The pervasive and multifaceted influence of biocrusts on water in the world's drylands

David J. Eldridge*, Sasha Reed, Samantha K. Travers, Matthew A. Bowker, Fernando T. Maestre, Jingyi Ding, Caroline Havrilla, Emilio Rodriguez-Caballero, Nichole Barger, Bettina Weber, Anita Antoninka, Jayne Belnap, Bala Chaudhary, Akasha Faist, Scott Ferrenberg, Elisabeth Huber-Sannwald, Oumarou Malam Issa, Yunge Zhao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

137 Scopus citations


The capture and use of water are critically important in drylands, which collectively constitute Earth's largest biome. Drylands will likely experience lower and more unreliable rainfall as climatic conditions change over the next century. Dryland soils support a rich community of microphytic organisms (biocrusts), which are critically important because they regulate the delivery and retention of water. Yet despite their hydrological significance, a global synthesis of their effects on hydrology is lacking. We synthesized 2,997 observations from 109 publications to explore how biocrusts affected five hydrological processes (times to ponding and runoff, early [sorptivity] and final [infiltration] stages of water flow into soil, and the rate or volume of runoff) and two hydrological outcomes (moisture storage, sediment production). We found that increasing biocrust cover reduced the time for water to pond on the surface (−40%) and commence runoff (−33%), and reduced infiltration (−34%) and sediment production (−68%). Greater biocrust cover had no significant effect on sorptivity or runoff rate/amount, but increased moisture storage (+14%). Infiltration declined most (−56%) at fine scales, and moisture storage was greatest (+36%) at large scales. Effects of biocrust type (cyanobacteria, lichen, moss, mixed), soil texture (sand, loam, clay), and climatic zone (arid, semiarid, dry subhumid) were nuanced. Our synthesis provides novel insights into the magnitude, processes, and contexts of biocrust effects in drylands. This information is critical to improve our capacity to manage dwindling dryland water supplies as Earth becomes hotter and drier.

Original languageEnglish (US)
Pages (from-to)6003-6014
Number of pages12
JournalGlobal change biology
Issue number10
StatePublished - Oct 1 2020


  • biological soil crust
  • bryophyte
  • cryptogam
  • cyanobacteria
  • hydrological cycle
  • infiltration
  • lichen
  • sediment production
  • soil hydrology
  • soil moisture

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • General Environmental Science


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