Study of the temporal stability of spatial structures by analysing series of totally paired faunistic tables

In this paper, we investigate the potential of partial triadic analysis (PTA), already introduced in ecology by THIOULOUSE and CHESSEL (1987). The principle of the method is presented in a simplified way to facilitate its use by ecologists. This method allows the simultaneous principal components analyses (PCA) of several species composition tables corresponding to the collection of organisms in various locations at different occasions to be coordinated. In this case, PTA permits to find a spatial structure common to every table (i.e., sampling occasion) and to study its temporal stability Therefore, PTA starts by searching an average table called compromise Then, the compromise table is analysed and its reproductibility by each initial table is finally investigated. Using the same sampling design, we also present the analysis of a series of contingency tables (FOUCART, 1978) which represents a different approach since it considers the frequency distribution of species rather than their abundance. We illustrate these two K-set methods by an example in stream ecology We demonstrate the power of these methods for depicting the temporal evolution of the spatial structures.