Taxonomic identity determines N2 fixation by canopy trees across lowland tropical forests

Nina Wurzburger, Lars O. Hedin

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Legumes capable of fixing atmospheric N2 are abundant and diverse in many tropical forests, but the factors determining ecological patterns in fixation are unresolved. A long-standing idea is that fixation depends on soil nutrients (N, P or Mo), but recent evidence shows that fixation may also differ among N2-fixing species. We sampled canopy-height trees across five species and one species group of N2-fixers along a landscape P gradient, and manipulated P and Mo to seedlings in a shadehouse. Our results identify taxonomy as the major determinant of fixation, with P (and possibly Mo) only influencing fixation following tree-fall disturbances. While 44% of trees did not fix N2, other trees fixed at high rates, with two species functioning as superfixers across the landscape. Our results raise the possibility that fixation is determined by biodiversity, evolutionary history and species-specific traits (tree growth rate, canopy stature and response to disturbance) in the tropical biome.

Original languageEnglish (US)
Pages (from-to)62-70
Number of pages9
JournalEcology letters
Issue number1
StatePublished - Jan 1 2016

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics


  • Arbuscular mycorrhizal fungi
  • Biodiversity
  • Disturbance
  • Molybdenum
  • Nitrogen
  • Nutrient limitation
  • Phosphorus
  • Tree-fall gaps


Dive into the research topics of 'Taxonomic identity determines N2 fixation by canopy trees across lowland tropical forests'. Together they form a unique fingerprint.

Cite this