<i>Crassostrea virginica</i> abundance on caged (C), uncaged (UC) and procedural control (PC) tiles at sites characterised by high and low flow velocities.

<p>Cochran’s test, <i>C</i>  =  0.08, <i>ns</i>.</p><p>SNK test  =  << indicates p < 0.01.</p><p>Replicate tiles (<i>n</i>  =  12) were established at two sites nested within 3 locations (Murrells Inlet, North Inlet, Cape Romain) and 2 flow regimes (high, low).</p

Predator identity effects on mortality of <i>Crassostrea virginica</i>.

<p><i>C. sapidus</i> (blue) and <i>P. herbstii</i> (mud) were caged either independently or in combination with 10 oysters per cage. Crabs were included in cages at densities typical of those seen in the region (AM Knights, <i>pers. obs</i>. and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035096#pone.0035096-Grabowski1" target="_blank">[32]</a>). Data are pooled from two sites at North Inlet (<i>n</i>  =  6, a total of 30 plots). Post hoc test outcomes are shown by letters (a, b) and indicate groups of means that are indistinguishable from each other (where letters differ p < 0.01).</p

Mean recruitment (± SE) of <i>Crassostrea virginica</i> onto predator exclusion (cage), procedural control and open access (control) tiles.

<p>Recruitment tiles were established at two sites in each of three locations in South Carolina characterised by high and low flow regimes (<i>n</i> = 12; a total of 432 plots). Post hoc test outcomes are shown by letters (a, b) and indicate groups of means that are indistinguishable from each other (where letters differ p < 0.01).</p

Experimental treatments testing the predation effects of two intertidal crab species on <i>Crassostrea virginica</i>.

†<p>Indicates no cage.</p><p>Treatment codes shown: +/− indicates species inclusion/exclusion; Blue crab <i>C. sapidus;</i> Mud crab <i>P. herbstii</i>; Control − uncaged treatment. Crab species were included at densities typical of the region (<i>C. sapidus -</i> 1 per cage; <i>P. herbstii</i> – 4 per cage) (A.M. Knights, <i>pers. obs.</i> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035096#pone.0035096-Grabowski1" target="_blank">[32]</a>).</p

Flow velocity characterization of locations and sites using gypsum dissolution.

<p>Shown are mean proportional dissolution rates (± SD) of gypsum at each of three locations and four sites per location in South Carolina (<i>n</i>  =  6). Post hoc test outcomes are shown by letters (a, b) and indicate groups of means that are indistinguishable from each other (where letters differ p < 0.01).</p

Study locations (bold) on the eastern coast of the USA.

<p>Study locations (bold) on the eastern coast of the USA.</p

Flow velocity characterization of sites and locations by gypsum dissolution.

<p>Cochran’s <i>C</i>  =  0.207, <i>ns.</i></p><p>SNK test  =  << indicates p < 0.01.</p><p>Replicate gypsum dissolution clods (<i>n</i>  =  6) were haphazardly placed at each of four randomly chosen sites and three locations in South Carolina (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035096#pone-0035096-g001" target="_blank">Figure 1</a> for locations). SNK outcomes are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035096#pone-0035096-g002" target="_blank">Figure 2</a>.</p

Proportional mortality of <i>Crassostrea virginica</i> in the presence or absence of <i>C. sapidus</i> (blue crab) and/or <i>P. herbstii</i> (mud crab) at two sites in South Carolina.

<p>Cochran’s test, <i>C</i>  =  0.27, <i>ns</i>.</p>**<p>signifies p < 0.01; * signifies p < 0.05.</p><p>SNK test  =  << indicates p < 0.01; ‘−’ signifies species absent, ‘+’ signifies species present.</p><p>A separate 1-factor ANOVA was used to compare mortality between control (uncaged oysters) and the treatment containing both blue and mud crabs. No significant differences were found (<i>F</i>_{1, 11}  =  0.16, <i>ns</i>).</p

Recruit abundances of <i>Austrominius modestus</i> over time.

<p>(a) Mean recruit abundance (± SE) in 25 cm² control and cumulative plots every 2 wk (<i>n</i> = 10), (b) mean recruit abundance (± SE) in plots of difference area (cm²) (<i>n</i> = 10), and (c) mean recruit density per cm² in cumulative plots in plots of different sizes (<i>n</i> = 40). Letters over bars (a–d) indicate post-hoc comparison outcomes with the same letter indicating no significant difference between recruit abundance/density. All plots irrespective of initial clearance size are pooled in (b). The period when all cumulative plots were 100% colonised is shown (dotted line).</p

Comparative recruit density in cumulative and control plots.

<p>Change in recruit abundance in 25 cm² control and cumulative plots. Recruitment was estimated every 2 wk using non-destructive photographic sampling and image analysis. Control plots were disturbed (cleared) every 2 wk and estimates are compared to its paired cumulative plot on the same statue. Cumulative plots were undisturbed following the initial clearance. Significant regression is shown (solid line; <i>R</i>² = 0.89) and dashed lines indicate 95% confidence intervals. 45^o line indicates the point where recruitment is the same in control and cumulative plots.</p