Assemblages of invertebrates in turfing algae are diverse, complex and very variable in space and time. The assemblages colonizing pot-scourers (as artificial habitats, AHs) are, however, likely to be similar because the habitat is similar in composition, structure and complexity. Many of the variations of history and disturbances to habitat are eliminated by using AHs, so some of the processes and patterns leading to the structure of assemblages should be clearer than in natural pieces of habitat. AHs were used on subtidal rocky reefs to test hypotheses about the development of assemblages and the temporal variability found for these organisms. Models considered were that: (i) early developing assemblages are variable because of chance differences in recruitment, but later assemblages converge; (ii) early developing assemblages are similar because only some taxa can colonize new habitat, but later-assemblages diverge; (iii) early development is due to chance recruitment, but this regulates later development (so variability is maintained). Also, the model was examined that later-developing assemblages are the “sum of the parts” of earlier arrivals versus the model that assemblages develop structure through successional processes of facilitation or inhibition. Relevant experimental designs and analytical procedures are illustrated for time-courses of 1, 3 and 6 months and 1, 2 and 4 months, each in 2 sites.
