Refining the stress‐gradient hypothesis for competition and facilitation in plant communities

Summary The stress‐gradient hypothesis (SGH) predicts that the frequency of facilitative and competitive interactions will vary inversely across abiotic stress gradients, with facilitation being more common in conditions of high abiotic stress relative to more benign abiotic conditions. With notable exceptions, most tests of the SGH have studied the interaction between a single pair or a few pairs of species, and thus have evaluated shifts in the magnitude and direction of pair‐wise interactions along stress gradients, rather than shifts in the general frequency of interactions. The SGH has been supported by numerous studies in many ecosystems, has provided a crucial foundation for studying the interplay…

• NS
  National Science Foundation
• UD
  U.S. Department of Agriculture
• AW
  Andrew W. Mellon Foundation
• FB
  Fundación BBVA

  Award: BIOCON06/105
• UO
  University of Montana
• CD
  Comunidad de Madrid

  Award: S-0505/AMB/0335
• ES
  Ecological Society of America
• BE
  British Ecological Society

  Awards: 231/1975, Studentship 231/1975
• MD
  Ministerio de Ciencia e Innovación

  Award: S-0505/AMB/0335
• BB
  Banco Bilbao Vizcaya Argentaria
• NS
  Natural Sciences and Engineering Research Council of Canada
• RM
  Rocky Mountain Research Station
• ES
  European Social Fund