Stability of Species and of Community for the Benthos of two Lagoons

Abstract

Bethnic communities (predominantly bivalve mollusks) of two southern California lagoons (Mugu Lagoon and Tijuana Slough) were sampled intensively once every 4 mo over a 37—mo period. The two lagoons differed significantly in species diversity. The lagoon with the lowest species diversity, Mugu Lagoon, was composed of species whose populations generally exhibited much greater temporal variability (showing lower stability of component species); however, the proportionate community composition of each lagoon varied to an equal degree through time (demonstrating equivalence in stability of community composition). This nearly paradoxical result can be explained in part by a higher level of synchrony in the temporal fluctuations of the species populations at Mugu Lagoon. A similar response by several species at Mugu Lagoon to an environmental perturbation, dilution after a heavy rain, contributed to this higher level of synchrony.