Plant Ecology

, Volume 130, Issue 2, pp 155–161

Competitive interactions between palatable and unpalatable grasses native to a temperate semi-arid grassland of Argentina

  • A. S. Moretto
  • R. A. Distel
Article

DOI: 10.1023/A:1009723009012

Cite this article as:
Moretto, A.S. & Distel, R.A. Plant Ecology (1997) 130: 155. doi:10.1023/A:1009723009012

Abstract

The argument that selective grazing leads to competitive replacement of palatable grasses by unpalatable grasses is based upon the assumption that the competitive ability of the palatable species is higher than the one of unpalatable species in the absence of grazing. In order to test this hypothesis we have compared the competitive ability of Stipa clarazii (palatable) and S. trichotoma (unpalatable) under field conditions, and S. clarazii and S. gynerioides (unpalatable) under greenhouse conditions. The three species are native to a temperate semi-arid grassland of central Argentina. In the field experiment, plants of both species were grown either independently or in pairs (palatable + unpalatable), protected from grazing. Shoot and seed production were measured at the end of the growing seasons of 1993, 1994 and 1995. In the greenhouse experiment, plants of both species were grown in pots, either in monoculture or in mixture, under conditions of high and low water and mineral nutrient availability. Total biomass and seed production were measured at the end of the experimental period. In both experiments the presence of the unpalatable species did not affect (P < 0.05) the productive responses of the palatable species. On the contrary, the presence of the palatable species significantly reduced (P < 0.05) the productive responses of the unpalatable species. Our results support the assumption, on which most interpretations of floristic changes induced by grazing are based, that the competitive ability of palatable grasses is higher than the one of unpalatable grasses in the absence of grazing.

Competitive ability Grass competition Grassland ecology Native Grasslands Palatable/unpalatable grasses 

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • A. S. Moretto
    • 1
  • R. A. Distel
    • 1
  1. 1.Departamento de Agronomía, Cerzos/ConicetUniversidad Nacional del SurBahía BlancaArgentina

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