Tutorial Modelling of Geosphere-Biosphere Interactions: The Effect of Percolation-Type Habitat Fragmentation

W. von Bloh, A. Block, M. Parade and H.J. Schellnhuber

Potsdam Institute for Climate Impact Research (PIK)
Telegrafenberg, P.O. Box 601203, D-14412 Potsdam
Germany

Physica A 226, 186-196 (1999)

Abstract:

A considerably extended two-dimensional version of the famous Lovelock-Watson model for geosphere-biosphere interactions (``Daisyworld'') is employed to investigate the impact of habitat fragmentation. The latter is dynamically modelled through the standard percolation process first introduced by solid state theory. It is found that the connectivity of the space accessible for life is crucial for ecological performance. In particular, the self stabilizing capacity of the biosphere strongly depends on the fragmentation topology. An extremely rich and partially counter-intuitive eco-dynamics is observed when a simple community structure, consisting of plants and herbivores, is introduced. Quite remarkably, high herbivore vitality destroys the stability of the entire biosphere in a way reminiscent of ``desertification''.

 
• Introduction
• Modelling the geosphere-biosphere feedback interactions
  • The Lovelock-Watson model of ``Daisyworld''
  • Introducing spatial dependence, competition, and mutation into Daisyworld
  • Introducing herbivores into Daisyworld
• The impacts of fragmentation on ecologic performance
  • Self-stabilization of global temperature without herbivores
  • The role of herbivores in a fragmented landscape
• Summary and outlook
• References
• About this document ...