Effect of Spatial Arrangement of Habitat Patches on Local Population Size

The purpose of this study was to examine the effect of the spatial arrangement of host—plant patches on local abundance of the cabbage butterfly (Piers rapae). By considering the movement behavior of adult females, we developed a detailed simulation model of P. rapae in patchy habitats. The model was then used to predict effects of cabbage patch spatial arrangement on P. rapae egg densities for a specific spatial arrangement of cabbage patches. Field studies confirmed the predictions. The results of this study are discussed in the context of the effects of dispersal behavior on relationships between aptch spatial arrangement and local abundance. The findings are consistent with general simulation results of L. Fahrig and J. E. Paloheimo (personal observation) that suggest large dispersal distances decrease the effect of the spatial arrangement of habitat patches on local population size.