A positive feedback: Herbivory, plant growth, salinity, and the desertification of an arctic salt-marsh

- Authors: D. S. Srivastava, and R. L. Jefferies
  
  Date: 1996
  
  Journal: Journal of Ecology
  
  Volume: 84
  
  Number: 1
  
  Pages: 31-42
  
  Summary of Methods: This two year study suggests that a positive feedback process results in the destruction of salt-marsh swards and the exposure of bare sediments at La Perouse Bay, Manitoba, Canada. Results showed that soil salinity was inversely related to above-ground biomass and shoot density of Puccinellia phryganodes. Increased biomass led to reduced soil salinity and plant growth was reduced by high soil salinities, at sites where exclosures were erected. Leaf demography of transplanted experimental plants of Puccinellia differed in 1992, but not 1991, due to different amounts of above-ground biomass at the varying locations. Leaf births and deaths were highest for plants grown in sites where above-ground biomass was high and lowest for plants transplanted into bare sites. Grazing by lesser snow geese (Anser caerulescens caerulescens) had no effect on leaf demography in 1991, and only marginally increased the rate of leaf deaths in 1992. Algal crusts, which formed on bare or poorly vegetated sites, also reduced the growth of Puccinellia plants.
  
  Article Summary / Main Points: None
  
  Vegetation Types:
  
  MLRA Ecoregions:
  
  Agrovoc Control Words: Riparian zones Rangelands Wildlife
  Article Review Type: Refereed
  
  Article Type: Experimental Research
  
  Keywords: geese, graminoids, grazing, halophytes, hudson bay, shoot and leaf demography, standing crop
  
  Annotation: Grazing intensity is not specified.

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