Effects of fire on riparian forests along a free-flowing dryland river

Juliet Stromberg, Tyler J. Rychener

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Riparian fire studies in the American Southwest have focused on flow-regulated rivers and typically show increase in introduced Tamarix, a species with high resprout capacity, and declines in Populus. Effects of fire, however, can vary with environmental setting. We examined riparian fire along the free-flowing Upper San Pedro River (Arizona) by making temporal comparisons supplemented by spatial contrasts between burned and unburned sites. Pre-fire, Populus fremontii and Salix gooddingii were dominant species, with Tamarix sparse in the understory. Species differed in mortality and resprout rates, producing post-fire vegetation change. Mortality was highest for Tamarix, intermediate for Salix, and lowest for Populus, and also varied among size classes. Resprout rate was low for Populus, high for Salix, and also high for the few surviving Tamarix. The net effect was changes in population size structure (relative shifts towards larger Populus but smaller individuals of other species) and forest composition (decreased abundance of Tamarix relative to Populus and Salix), and in spatial distribution of stems. Tamarix's low ability to survive fire resulted from competitive suppression by Populus and Salix, with their dominance a product of the site's flow regime. Results indicate that post-fire outcomes within the riparian Southwest are variable and context-dependent.

Original languageEnglish (US)
Pages (from-to)75-86
Number of pages12
JournalWetlands
Volume30
Issue number1
DOIs
StatePublished - Feb 1 2010

Keywords

  • Disturbance
  • Population structure
  • Populus
  • Salix
  • Semiarid
  • Tamarix

ASJC Scopus subject areas

  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

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