Site characteristics.

Temperature (Temp.) and Salinity: range during the experiment, “marine” = 35–37 psu. Pollution (Poll): 1 = unpolluted, 2 = moderately polluted, 3 = heavily polluted. Exposure (Expos): 1 = sheltered, 2 = moderately exposed, 3 = fully exposed. Source = nearby habitats where recruits presumably stem from: hb = hard bottom, including artificial hard substrata, sb = sandy bottom, mb = muddy bottom. 1: panel averages for numbers of taxa and functional groups. Dissimilarity (Dissim, ANOSIM R) as obtained by a dissimilarity analysis comparing the taxon composition of random pairs of panels from site A and site B within a given region on the day of transplantation. The larger R, the more dissimilar are the communities regarding composition and/or relative abundance of taxa. Since paired communities in each region were identical with regard to most aspects (age, substratum, depth) their dissimilarity is considered a proxy of the cumulated abiotic (water chemistry, pollution, exposure…) and biotic (pool of recruits, consumers,…) differences between sites and, thus, the strength of the transplantation treatment.