title: Cryptic spatial aggregation of the cushion plant Azorella selago (Apiaceae) revealed by a multilocus molecular approach suggests frequent intraspecific facilitation under sub-Antarctic conditions.
abstract: OBJECTIVE
  In abiotically severe habitats, intraspecific aggregations can increase species' fitness by ameliorating stressful environmental factors. However, the difficulty of identifying individual plants in some growth forms makes the measurements of intraspecific aggregation, and therefore the assessment of intraspecific facilitation, problematic. In this study, we examined the genotype composition within cushions of Azorella selago, a sub-Antarctic cushion plant, to investigate the potential extent of intraspecific facilitation.
  
  
  METHODS
  The study was performed on Marion Island, South Africa. Two to eight samples were collected from 42 A. selago cushions, comprising eight different growth forms. Samples were genotyped using seven microsatellite markers.
  
  
  RESULTS
  We showed that all cushion shapes, with the exception of small cushions, may be comprised of more than one genetically distinct individual.
  
  
  CONCLUSIONS
  Under harsh sub-Antarctic conditions, intraspecific aggregation between A. selago individuals appears common and may be driven by the positive impacts of environmental amelioration.
authors: Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
authors: Mia E
authors: ME
authors: Cerfonteyn
authors: Peter C
authors: PC
authors: Le Roux
authors: Bettine Jansen
authors: BJ
authors: Van Vuuren
authors: Céline
authors: C
authors: Born