A Network of Dynamic Keystone Species

摘要

A concept of dynamic keystone species is proposed based on simulation studies of replicator equations. We report that the variables of this equation can be categorized into three groups based on their individual dynamic behaviour. They are dominant, neutral and recessive phe-notypes. Because the growth rates are small in average, they are termed neutral phenotypes. Especially with a chaotic attractor, neutral phenotypes work as keystone species to control the stability of the system. The removal of neutral phenotypes may be a subtle perturbation, but it can have a large effect compared with its relative abundance, as it triggers an attractor switch. We also report that these neutral phenotypes form a "network that can provide combinatorial effects on the attractor switch. A mere topological structure of the interacting matrix is not sufficient for determining which may be a keystone species; instead, it is determined by the kind of the attractors they organize.