba
  • Miguel García-Gómez(Author)
    King Juan Carlos University
  • Enrique Valencia(Author)
    King Juan Carlos University
  • Tulio Arredondo(Author)
    Instituto Potosino de Investigación Científica y Tecnológica
  • Laura Beinticinco(Author)
    CONICET - Universidad Nacional de La Pampa
  • Donaldo Bran(Author)
    Instituto Nacional de Tecnologia Agropecuaria
  • Alexa Cea(Author)
    Universidad de La Serena
  • Daniel Coaguila(Author)
    Universidad Nacional San Agustín de Arequipa
  • Andrew J. Dougill(Author)
    University of Leeds
  • Carlos I. Espinosa(Author)
    Universidad Técnica Particular de Loja
  • Juan Gaitán(Author)
    Instituto De Suelos
  • Reginald T. Guuroh(Author)
    University of Cologne
    University of Bonn
  • Elizabeth Gusman(Author)
    Universidad Técnica Particular de Loja
  • Julio R. Gutiérrez(Author)
    Universidad de La Serena
  • Rosa M. Hernández(Author)
    Universidad Experimental Simón Rodríguez
  • Elisabeth Huber-Sannwald(Author)
    Instituto Potosino de Investigación Científica y Tecnológica
  • Thomas Jeffries(Author)
    Western Sydney University
  • Anja Linstädter(Author)
    University of Cologne
  • Rebecca. L. Mau(Author)
    Northern Arizona University
  • Jorge Monerris(Author)
    Université du Québec à Montréal
  • Aníbal Prina(Author)
    CONICET - Universidad Nacional de La Pampa
  • Eduardo Pucheta(Author)
    Universidad Nacional de San Juan
  • Ilan Stavi(Author)
    Dead Sea and Arava Science Center
  • Andrew Thomas(Author)
  • Eli Zaddy(Author)
    Gilat Research Center
  • Brajesh K. Singh(Author)
    Western Sydney University
  • Fernando T. Maestre(Author)
    King Juan Carlos University
Type Article
Original languageEnglish
Pages (from-to)242-253
Number of pages12
JournalJournal of Ecology
Issue number1
Early online date25 Oct 2017
Publication statusPublished - 31 Jan 2018
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Dryland vegetation is characterized by discrete plant patches that accumulate and capture soil resources under their canopies. These “fertile islands” are major drivers of dryland ecosystem structure and functioning, yet we lack an integrated understanding of the factors controlling their magnitude and variability at the global scale.

We conducted a standardized field survey across 236 drylands from five continents. At each site, we measured the composition, diversity and cover of perennial plants. Fertile island effects were estimated at each site by comparing composite soil samples obtained under the canopy of the dominant plants and in open areas devoid of perennial vegetation. For each sample, we measured 15 soil variables (functions) associated with carbon, nitrogen and phosphorus cycling and used the relative interaction index to quantify the magnitude of the fertile island effect for each function. In 80 sites, we also measured fungal and bacterial abundance (quantitative PCR) and diversity (Illumina MiSeq).

The most fertile islands, i.e. those where a higher number of functions were simultaneously enhanced, were found at lower elevation sites with greater soil pH values and sand content under semiarid climates, particularly at locations where the presence of tall woody species with a low-specific leaf area increased fungal abundance beneath plant canopies, the main direct biotic controller of the fertile island effect in the drylands studied. Positive effects of fungal abundance were particularly associated with greater nutrient contents and microbial activity (soil extracellular enzymes) under plant canopies.

Synthesis. Our results show that the formation of fertile islands in global drylands largely depends on: (1) local climatic, topographic and edaphic characteristics, (2) the structure and traits of local plant communities and (3) soil microbial communities. Our study also has broad implications for the management and restoration of dryland ecosystems worldwide, where woody plants are commonly used as nurse plants to enhance the establishment and survival of beneficiary species. Finally, our results suggest that forecasted increases in aridity may enhance the formation of fertile islands in drylands worldwide.


  • aridity, drylands, fertile islands, fungal abundance, multiple threshold approach, plant functional traits, relative interaction index, soil properties