Bond and site percolation and habitat destruction in model ecosystems

Habitat destruction is one of the primary causes of species extinction. In the present article, we apply bond and site destructions to a prey-predator system. Predator reproduction is disturbed by these destructions, while prey sustains no direct damage. It is found for both bond and site destructions that the number of predators increases in spite of the increase in destruction. However, if the destruction is too great, the predators decreases and eventually goes extinct. The mean-field theories for both type of destruction predict the same extinction threshold values. In contrast, the simulations for bond and site destructions reveal that extinction thresholds are much smaller than the mean-field theory predicts. This may be the result of the fragmentation of habitat via the percolation of habitat destruction.