Effects of pest control on a food chain in patchy environment: Species-dependent activity range on multilayer graphs

摘要

Ecosystems on earth are strongly affected by human life. We pay attention to pest control in a patchy environment. To date, many authors have reported the indeterminacy in pest control. Most of these works have been studied in single-habitat systems. In the present article, however, we consider a food chain model (prey, predator and top predator) on five networks of patches, where node and link denote habitable patch and migration path, respectively. Each network includes three layers which represent the activity ranges of respective species. Reaction-migration equations are solved analytically and numerically. It is found the dynamics largely change depending on the geometry of networks. When removal rate of top predator is increased, the so-called "top-down effect" is commonly observed. In this case, the pest control will be successful, but extinction point of top predator largely differs on different networks. When removal rate of intermediate predator is increased, the responses of system become complicated. The responses differ not only for each patch but also for each geometry. Hence, the pest control on intermediate predators may fail.