Oecologia

, Volume 88, Issue 2, pp 173–180

Responses to simulated herbivory and water stress in two tropical C4 grasses

Authors

  • Milton Simoes
    • Dpto. Estudios AmbientalesUniversidad Simón Bolívar
  • Zdravko Baruch
    • Dpto. Estudios AmbientalesUniversidad Simón Bolívar
Original Papers

DOI: 10.1007/BF00320808

Cite this article as:
Simoes, M. & Baruch, Z. Oecologia (1991) 88: 173. doi:10.1007/BF00320808

Summary

The African grass Hyparrhenia rufa has established itself successfully in South American savannas (Llanos) and displaced dominant native grasses such as Trachypogon plumosus from the wetter and more fertile habitats. Several ecophysiological traits have been related to the higher competitive capacity of H. rufa. To further analyze the behavior of both species, their growth, biomass allocation, physiological and architectural responses to defoliation and water stress were compared under controlled conditions. Although total, aerial and underground biomass decreased under defoliation in both grasses, increases in clipped-leaf biomass and area compensated for defoliation in H. rufa but not in T. plumosus. This difference was due mainly to a higher proportion of assimilates being directed to leaf and tiller production and a higher leaf growth rate in the African grass as compared to T. plumosus, which showed incrased senescence under frequent defoliation. In both species, water stress ameliorated the effects of defoliation. The ability to compensate for defoliated biomass in H. rufa is possibly related to its long coevolution with large herbivores in its original African habitat and is apparently one of the causes of its success in Neotropical savannas.

Key words

C4 grassesHerbivoryHyparrhania rufaSavannasTrachypogon plumosusWater stress

Copyright information

© Springer-Verlag 1991