Competitive Networks: Nontransitive Competitive Relationships in Cryptic Coral Reef Environments

Abstract

Nonhierarchial sequences of interference competitive abilities, competitive networks, have been observed in Jamaican cryptic coral reef environments and also appear to exist in Jamaican open reef surface environments. These competitive networks are both numerous and complex; they appear more likely to be formed by interactions between than within major taxonomic groups. The exact spatial position an organism occupies and the rate at which organisms overgrow one another will be important determinants of patterns of species distribution on substrata supporting competitive networks. This will not be the case if a competitive hierarchy exists. The existence of a competitive network on a particular substratum will serve to increase the length of time required for single species resource monopolization relative to the time which would be required if a competitive hierarchy exists, assuming equivalent rates of overgrowth in both cases. The competitive networks situation provides a mechanism for the development of specific types of coevolutionary relationships.