CWM_traits for aquatic plants

Data was collected in a field survey in August 2014 comprising 30 sites in the Gulf of Finland, Northern Baltic Sea. Sampled sites occurred along a wave exposure gradient and were divided into outer, middle and inner archipelago areas (see article for details). At each site, five replicate plots (1m2 each) were sampled. Trait measurements were weighted by the shoot densities of each species to retrieve the community-weighted mean trait value and standardized to have a mean of 0 and variance of 1. See article for more information on the trait measurements. The data was used in constructing Structural Equation Models. Abbreviated headlines are as follow: “CWM_SLA” = community-weighted mean specific leaf area, “CWM_Root” = community-weighted mean root length, “CWM_Hmax” = community-weighted mean maximum vegetative height, “CWM_RS = community-weighted mean root to shoot ratio, CWM_LeafN = community-weighted mean leaf nitrogen concentration, “CWM_RootN” = community-weighted root nitrogen concentration, “CWM_Leafd15N” = the community-weighted mean delta 15N of youngest leaves, “CWM_Leafd13C” = the community-weighted mean delta 13C of youngest leaves, “CWM_Rootd15N” = the community-weighted mean delta 15N of youngest roots, “lnSilt” = the ln-transformed silt-fraction and “lnPrimprod” = the ln-transformed community primary production

Effects of Richness and Shading on plant biomass change and tissue carbohydrates.

<p>Generalized Linear Models were used to analyze biomass change and plant tissue sucrose concentrations among mono- and polycultures.</p

Estimated marginal means ± SE of sediment sulfide pools (acid volatile sulfide), plant physiological variables and sediment NH₄⁺ concentrations for the sampling events (<b>A</b>) Post-shading, and (<b>B</b>) Recovery.

<p>Results from the post-hoc test were derived from Generalized Linear Models (post hoc sequential Šidák) and 2-way heterogeneous variance models (post hoc Tukey-Kramer). Differing letters after values denote significant (p<0.05) differences.</p

Figure 2

<p><b>Effects of shading on resistance and recovery of biomass production and plant tissue carbohydrate concentrations.</b> The stability properties resistance and recovery are calculated from the absolute values of (A) shoot biomass, (B) root biomass, (C) shoot sucrose and (D) root sucrose. Asterisks denote significant differences: * p≤0.05, ** p≤0.01, *** p≤0.001 between shaded mono- and polycultures.</p

Effects of Richness and Shading on plant physiological responses.

<p>Rhizome C % during Post-shading and Recovery and Shoot C:N ratio during Recovery were analyzed with a 2-way heterogeneous variance model. The degrees of freedom show ndf and ddf respectively, calculated from the Kenward-Roger method.</p

Effects of Richness and Shading on sediment biogeochemical and plant physiological responses.

<p>The analyses were based on Generalized Linear Models on sediment sulfide pools (acid volatile sulfide), plant tissue sulfide isotopic signature, porewater ammonium (NH₄⁺), plant tissue nutrients and nutrient ratios among mono- and polycultures.</p

Effects of shading on biomass production.

<p>The log ratio of the change in shoot biomass (relative values) during (A) Pre-shading, (B) Post-shading and (C) Recovery and in root biomass (relative values) during (D) Pre-shading, (E) Post-shading and (F) Recovery in shaded and non-shaded mono- and polycultures. To ascertain equal samples at each sampling event, Pre-shading treatments that had not received shading were labeled shaded (see Materials and Methods). Statistical analyses presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064064#pone-0064064-t002" target="_blank">Table 2</a>.</p

Effects of shading on plant tissue carbohydrate concentrations.

<p>Shoot sucrose concentrations during (A) Pre-shading, (B) Post-shading and (C) Recovery and root sucrose concentrations during (D) Pre-shading, (E) Post-shading and (F) Recovery of <i>Z. marina</i> grown in shaded and non-shaded mono- and polycultures. The differing letters above bars in (A) denote significant differences (p<0.05, sequential Šidák’s <i>post hoc</i> test). To ascertain equal samples at each sampling event, Pre-shading treatments that had not received shading were labeled shaded (see Materials and Methods).</p

Structural equation model on overall effects of shading and plant richness on <b><i>Zostera marina</i></b><b>.</b>

<p>The model fit was estimated through bootstrapping (N = 80, Bollen-Stripe bootstrap p = 0.48). The numbers next to arrows denote standardized path coefficients and all shown pathways are significantly different from 0 (p<0.05 level). The thickness of an arrow describes the strength of a correlation. If not mentioned otherwise, all response variables describe shoot parameters. Error terms are not presented graphically.</p

Effects of Richness and Shading on tissue carbohydrates.

<p>Shoot sucrose during Pre- and Post-shading was analyzed with a 2-way heterogeneous variance model. The degrees of freedom show ndf and ddf respectively, calculated from the Kenward-Roger method.</p