Extinction dynamics in Lotka-Volterra ecosystems on evolving networks
F. Coppex1 , M. Droz1 , A. Lipowski1,2
1 Department of Physics, University of Geneva, CH 1211 Geneva 4, Switzerland
2 Faculty of Physics, A. Mickiewicz University, 61-614 Poznań, Poland
Phys. Rev. E , 69, 061901 (2005)
We study a model of a multi-species ecosystem described by Lotka-Volterra-like equations. Interactions among species form a network whose evolution is determined by the dynamics of the model. Numerical simulations show power-law distribution of intervals between extinctions, but only for ecosystems with sufficient variability of species and with networks of connectivity above certain threshold that is very close to the percolation threshold of the network. Effect of slow environmental changes on extinction dynamics, degree distribution of the network of interspecies interactions, and some emergent properties of our model are also examined.