Some complications of the elementary forms of competition in a source/sink and metacommunity context: the role of intranstive loops

Dynamic interspecific interactions are thought to contribute to fundamental structures of ecological communities. Using the Yodzis framework of dominance control versus founder control versus niche control, the importance of intransitive loops in sub-communities in a source/sink or metacommunity competition context is examined. It is found that a three-species sub-community sampled from a species pool composed of nothing but dominance controlled species pairs can result in a stable three species coexistence. It is shown that if effect and response competition are balanced, the overall sub-community will be persistent, anchored by one or more intransitive loops. It is proposed that such an arrangement be referred to as an intransitive structure. It is concluded that persistence of a sub-community (when species pairs in the species pool are all dominance controlled) of more than three species is possible only if it has an intransitive structure.