This study examines whether meso-scale meteorological events, in particular the alternation of cold and mild periods, influenced the structure of four Abi cr alba communities, sampled from 1977 to 1992 on the northwest French coast. We propose a new numerical procedure to describe temporal variations in the structure of each assemblage, using some niche-oriented models recently developed by Tokeshi (1993). The description of the temporal changes in the structure of each community was summarized into a 2D-plot of an ordination, performed on observed and simulated patterns. Results showed that important changes occurred in these four assemblages, which were not directly related to the meso-scale climatic events, but mainly to the local environmental factors and biotic interactions. Furthermore, it appears that stable environmental conditions would favour more stable structures, but do not determine the precise type of the structure.