Table S1 Raw means of each variable used in structural equation modeling. Only April data is shown for sites that were sampled in both April and May (Rocky Point and North Samish Bay), since the data between sampling dates was statistically indistinguishable. Variables are shown ± standard error, when appropriate. Transects were conducted at two elevations at each site, an upper limit of eelgrass (U) and an equivalent inundation elevation (E) (see Methods).

Code / Site Name / Latitude (°N) / Longitude (°W) / Transect / Elevation (m) / Tidal Amplitude (m) / Sediment Organic Matter (%) / C:N Ratio / Shoot Length (cm) / Proportion of Shoots that are Branches / Vegetative Shoot Density (per m2) / Flowering Shoot Density (per m2) / Seedling Density (per m2)
BLAU / South Samish Bay / 48.58 / 122.51 / E / -0.610 / 3.79 / 1.73±0.07 / 9.70±0.35 / 32.6±5.4 / 0.042±0.04 / 171±13 / 6±1 / 0±0
CARK / Carkeek Park / 47.71 / 122.38 / E / -0.668 / 4.86 / 0.74±0.07 / 9.89±0.41 / 33.8±4.9 / 0±0 / 206±43 / 6±2 / 0±0
DABO / Dabob Bay / 47.83 / 122.80 / E / -0.682 / 4.96 / 0.75±0.05 / 12.82±0.52 / 18.4±1.6 / 0±0 / 152±30 / 4±2 / 0±0
DUMA / Dumas Bay / 47.33 / 122.39 / E / -0.634 / 5.07 / 1.15±0.07 / 10.87±0.33 / 23.9±4.6 / 0±0 / 141±35 / 1±0 / 0±0
EDMO / Edmonds / 47.80 / 122.40 / E / - / 4.78 / 0.84±0.06 / 9.72±0.19 / 22.3±2.2 / 0.222±0.15 / 89±32 / 0±0 / 0±0
GOGA / Golden Gardens Park / 47.70 / 122.40 / E / -0.550 / 4.86 / 0.76±0.04 / 10.68±0.35 / 28.0±3.7 / 0±0 / 153±34 / 3±2 / 0±0
HC22 / North Hood Canal / 47.89 / 122.58 / E / -0.650 / 4.50 / 0.64±0.03 / 10.50±0.42 / 31.6±4.5 / 0.057±0.03 / 130±33 / 8±2 / 0±0
KAYA / Kayak Point / 48.13 / 122.37 / E / -0.624 / 4.89 / 1.37±0.10 / 9.99±0.50 / 37.8±4.1 / 0.375±0.13 / 49±16 / 1±1 / 0±0
LUMM / Lummi Bay / 48.78 / 122.69 / E / -0.685 / 4.07 / 1.63±0.08 / 10.31±0.15 / 21.6±2.8 / 0.444±0.29 / 108±13 / 51±6 / 1±0
LYNC / Lynch Cove / 47.43 / 122.87 / E / -0.789 / 5.30 / 2.20±0.14 / 10.26±0.40 / 40.1±8.9 / 0 / 63±7 / 0±0 / 13±2
PADL / Padilla Bay / 48.49 / 122.49 / E / -0.828 / 3.89 / 3.23±0.80 / 11.29±0.26 / 58.1±6.6 / 0.080±0.08 / 193±20 / 13±2 / 2±1
PURD / Purdy Spit, Carr Inlet / 47.38 / 122.63 / E / -0.695 / 5.74 / 1.45±0.17 / 10.49±0.13 / 14.8±1.3 / 0.031±0.03 / 260±75 / 0±0 / 0±0
ROC1 / Rocky Point, Case Inlet / 47.37 / 122.82 / E / -0.726 / 6.01 / 1.27±0.08 / 11.21±1.13 / 11.3±0.9 / 0.456±0.27 / 150±61 / 0±0 / 0±0
SEAB / Seabeck, Hood Canal / 47.66 / 122.79 / E / -0.801 / 5.05 / 1.47±0.11 / 11.69±0.64 / 13.4±2.0 / 0.333±0.33 / 277±38 / 0±0 / 0±0
SIMK / Similk Bay / 48.43 / 122.58 / E / -0.799 / 4.47 / 1.87±0.06 / 10.89±0.14 / 65.9±11.4 / 0.100±0.1 / 74±8 / 4±1 / 0±0
TAY1 / North Samish Bay / 48.61 / 122.45 / E / -0.756 / 3.79 / 2.23±0.14 / 9.36±0.19 / 25.8±4.7 / 0±0 / 121±13 / 3±1 / 33±3
UNIO / Union, Hood Canal / 47.36 / 123.10 / E / -0.675 / 5.16 / 3.18±0.14 / 11.56±0.70 / 59.3±15.2 / 0.267±0.19 / 67±7 / 2±0 / 13±2
BLAU / South Samish Bay / - / - / U / -0.254 / 3.79 / 1.07±0.05 / - / 25.8±3.5 / 0 / 103±34 / 11±2 / 0±0
CARK / Carkeek Park / - / - / U / - / 4.86 / 0.77±0.04 / - / 25.4±2.4 / 0.158±0.13 / 169±42 / 24±4 / 0±0
DABO / Dabob Bay / - / - / U / -0.541 / 4.96 / 0.77±0.02 / - / 31.6±4.6 / 0 / - / - / -
DUMA / Dumas Bay / - / - / U / -0.634 / 5.07 / 0.88±0.04 / - / - / - / - / - / -
EDMO / Edmonds / - / - / U / - / 4.78 / 0.77±0.04 / - / 20.7±1.8 / 0±0 / 41±24 / 9±3 / 0±0
GOGA / Golden Gardens Park / - / - / U / 0.119 / 4.86 / 0.93±0.04 / - / 23.0±2.8 / 0.167±0.17 / 129±34 / 10±4 / 0±0
HC22 / North Hood Canal / - / - / U / -0.650 / 4.50 / - / - / - / - / - / - / -
KAYA / Kayak Point / - / - / U / -0.624 / 4.89 / - / - / 50.8±8.1 / 0 / - / - / -
LUMM / Lummi Bay / - / - / U / -0.262 / 4.07 / 1.65±0.11 / - / 20.5±2.3 / 0.278±0.15 / 152±14 / 49±9 / 1±0
LYNC / Lynch Cove / - / - / U / -0.400 / 5.30 / 2.11±0.17 / - / 30.1±12.1 / 0±0 / 65±10 / 0±0 / 7±3
PADL / Padilla Bay / - / - / U / -0.305 / 3.89 / 2.18±0.07 / - / 28.2±4.1 / 0.083±0.08 / 110±33 / 3±1 / 0±0
PURD / Purdy Spit, Carr Inlet / - / - / U / -0.374 / 5.74 / 1.31±0.01 / - / 18.5±1.4 / 0±0 / 293±63 / 0±0 / 0±0
ROC1 / Rocky Point, Case Inlet / - / - / U / -0.464 / 6.01 / 1.07±0.06 / - / 9.5±0.8 / 0.291±0.09 / 842±134 / 0±0 / 0±0
SEAB / Seabeck, Hood Canal / - / - / U / -0.348 / 5.05 / 1.98±0.04 / - / 15.4±1.4 / 0.092±0.07 / 388±54 / 1±0 / 0±0
SIMK / Similk Bay / - / - / U / -0.217 / 4.47 / 0.92±0.08 / - / 40.7±12.4 / 0±0 / 24±8 / 1±0 / 0±0
TAY1 / North Samish Bay / - / - / U / -0.517 / 3.79 / 1.95 / - / 34.0±6.5 / 0 / 74±11 / 1±0 / 0±0
UNIO / Union, Hood Canal / - / - / U / -0.675 / 5.16 / - / - / - / - / - / - / -

1