Landscape Ecology

, Volume 19, Issue 7, pp 761–771

Functional heterogeneity in resources within landscapes and herbivore population dynamics

  • Norman Owen-Smith
Research Article

Abstract

Large mammalian herbivores are notorious for their propensity towards population irruptions and crashes, yet many herbivore populations remain relatively stable. I explore how resource heterogeneity within landscapes dampens population instability, using a metaphysiological modelling approach considering patch state distributions. Resource heterogeneity is functionally stabilizing through spreading consumption away from preferred resources before these become critically depleted. Lower-quality resources act as a buffer against starvation during critical periods of the seasonal cycle. Enriching resource quality is destabilizing, even if patch diversity is maintained, because food quantity then becomes the limitation. The potential consequences of landscape fragmentation are explored using the Serengeti ecosystem, characterised by broadscale resource gradients, as a hypothetical example. Further insights provided by the model are illustrated with specific examples concerning the effects of patch scales and waterpoint distribution. A metaphysiological modelling approach enables the basic consequences of landscape heterogeneity to be distinguished from further effects that may arise from specific patch scales and configurations, without the distracting detail of spatially explicit models.

Key words

Fragmentation Large mammals Metaphysiological model Resource patches Serengeti Nationaal Park Tanzania ungulates Waterpoints 

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Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Norman Owen-Smith
    • 1
  1. 1.Centre for African Ecology, School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandSouth Africa

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