DISTLM of the densities of <i>Cirolana harfordi</i> in oyster-beds, using Thickness of the habitat, Concentration of organic matter smaller than 64 µm (OM<64), Concentration of organic matter between 64 and 500 µm (OM 64–500) and Location as predictor variables. For marginal tests, variables are taken individually; for sequential tests, variables were chosen using Forward selection criteria. The column %var indicates the percentage of the variation explained by the predictor variables. Cum % is the cumulative percentage of variance explained.

<p>DISTLM of the densities of <i>Cirolana harfordi</i> in oyster-beds, using Thickness of the habitat, Concentration of organic matter smaller than 64 µm (OM<64), Concentration of organic matter between 64 and 500 µm (OM 64–500) and Location as predictor variables. For marginal tests, variables are taken individually; for sequential tests, variables were chosen using Forward selection criteria. The column %var indicates the percentage of the variation explained by the predictor variables. Cum % is the cumulative percentage of variance explained.</p

Relationships between <i>C. harfordi</i> and organic matter and thickness of the habitat.

<p>Densities of <i>Cirolana harfordi</i> and (A) concentration of organic matter smaller than 64 µm (triangles) and 64–500 µm (circles) and (B) thickness of the oyster-bed at Greenwich (white) and Berrys Bay (black)</p

Densities of <i>Cirolana harfordi</i> (mean ± S.E. number of individuals in 100 ml of oyster-bed) compared with densities of the most abundant arthropods (Chironomidae larvae and <i>Dynoides barnardii</i>) at Greenwich, Berrys Bay and Neutral Bay in June and October 2010. Greenwich was not sampled in June 2010 (see methods).

<p>Densities of <i>Cirolana harfordi</i> (mean ± S.E. number of individuals in 100 ml of oyster-bed) compared with densities of the most abundant arthropods (Chironomidae larvae and <i>Dynoides barnardii</i>) at Greenwich, Berrys Bay and Neutral Bay in June and October 2010. Greenwich was not sampled in June 2010 (see methods).</p

Locations sampled.

<p>Locations sampled in Sydney Harbour for oyster-beds (black circles), mussel-beds (squares) and coralline turfs (white circles).</p

Analyses of the effects of the densities of <i>Cirolana harfordi</i> on densities per taxa, total abundance and number of taxa of the assemblage in oyster-beds in June and October 2010. PERMANOVA (9999 permutations of residuals under reduced model) of Bray-Curtis similarities for the densities per taxa (forth root transformed) and Euclidean distances for total abundance and number of taxa in oyster-beds, where Location is the comparison among three locations in June and six locations in October 2010 (random) and Patch is the comparison among three patches per location (random, nested in Location), using the densities of <i>C. harfordi</i> as a covariate. Factor Patch was not included in the analysis in October 2010 (see methods). ^a Terms eliminated to increase the power for factors higher in the table.

<p>Analyses of the effects of the densities of <i>Cirolana harfordi</i> on densities per taxa, total abundance and number of taxa of the assemblage in oyster-beds in June and October 2010. PERMANOVA (9999 permutations of residuals under reduced model) of Bray-Curtis similarities for the densities per taxa (forth root transformed) and Euclidean distances for total abundance and number of taxa in oyster-beds, where Location is the comparison among three locations in June and six locations in October 2010 (random) and Patch is the comparison among three patches per location (random, nested in Location), using the densities of <i>C. harfordi</i> as a covariate. Factor Patch was not included in the analysis in October 2010 (see methods). ^a Terms eliminated to increase the power for factors higher in the table.</p

Distribution along Sydney Harbour.

<p>Mean densities of <i>Cirolana harfordi</i> (ind/100 ml of sample) in oyster-beds in Sydney Harbour. Berrys Bay, Neutral Bay and Bradley's Head were sampled in June (grey) and October (black) 2010. Henley, Greenwich and Little Manly were sampled only in October 2010 (see methods). There were no <i>C. harfordi</i> individuals found at Henley and Little Manly.</p