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A Nonequilibrium Marine Predator‐Prey Interaction
Author(s) -
Katz Clifford H.
Publication year - 1985
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1938005
Subject(s) - barnacle , intraspecific competition , biology , predation , predator , ecology , competition (biology) , rocky shore , intertidal zone , functional response , population , crustacean , demography , sociology
The assumptions and predictions of equilibrium predator—prey theory were tested in a southern New England intertidal community. Responses of the predatory snail Urosalpinx cinerea and the prey population dynamics of the barnacle Balanus balanoides were examined with field experiments and observations. The functional response, developmental responses, intraspecific competition, and species preference response of U. cinerea were destabilizing. Instantaneous and exploitative models revealed the functional response of U. cinerea to be a type II response. Increases in the size of U. cinerea did not affect the feeding rate per individual predator or the type of functional response. Experimental analysis of competition among U. cinerea and estimates of predator densities in the field indicated that intraspecific interactions do not cause a significant reduction in the consumption of barnacles. Presented with several frequencies of B. balanoides and the mussel Mytilus edulis, the predator showed a distinct preference for barnacles. As a result of predation, substrate cover of B. balanoides on the lower shore was transient and local extinction occurred within the years between 1977 and 1980. The evidence of destablizing predator response and prey extinction strongly suggest that the interaction between U. cinerea and B. balanoides is best explained by nonequilibrium theory.