This paper examines how to obtain species biplots in unconstrained or constrained ordination without resorting to the Euclidean distance [used in principal-component analysis (PCA) and redundancy analysis (RDA)] or the chi-square distance [preserved in correspondence analysis (CA) and canonical correspondence analysis (CCA)] which are not always appropriate for the analysis of community composition data. To achieve this goal, transformations are proposed for species data tables. They allow ecologists to use ordination methods such as PCA and RDA, which are Euclidean-based, for the analysis of community data, while circumventing the problems associated with the Euclidean distance, and avoiding CA and CCA which present problems of their own in some cases. This allows the use of the original (transformed) species data in RDA carried out to test for relationships with explanatory variables (i.e. environmental variables, or factors of a multifactorial analysis-of-variance model); ecologists can then draw biplots displaying the relationships of the species to the explanatory variables. Another application allows the use of species data in other methods of multivariate data analysis which optimize a least-squares loss function; an example is K-means partitioning.

Controlled field experiments were used to test the effects of surface—deposit feeders on succession at the Skagit flats, an intertidal sandflat in northern Puget Sound. The tube builders Hobsonia florida (Polychaeta, Ampharetidae), Pseudopolydora kempi japonica (Polychaeta, Spionidae), and Lanais sp. (Crustacea, Peracarida) facilitate the recruitment of other taxa on 10—cm2 azoic patches. Simulated animal tubes facilitated the immigration of Tanais sp. and oligochaetes. Macoma balthica, a tellinid bivalve, facilitated the immigration of H. florida, while inhibiting that of Tanais sp. These experiments clearly documented that facilitation rather than inhibition is the dominant process governing succession in the skatole community. The facilitation model of succession offers a viable alternate explanation for many soft—bottom benthic processes previously explained by the inhibition model.

The benthic infaunal mudflat community of Boston Harbor’s Savin Hill Cove was sampled every other week from January though December 1986. Eighty replicate samples per date allowed precise estimates of the abundances of juvenile and adult stages of all macrofaunal taxa and many meiofaunal taxa. We describe the multivariate structure of the seasonal succession of this community with a faunal distance metric approach. There were three groups of species that produced a three‐stage or triangular succession pattern. Stage 1 is defined by a March bloom of harpacticoid copepods that closely follows a benthic diatom bloom. Harpacticoid copepod abundance rapidly declines in late spring and is followed by the recruitment of four opportunistic annelids, marking the break between stages 1 and 2. Stage 2 is a dense assemblage of four surface‐deposit feeding and shallow subsurface‐deposit‐feeding annelids that reach peak abundance in June and decline in late summer, marking the break between stages 2 and 3. Stage 3 populations are more diverse than stage 2, reach peak abundance in fall, and decline in late fall. The infaunal community structure of December resembles that of the community the previous January. Succession on this mudflat is a fast‐paced and dynamic process affected by epipelic diatom production, the timing and duration of juvenile recruitment, and the ability of the infauna to survive in dense assemblages of tube builders.

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