Datasets:
patrickbdevaney
/
mia9

Dataset card Data Studio Files
xet
 Community
1
text
stringlengths
0
6.44k
21.4% of variability in Thalassia cover-density (R
2 = 0.214) were explained by the
models. When all variables were combined, the models fit the data better than the
baseline regressions and show that for every increase in year (see Figure 8), there was a
61
decrease in Syringodium (β = -0.083, p = 0.036; Table 13, Model 2C) and Thalassia
cover-density (β = -0.062, p = 0.025; Table 13, Model 3C). Water depth (β = -0.003, p <
0.001) remained the only significant predictor of Halodule cover-density, with the model
only explaining 5.8% (R
2 = 0.058, F = 2.777, p = 0.004) of variability.
The comprehensive regression model investigating the combined effects of
temporal, environmental and physical, and algae cover-density variables on seagrass
cover-density, was the best model for each individual seagrass species (Table 13, Models
2-4D). The model significantly explained (F = 9.432, p < 0.001) 23.3% (R
2 = 0. 233) of
variability in Syringodium density. Season, temperature, salinity, turbidity, and green and
brown algae density were not significant predictors of Syringodium density (p > 0.05).
The model predicted that Syringodium cover-density would increase with shallower water
depth, lower calcareous algae cover-density, and higher red algae cover-density (p <
0.01; Table 13, Model 2D). The model also showed that Syringodium cover-density
decreased through the study period. In the model for Thalassia (F = 9.014, p < 0.001),
22.5 % (R
2 = 0. 225) of variability in cover-density was explained, with water depth as
the only significant predictor. Thalassia cover-density tended to be higher in shallower
water depth (β = -0.006, p < 0.001) (Table 13, Model 3D). Water depth and red algae
cover-density were the only significant predictors in the Halodule cover-density model (F
= 3.096, p < 0.001), which was only able to explain 9.1% (R
2 = 0. 091) variability (Table
13, Model 4D). Shallower water depth (β = -0.003, p < 0.001) and decreased red algae
cover-density (β = -0.229, p = 0.002) predicted increased Halodule cover-density.
62
Table 13. Models 2-4 A -D. Multiple Enter-wise Regression models for individual
seagrass cover-densities and environmental and physical measurements. Syringodium,
Thalassia, and Halodule seagrass cover-density measurements are in #/m2
. Water depth
and sediment depth are measured in cm, temperature is measured in oC, salinity is
measured in ‰, turbidity measured in NTU.  is an unstandardized coefficient of
regression, reported with standard error and significance, p-value. Conventional
variables include year of sample (2005-2011), season (1 = spring, 2 = fall). A. Models
evaluating seagrass cover-density for conventional variables (year*season). B. Models
evaluating seagrass cover-density for environmental variables (depth, temp, salinity, etc.).
C. Models evaluating seagrass cover-density adjusted for conventional and environmental
variables. D. Models evaluating seagrass cover-density adjusted for conventional,
environmental and habitat (algae) variables. *Significance = p < 0.05.
Model Set 2A-D Model 2-A Model 2-B
2005-2011 N  SE p N  SE p
Syringodium
Cover-Density
Year 420 -0.052 0.035 0.140
Season 0.009 0.142 0.949
Water Depth 418 -0.005 0.001 <0.001 *
Sediment Depth 0.002 0.001 0.006 *
Turbidity -0.010 0.039 0.798
Surface
Temperature -0.050 0.121 0.679
Bottom
Temperature 0.043 0.121 0.720
Surface Salinity -0.006 0.034 0.854
Bottom Salinity -0.053 0.046 0.253
Model 2-C Model 2-D
Year 418 -0.083 0.040 0.036 * Year 418 -0.113 0.038 0.003 *
Season -0.306 0.271 0.260 Season -0.154 0.260 0.554
Water Depth -0.005 0.001 <0.001 * Water Depth -0.005 0.001 <0.001 *
Sediment Depth 0.002 0.001 0.015 * Sediment Depth 0.001 0.001 0.112
Turbidity -0.054 0.045 0.233 Turbidity -0.026 0.043 0.543
Surface
Temperature -0.079 0.123 0.521
Surface
Temperature -0.105 0.118 0.371
Bottom
Temperature 0.116 0.134 0.388
Bottom
Temperature 0.227 0.130 0.080
Surface Salinity -0.003 0.034 0.928 Surface Salinity 0.002 0.032 0.955
Bottom Salinity -0.070 0.048 0.149 Bottom Salinity -0.072 0.046 0.120
Red Algae 0.629 0.101 <0.001 *
Green Algae -0.257 0.180 0.153
Brown Algae 0.355 0.377 0.348
Calcareous Algae -0.433 0.146 0.003 *
63
Model Set 3A-D Model 3-A Model 3-B
2005-2011 N  SE p N  SE p
Thalassia
Cover-Density
Year 420 -0.021 0.026 0.420
Season -0.088 0.102 0.390
Water Depth 418 -0.005 0.001 <0.001 *
Sediment Depth 0.000 0.001 0.609 *
Turbidity -0.008 0.027 0.773
Surface
Temperature 0.119 0.084 0.157
Bottom
Temperature -0.093 0.084 0.269
Surface Salinity 0.033 0.023 0.165
Bottom Salinity 0.001 0.032 0.986
Model 3-C Model 3-D
Year 418 -0.062 0.027 0.025 * Year 418 -0.054 0.028 0.052
Season 0.184 0.188 0.329 Season 0.155 0.189 0.413
Water Depth -0.005 0.001 <0.001 * Water Depth -0.006 0.001 <0.001 *
Sediment Depth 0.000 0.001 0.938 Sediment Depth 0.000 0.001 0.601