Ecosystems

, Volume 4, Issue 8, pp 797–806

Survival, Gap Formation, and Recovery Dynamics in Grassland Ecosystems Exposed to Heat Extremes: The Role of Species Richness

  • Liesbeth Van Peer
  • Ivan Nijs
  • Jan Bogaert
  • Iris Verelst
  • Dirk Reheul
Article

Abstract

A field experiment was performed in which the richness of perennial grasses (S) was varied in model ecosystems exposed to a simulated heat wave (free air temperature increase and drought). The proportion of individuals that survived the heat wave decreased with S, which could be ascribed to higher water consumption in the species-rich systems. Higher transpiration at high diversity was also observed in other studies using functional groups and could have originated from increased leaf area, less intense stomatal closure, or a combination of both. The increased tiller number per plant that we observed, while leaf area per tiller remained constant, suggests that an enhanced leaf area index was most likely responsible. However, competitive interactions also seemed to play a role in the influence of S on survival. Regrowth of the surviving individuals, expressed as leaf area per living plant after a recovery period following the heat wave, increased with S, most likely due to the dominance of productive species, which was facilitated by the additional space yielded by more intense gap formation at higher S (due to higher plant mortality). Species richness affected both the size and density of the gaps. Mean size increased exponentially with S, while density increased at low S but decreased at higher S when connectance of the gaps occurred. Size distribution of the gaps was not affected.

Key words: community stability; gap formation; heat wave; perennial grasses; regrowth; resistance; species richness. 

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Copyright information

© Springer-Verlag New York Inc. 2001

Authors and Affiliations

  • Liesbeth Van Peer
    • 1
  • Ivan Nijs
    • 1
  • Jan Bogaert
    • 1
  • Iris Verelst
    • 2
  • Dirk Reheul
    • 2
  1. 1.Research Group of Plant and Vegetation Ecology, Department of Biology, University of Antwerp, Universiteitsplein 1,, B-2610 Wilrijk, BelgiumBE
  2. 2.Department of Plant Production, Faculty of Agricultural and Applied Biological Sciences,, University of Ghent, Coupure Links 653, B-9000 Ghent, BelgiumBE

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